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Acceso Abierto
2-aminooxazole in Astrophysical Environments: IR Spectra and Destruction Cross Sections for Energetic Processing
(IOP Science Publishing, 2021-03-11) Maté, B.; Carrasco Herrera, R.; Timón, V.; Tanarro, I.; Herrero, V. J.; Carrascosa, H.; Muñoz Caro, G. M.; González Díaz, C.; Jiménez Serra, I.; Agencia Estatal de Investigación (AEI); 0000-0002-5478-8644; 0000-0002-1217-6834; 0000-0002-1888-513X; 0000-0002-7456-4832; 0000-0002-2885-4847; 0000-0001-7003-7368; 0000-0002-8789-9148; 0000-0003-4493-8714; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
2-aminooxazole (2AO), a N-heterocyclic molecule, has been proposed as an intermediate in prebiotic syntheses. It has been demonstrated that it can be synthesized from small molecules such as cyanamide and glycoaldehyde, which are present in interstellar space. The aim of this work is to provide infrared (IR) spectra, in the solid phase for conditions typical of astrophysical environments and to estimate its stability toward UV photons and cosmic rays. IR (4000–600 cm−1) absorption spectra at 20 K, 180 K, and 300 K, IR band strengths, and room-temperature UV (120–250 nm) absorption spectra are given for the first time for this species. Destruction cross sections of ≈9.5 10−18 cm2 and ≈2 10−16 cm2 were found in the irradiation at 20 K of pure 2AO and 2AO:H2O ices with UV (6.3–10.9 eV) photons or 5 keV electrons, respectively. These data were used to estimate half-life times for the molecule in different environments. It is estimated that 2AO could survive UV radiation and cosmic rays in the ice mantles of dense clouds beyond cloud collapse. In contrast, it would be very unstable on the surface of cold solar system bodies like Kuiper Belt objects, but the molecule could still survive within dust grain agglomerates or cometesimals.
Acceso Abierto
2-D organization of silica nanoparticles on gold surfaces: CO2 marker detection and storage
(Royal Society of Chemistry, 2020-08-27) Cueto Díaz, E. J.; Gálvez Martínez, S.; Torquemada, M. C.; Valles González, M. P.; Mateo Martí, Eva; Agencia Estatal de Investigación (AEI); Comunidad de Madrid; Torquemada, M. C. [0000-0002-0438-3120]; Mateo Martí, E. [0000-0003-4709-4676]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
A single layer of silica nanoparticles with an average size of ∼200 nm was deposited over the surface of pristine gold wafers, aided by (3-mercaptopropyl)trimethoxysilane. The nanoparticle immobilization was driven by covalent bonding rather than a self-assembly process, leading to a cluster-assembled material which has CO2 sensing features. Here, we show how this device can be used for CO2 physisorption and chemisorption. We analyse the device, both spectroscopically and morphologically, before and after exposure to an atmosphere of 7 mbar of CO2, inside a planetary atmospheres and surfaces simulation chamber, (PASC) mimiking Martian atmospheric conditions. Our studies demonstrate that these clusters are suitable for CO2 detection and storage, under well controlled experimental Martian conditions. Their high sensitivity at a very low concentration of CO2, 12.4 ppm, makes them ideal candidates in the nanosensor field.
Restringido
2D kinematics of massive stars near the Galactic Centre
(Oxford Academics: Oxford University Press, 2021-01-14) Libralato, M.; Lennon, D. J.; Bellini, A.; Van der Marel, R.; Clark, S. J.; Najarro, F.; Patrick, Lee R.; Anderson, J.; Bedin, L. R.; Crowther, P. A.; Mink, S. E.; Evans, C. J.; Platais, I.; Sabbi, E.; Sohn, S. T.; Agencia Estatal de Investigación (AEI); Agencia Canaria de Investigación, Innovación y Sociedad de la Información (ACIISI); Generalitat Valenciana; Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR); Bedin, L. [0000-0003-4080-6466]; Patrick, L. [0000-0002-9015-0269]; Libralato, M. [0000-0001-9673-7397]
The presence of massive stars (MSs) in the region close to the Galactic Centre (GC) poses several questions about their origin. The harsh environment of the GC favours specific formation scenarios, each of which should imprint characteristic kinematic features on the MSs. We present a 2D kinematic analysis of MSs in a GC region surrounding Sgr A* based on high-precision proper motions obtained with the Hubble Space Telescope. Thanks to a careful data reduction, well-measured bright stars in our proper-motion catalogues have errors better than 0.5 mas yr−1. We discuss the absolute motion of the MSs in the field and their motion relative to Sgr A*, the Arches, and the Quintuplet. For the majority of the MSs, we rule out any distance further than 3–4 kpc from Sgr A* using only kinematic arguments. If their membership to the GC is confirmed, most of the isolated MSs are likely not associated with either the Arches or Quintuplet clusters or Sgr A*. Only a few MSs have proper motions, suggesting that they are likely members of the Arches cluster, in agreement with previous spectroscopic results. Line-of-sight radial velocities and distances are required to shed further light on the origin of most of these massive objects. We also present an analysis of other fast-moving objects in the GC region, finding no clear excess of high-velocity escaping stars. We make our astro-photometric catalogues publicly available.
Acceso Abierto
A broadband X-ray view of the NLSy1 1E 0754.6+3928
(EDP Sciences, 2020-02-28) Middei, R.; Tombesi, F.; Vagnetti, F.; Serafinelli, R.; Bianchi, S.; Miniutti, G.; Marinucci, A.; Matzeu, G. A.; Petrucci, P. O.; Ursini, F.; Zaino, A.; Agenzia Spaziale Italiana (ASI); Istituto Nazionale Astrofisica (INAF); European Space Agency (ESA); 0000-0001-9815-9092; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. The soft X-ray band of many active galactic nuclei (AGNs) is affected by obscuration due to partially ionised matter crossing our line of sight. In this context, two past XMM-Newton observations that were six months apart and a simultaneous NuSTAR-Swift exposure of the Narrow Line Seyfert 1 galaxy 1E 0754.6+3928, which was approximately eight years later, revealed an intense and variable warm absorber (WA) and hints of additional absorbers in the Fe K alpha band.Aims. We aim to provide the first X-ray characterisation of this AGN by discussing its broadband (0.3-79 keV) spectrum and temporal properties.Methods. We conduct a temporal and spectroscopic analysis on two similar to 10 ks (net exposure) XMM-Newton snapshots performed in April and October 2006. We also study the high energy behaviour of 1E 0754.6+3928 and model its broadband spectrum by using simultaneous Swift-NuSTAR data. Both phenomenological and physically motivated models are tested.Results. We find the presence of flux variability of similar to 150% and 30% for 0.3-2 and 2-10 keV bands, respectively, and spectral changes at months timescales of Delta Gamma similar to 0.4. A reflection component that is consistent with being constant over years and arising from relatively cold material that is far from the central super massive black hole is detected. The main spectral feature shaping the 1E 0754.6+3928 spectrum is a WA. Such a component is persistent over the years and the variability of its ionisation and column density is observed down on months in the ranges 3x10(22)cm(-2)less than or similar to N-H less than or similar to 7.2x10(22)cm(-2) and 1.5 less than or similar to log (xi/erg s(-1) cm) less than or similar to 2.1. Despite the short exposures, we find possible evidence of two additional high-ionisation and high-velocity outflow components in absorption.Conclusions. Our analysis suggests the existence of a complex system of absorbers in 1E 0754.6+3928. Longer exposures are required in order to characterise, on more solid grounds, the absorbers in this AGN.
Acceso Abierto
A Catalog of Galactic Multiple Systems with a Red Supergiant and a B Star.
(The Institute of Physics (IOP), 2020-01-27) Pantaleoni González, M.; Maíz Apellániz, J.; Barbá, R. H.; Negueruela, I.
This article has no abstract
Restringido
A Catalog of Wide Binary and Multiple Systems of Bright Stars from Gaia-DR2 and the Virtual Observatory
(The Institute of Physics (IOP), 2019-01-28) Jiménez Esteban, F. M.; Rodrigo, C.; Solano, Enrique; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI); European Research Council (ERC); Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Binary and multiple stars have long provided an effective empirical method of testing stellar formation and evolution theories. In particular, the existence of wide binary systems (separations >20,000 au) is particularly challenging to binary formation models as their physical separations are beyond the typical size of a collapsing cloud core (~5000–10,000 au). We mined the recently published Gaia-DR2 catalog to identify bright comoving systems in the five-dimensional space (sky position, parallax, and proper motion). We identified 3741 comoving binary and multiple stellar candidate systems, out of which 575 have compatible radial velocities for all the members of the system. The candidate systems have separations between ~400 and 500,000 au. We used the analysis tools of the Virtual Observatory to characterize the comoving system members and to assess their reliability. The comparison with previous comoving systems catalogs obtained from TGAS showed that these catalogs contain a large number of false systems. In addition, we were not able to confirm the ultra-wide binary population presented in these catalogs. The robustness of our methodology is demonstrated by the identification of well known comoving star clusters and by the low contamination rate for comoving binary systems with projected physical separations <50,000 au. These last constitute a reliable sample for further studies. The catalog is available online at the Spanish Virtual Observatory portal (http://svo2.cab.inta-csic.es/vocats/v2/comovingGaiaDR2/).
Acceso Abierto
A Catalog of Wide Binary and Multiple Systems of Bright Stars from Gaia-DR2 and the Virtual Observatory
(American Astronomical Society, 2019) Jiménez Esteban, F. M.; Rodrigo, C.; Solano, Enrique
Binary and multiple stars have long provided an effective empirical method of testing stellar formation and evolution theories. In particular, the existence of wide binary systems (separations >20,000 au) is particularly challenging to binary formation models as their physical separations are beyond the typical size of a collapsing cloud core (∼5000-10,000 au). We mined the recently published Gaia-DR2 catalog to identify bright comoving systems in the five-dimensional space (sky position, parallax, and proper motion). We identified 3741 comoving binary and multiple stellar candidate systems, out of which 575 have compatible radial velocities for all the members of the system. The candidate systems have separations between ∼400 and 500,000 au. We used the analysis tools of the Virtual Observatory to characterize the comoving system members and to assess their reliability. The comparison with previous comoving systems catalogs obtained from TGAS showed that these catalogs contain a large number of false systems. In addition, we were not able to confirm the ultra-wide binary population presented in these catalogs. The robustness of our methodology is demonstrated by the identification of well known comoving star clusters and by the low contamination rate for comoving binary systems with projected physical separations <50,000 au. These last constitute a reliable sample for further studies. The catalog is available online at the Spanish Virtual Observatory portal (http://svo2.cab.inta-csic.es/vocats/v2/comovingGaiaDR2/).
Acceso Abierto
A chemical study of carbon fractionation in external galaxies
(Oxford Academics: Blackwell Publishing, 2020-07-18) Viti, S.; Fontani, F.; Jiménez Serra, I.; Agencia Estatal de Investigación (AEI); European Research Council (ERC); Science and Technology Facilities Council (STFC); 0000-0003-4493-8714; 0000-0003-0348-3418; 0000-0001-8504-8844; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
In the interstellar medium carbon exists in the form of two stable isotopes 12C and 13C and their ratio is a good indicator of nucleosynthesis in galaxies. However, chemical fractionation can potentially significantly alter this ratio and in fact observations of carbon fractionation within the same galaxy has been found to vary from species to species. In this paper, we theoretically investigate the carbon fractionation for selected abundant carbon-bearing species in order to determine the conditions that may lead to a spread of the 12C/13C ratio in external galaxies. We find that carbon fractionation is sensitive to almost all the physical conditions we investigated, it strongly varies with time for all species but CO, and shows pronounced differences across species. Finally, we discuss our theoretical results in the context of the few observations of the 12C/13C in both local and higher redshift galaxies.
Acceso Abierto
A CO molecular gas wind 340 pc away from the Seyfert 2 nucleus in ESO 420-G13 probes an elusive radio jet
(EDP Sciences, 2020-01-21) Fernández Ontiveros, J. A.; Dasyra, K. M.; Hatziminaoglou, Evanthia; Malkan, M. A.; Pereira Santaella, M.; Papachristou, M.; Spinoglio, L.; Combes, F.; Aalto, S.; Nagar, N.; Imanishi, M.; Andreani, P.; Ricci, C.; Slater, R.; Agenzia Spaziale Italiana (ASI); Comunidad de Madrid; Hellenic Foundation for Research and Innovation (HFRI); Comisión Nacional de Investigación Científica y Tecnológica (CONICYT); http://dx.doi.org/10.13039/501100002848; Fernández Ontiveros, J. A. [0000-0001-9490-899X]; Hatziminaoglou, E. [0000-0003-0917-9636]; Spignoglio, L. [0000-0001-8840-1551]; Combes, F. [0000-0003-2658-7893]; Nagar, N. [0000-0001-6920-662X]; Imanishi, M. [0000-0001-6186-8792]; Andreani, P. [0000-0001-9493-0169]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
A prominent jet-driven outflow of CO(2-1) molecular gas is found along the kinematic minor axis of the Seyfert 2 galaxy ESO 420-G13, at a distance of 340-600 pc from the nucleus. The wind morphology resembles the characteristic funnel shape, formed by a highly collimated filamentary emission at the base, and likely traces the jet propagation through a tenuous medium, until a bifurcation point at 440 pc. Here the jet hits a dense molecular core and shatters, dispersing the molecular gas into several clumps and filaments within the expansion cone. We also trace the jet in ionised gas within the inner less than or similar to 340 pc using the [NeII](12.8 mu m) line emission, where the molecular gas follows a circular rotation pattern. The wind outflow carries a mass of similar to 8 x 10(6) M-circle dot at an average wind projected speed of similar to 160 km s(-1), which implies a mass outflow rate of similar to 14 M-circle dot yr(-1). Based on the structure of the outflow and the budget of energy and momentum, we discard radiation pressure from the active nucleus, star formation, and supernovae as possible launching mechanisms. ESO 420-G13 is the second case after NGC 1377 where a previously unknown jet is revealed through its interaction with the interstellar medium, suggesting that unknown jets in feeble radio nuclei might be more common than expected. Two possible jet-cloud configurations are discussed to explain an outflow at this distance from the AGN. The outflowing gas will likely not escape, thus a delay in the star formation rather than quenching is expected from this interaction, while the feedback effect would be confined within the central few hundred parsecs of the galaxy.
Acceso Abierto
A Comodulation Analysis of Atmospheric Energy Injection Into the Ground Motion at InSight, Mars
(Advancing Earth and Space Science AGU, 2021-02-08) Charalambous, C.; Stott, A. E.; Pike, W. T.; McClean, J. B.; Warren, T.; Spiga, A.; Banfield, D.; García, R. F.; Clinton, J.; Stähler, S. C.; Navarro, Sara; Lognonné, P.; Scholz, J. R.; Kawamura, T.; Van Driel, M.; Böse, M.; Ceylan, S.; Khan, A.; Horleston, A.; Orhand Mainsant, G.; Sotomayor, L. M.; Murdoch, N.; Giardini, D.; Banerdt, W. B.; Murdoch, N. [0000-0002-9701-4075]; Lognonne, P. [0000-0002-1014-920X]; Charalambous, C. [0000-0002-9139-3895]; Stott, A. E. [0000-0001-6121-705X]; Spiga, A. [0000-0002-6776-6268]; Stähler, S. [0000-0002-0783-2489]; Scholz, J. R. [0000-0003-1404-2335]; Ceylan, S. [0000-0002-6552-6850]; Khan, A. [0000-0003-4462-3173]; Van Driel, M. [0000-0002-8938-4615]; Horleston, A. [0000-0002-6748-6522]; Giardini, D. [0000-0002-5573-7638]; Banerdt, W. B. [0000-0003-3125-1542]
Seismic observations involve signals that can be easily masked by noise injection. For the NASA Mars lander InSight, the atmosphere is a significant noise contributor, impeding the identification of seismic events for two-thirds of a Martian day. While the noise is below that seen at even the quietest sites on Earth, the amplitude of seismic signals on Mars is also considerably lower, requiring an understanding and quantification of environmental injection at unprecedented levels. Mars’ ground and atmosphere are a continuously coupled seismic system, and although atmospheric functions are of distinct origins, the superposition of these noise contributions is poorly understood, making separation a challenging task. We present a novel method for partitioning the observed signal into seismic and environmental contributions. Atmospheric pressure and wind fluctuations are shown to exhibit temporal cross-frequency coupling across multiple bands, injecting noise that is neither random nor coherent. We investigate this through comodulation, quantifying the synchrony of the seismic motion, wind and pressure signals. By working in the time-frequency domain, we discriminate between the different origins of underlying processes and determine the site's environmental sensitivity. Our method aims to create a virtual vault at InSight's landing site on Mars, shielding the seismometers with effective postprocessing in lieu of a physical vault. This allows us to describe the environmental and seismic signals over a sequence of sols, to quantify the wind and pressure injection and estimate the seismic content of possible marsquakes with a signal-to-noise ratio that can be quantified in terms of environmental independence. Finally, we exploit the relationship between the comodulated signals to identify their sources.
Restringido
A Comparative Study on HCN Polymers Synthesized by Polymerization of NH4CN or Diaminomaleonitrile in Aqueous Media: New Perspectives for Prebiotic Chemistry and Materials Science
(Chemistry Europe: European Chemical Societies Publishing, 2019-08-02) Ruiz Bermejo, Marta; De la Fuente, J. L.; Carretero González, J.; García Fernández, L.; Rosa Aguilar, M.; Agencia Estatal de Investigación (AEI); Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
HCN polymers are a group of complex and heterogeneous substances that are widely known in the fields of astrobiology and prebiotic chemistry. In addition, they have recently received considerable attention as potential functional material coatings. However, the real nature and pathways of formation of HCN polymers remain open questions. It is well established that the tuning of macromolecular structures determines the properties and practical applications of a polymeric material. Herein, different synthetic conditions were explored for the production of HCN polymers from NHCN or diaminomaleonitrile in aqueous media with different concentrations of the starting reactants and several reaction times. By using a systematic methodology, both series of polymers were shown to exhibit similar, but not identical, spectroscopic and thermal fingerprints, which resulted in a clear differentiation of their morphological and electrochemical properties. New macrostructures are proposed for HCN polymers, and promising insights are discussed for prebiotic chemistry and materials science on the basis of the experimental results.
Acceso Abierto
A Complete 16 μm Selected Galaxy Sample at z ∼ 1: Mid-infrared Spectral Energy Distributions
(IOP Science Publishing, 2021-05-28) Huang, J. S.; Dai, Y. S.; Willner, S. P.; Faber, S. M.; Cheng, C.; Xu, H.; Yan, H.; Wu, S.; Shao, X.; Hao, C.; Xia, X.; Rigopoulou, D.; Pereira Santaella, M.; Magdis, Georgios E.; Cortzen, I.; Fazio, G. G.; Assmann, P.; Fan, L.; Musin, M.; Zang, Z.; Xu, K. C.; He, C.; Jin, G.; Esamdin, A.; National Natural Science Foundation of China (NSFC); Chinese Academy of Sciences (CAS); Danish National Research Foundation (DNRF); Science and Technology Facilities Council (STFC); South America Center for Astronomy (CASSACA); Huang, J. S. [0000-0001-6511-8745]; Dai, Y. S. [0000-0002-7928-416X]; Willner, S. P. [0000-0002-9895-5758]; Faber, S. M. [0000-0003-4996-214X]; Cheng, C. [0000-0003-0202-0534]; Yan, H. [0000-0001-7592-7714]; Rigopoulou, D. [0000-0001-6854-7545]; Pereira Santaella, M. [0000-0002-4005-9619]; Magdis, G. [0000-0002-4872-2294]; Cortzen, I. [0000-0001-9197-7623]; Fazio, G. G. [0000-0002-0670-0708]; Fan, L. [0000-0003-4200-4432]; Jin, G. [0000-0003-3087-318X]; Esamdin, A. [0000-0003-1845-4900]
We describe a complete, flux-density-limited sample of galaxies at redshift 0.8 < z < 1.3 selected at 16 μm. At the selection wavelength near 8 μm rest, the observed emission comes from both dust heated by intense star formation and active galactic nuclei (AGNs). Fitting the spectral energy distributions (SEDs) of the sample galaxies to local-galaxy templates reveals that more than half the galaxies have SEDs dominated by star formation. About one-sixth of the galaxy SEDs are dominated by an AGN, and nearly all of the rest of the SEDs are composite. Comparison with X-ray and far-infrared observations shows that combinations of luminosities at rest-frame 4.5 and 8 μm give good measures of both AGN luminosity and star formation rate. The sample galaxies mostly follow the established star-forming main sequence for z = 1 galaxies, but of the galaxies more than 0.5 dex above that main sequence, more than half have AGN-type SEDs. Similarly, the most luminous AGNs tend to have higher star formation rates than the main-sequence value. Galaxies with stellar masses >1011 M⊙ are unlikely to host an AGN. About 1% of the sample galaxies show an SED with dust emission typical of neither star formation nor an AGN.
Acceso Abierto
A Comprehensive Review of HCN-Derived Polymers
(Multidisciplinary Digital Publishing Institute (MDPI), 2021-03-29) Ruiz Bermejo, Marta; De la Fuente, J. L.; Pérez Fernández, Cristina; Mateo Martí, Eva; Ruiz Bermejo, M. [0000-0002-8059-1335]; Mateo Martí, E. [0000-0003-4709-4676]; Unidad de Excelencia Científica María de Maeztu del Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
HCN-derived polymers are a heterogeneous group of complex substances synthesized from pure HCN; from its salts; from its oligomers, specifically its trimer and tetramer, amino-nalono-nitrile (AMN) and diamino-maleo-nitrile (DAMN), respectively; or from its hydrolysis products, such as formamide, under a wide range of experimental conditions. The characteristics and properties of HCN-derived polymers depend directly on the synthetic conditions used for their production and, by extension, their potential applications. These puzzling systems have been known mainly in the fields of prebiotic chemistry and in studies on the origins of life and astrobiology since the first prebiotic production of adenine by Oró in the early years of the 1960s. However, the first reference regarding their possible role in prebiotic chemistry was mentioned in the 19th century by Pflüger. Currently, HCN-derived polymers are considered keys in the formation of the first and primeval protometabolic and informational systems, and they may be among the most readily formed organic macromolecules in the solar system. In addition, HCN-derived polymers have attracted a growing interest in materials science due to their potential biomedical applications as coatings and adhesives; they have also been proposed as valuable models for multifunctional materials with emergent properties such as semi-conductivity, ferroelectricity, catalysis and photocatalysis, and heterogeneous organo-synthesis. However, the real structures and the formation pathways of these fascinating substances have not yet been fully elucidated; several models based on either computational approaches or spectroscopic and analytical techniques have endeavored to shed light on their complete nature. In this review, a comprehensive perspective of HCN-derived polymers is presented, taking into account all the aspects indicated above.
Acceso Abierto
A comprehensive study of NGC 2345, a young open cluster with a low metallicity
(EDP Sciences, 2019-11-05) Alonso Santiago, J.; Negueruela, I.; Marco, A.; Tabernero, H.; González Fernández, C.; Castro, N.; European Southern Observatory (ESO); Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); European Research Council (ERC); González Fernández, C. [0000-0003-2612-0118]; Tabernero, H. [0000-0002-8087-4298]; Castro, N. [0000-0003-0521-473X]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. NGC 2345 is a young open cluster that hosts seven blue and red supergiants, low metallicity, and a high fraction of Be stars, which makes it a privileged laboratory to study stellar evolution. Aims. We aim to improve the determination of the cluster parameters and study the Be phenomenon. Our objective is also to characterise the seven evolved stars found in NGC 2345 by deriving their atmospheric parameters and chemical abundances. Methods. We performed a complete analysis combining for the first time ubvy photometry with spectroscopy as well as the Gaia Data Release 2. We obtained spectra with classification purposes for 76 stars and high-resolution spectroscopy for an in-depth analysis of the blue and red evolved stars. Results. We identify a new red supergiant and 145 B-type likely members within a radius of 18.7 ± 1.2 arcmin, which implies an initial mass, Mcl ≈ 5200 M⊙. We find a distance of 2.5 ± 0.2 kpc for NGC 2345, placing it at RGC = 10.2 ± 0.2 kpc. Isochrone fitting supports an age of 56 ± 13 Ma, implying masses around 6.5 M⊙ for the supergiants. A high fraction of Be stars (≈10%) is found. From the spectral analysis we estimate an average vrad = +58.6 ± 0.5 km s−1 and a low metallicity, [Fe/H] = −0.28 ± 0.07, for the cluster. We also determine chemical abundances for Li, O, Na, Mg, Si, Ca, Ti, Ni, Rb, Y, and Ba for the evolved stars. The chemical composition of the cluster is consistent with that of the Galactic thin disc. One of the K supergiants, S50, is a Li-rich star, presenting an A(Li) ≈ 2.1. An overabundance of Ba is found, supporting the enhanced s-process. Conclusions. NGC 2345 has a low metallicity for its Galactocentric distance, which is comparable to typical Large Magellanic Cloud stars. It is massive enough to serve as a test bed for theoretical evolutionary models for massive intermediate-mass stars.
Acceso Abierto
A detailed non-LTE analysis of LB-1: Revised parameters and surface abundances
(EDP Sciences, 2020-01-31) Simón Díaz, S.; Maíz Apellániz, J.; Lennon, D. J.; Allende Prieto, C.; Castro, N.; De Burgos, A.; Dufton, P. L.; Herrero, A.; Toledo Padrón, B.; Smartt, S. J.; González Hernández, Carmen; Agencia Estatal de Investigación (AEI); Ministerio de Economía y Competitividad (MINECO); Science and Technology Facilities Council (STFC); Simón Díaz, S. [0000-0003-1168-3524]; Maíz Apellániz, J. [0000-0003-0825-3443]; Lennon, D. J. [0000-0003-3063-4867]; González Hernández, J. I. [0000-0002-0264-7356]; Castro, N. [0000-0003-0521-473X]; De Burgos, A. [0000-0003-4729-0722]; Herrero, A. [0000-0001-8768-2179]; Toledo Padrón, B. [0000-0002-8194-215X]; Smartt, S. J. [0000-0002-8229-1731]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. It has recently been proposed that LB-1 is a binary system at 4 kpc consisting of a B-type star of 8 M-circle dot and a massive stellar black hole (BH) of 70 M-circle dot. This finding challenges our current theories of massive star evolution and formation of BHs at solar metallicity. Aims. Our objective is to derive the effective temperature, surface gravity, and chemical composition of the B-type component in order to determine its nature and evolutionary status and, indirectly, to constrain the mass of the BH. Methods. We use the non-LTE stellar atmosphere code FASTWIND to analyze new and archival high-resolution data. Results. We determine (T-eff, log g) values of (14& x2006;000 +/- 500 K, 3.50 +/- 0.15 dex) that, combined with the Gaia parallax, imply a spectroscopic mass, from log g, of 3.2(-1.9)(+2.1) M(circle dot)3.2-1.9+2.1M circle dot$ 3.2<^>{+2.1}_{-1.9}\,M_\odot $ and an evolutionary mass, assuming single star evolution, of 5.2(-0.6)(+0.3) M(circle dot)5.2-0.6+0.3M circle dot$ 5.2<^>{+0.3}_{-0.6}\,M_\odot $. We determine an upper limit of 8 km s(-1) for the projected rotational velocity and derive the surface abundances; we find the star to have a silicon abundance below solar, and to be significantly enhanced in nitrogen and iron and depleted in carbon and magnesium. Complementary evidence derived from a photometric extinction analysis and Gaia yields similar results for T-eff and log g and a consistent distance around 2 kpc. Conclusions. We propose that the B-type star is a slightly evolved main sequence star of 3-5 M-circle dot with surface abundances reminiscent of diffusion in late B/A chemically peculiar stars with low rotational velocities. There is also evidence for CN-processed material in its atmosphere. These conclusions rely critically on the distance inferred from the Gaia parallax. The goodness of fit of the Gaia astrometry also favors a high-inclination orbit. If the orbit is edge-on and the B-type star has a mass of 3-5 M-circle dot, the mass of the dark companion would be 4-5 M-circle dot, which would be easier to explain with our current stellar evolutionary models.
Restringido
A dual perspective on the microwave-assisted synthesis of HCN polymers towards the chemical evolution and design of functional materials
(Nature Research Journals, 2020-12-18) Hortal, Lucia; Pérez Fernández, Cristina; De la Fuente, J. L.; Valles González, M. P.; Mateo Martí, Eva; Ruiz Bermejo, Marta; Instituto Nacional de Técnica Aeroespacial (INTA); Agencia Estatal de Investigación (AEI); http://dx.doi.org/10.13039/501100011033; http://dx.doi.org/10.13039/501100010687; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
In this paper, the first study on NH4CN polymerization induced by microwave radiation is described, where a singular kinetic behaviour, especially when this reaction is conducted in the absence of air, is found. As a result, a complex conjugated N-heterocyclic polymer system is obtained, whose properties are very different, and even improved according to morphological features, characterized by their X-ray diffraction patterns and scanning electron microscopy analysis, with respect to those produced under conventional thermal treatment. In addition, a wide variety of relevant bioorganics have been identified, such as amino acids, nucleobases, co-factors, etc., from the synthetized NH4CN polymers. These particular families of polymers are of high interest in the fields of astrobiology and prebiotic chemistry and, more recently, in the development of smart multifunctional materials. From an astrobiological perspective, microwave-driven syntheses may simulate hydrothermal environments, which are considered ideal niches for increasing organic molecular complexity, and eventually as scenarios for an origin of life. From an industrial point of view and for potential applications, a microwave irradiation process leads to a notable decrease in the reaction times, and tune the properties of these new series macromolecular systems. The characteristics found for these materials encourage the development of further systematic research on this alternative HCN polymerization.
Acceso Abierto
A Duality in the Origin of Bulges and Spheroidal Galaxies
(IOP Science Publishing, 2021-06-02) Constantin, L.; Pérez González, P. G.; Méndez Abreu, J.; Huertas Company, M.; Dimauro, P.; Alcalde Pampliega, B.; Buitrago, F.; Ceverino, D.; Daddi, E.; Domínguez Sánchez, H.; Espino Briones, N.; Hernán Caballero, A.; Koekemoer, A. M.; Rodighiero, G.; Constantin, L. [0000-0001-6820-0015]; Pérez González, P. G. [0000-0003-4528-5639]; Méndez Abreu, J. [0000-0002-8766-2597]; Huertas Company, M. [0000-0002-1416-8483]; Dimauro, P. [0000-0001-7399-2854]; Alcalde Pampliega, B. [0000-0002-4140-0428]; Buitrago, F. [0000-0002-2861-9812]; Caverino, D. [0000-0002-8680-248X]; Daddi, E. [0000-0002-3331-9590]; Domínguez Sánchez, H. [0000-0002-9013-1316]; Espino Briones, N. [0000-0001-6426-3844]; Hernán Caballero, A. [0000-0002-4237-5500]; Koekemoer, A. M. [0000-0002-6610-2048]; Rodighiero, G. [0000-0002-9415-2296]
Studying the resolved stellar populations of the different structural components that build massive galaxies directly unveils their assembly history. We aim at characterizing the stellar population properties of a representative sample of bulges and pure spheroids in massive galaxies (M⋆ > 1010 M⊙) in the GOODS-N field. We take advantage of the spectral and spatial information provided by SHARDS and Hubble Space Telescope data to perform the multi-image spectrophotometric decoupling of the galaxy light. We derive the spectral energy distribution separately for bulges and disks in the redshift range 0.14 < z ≤ 1 with spectral resolution R ∼ 50. Analyzing these spectral energy distributions, we find evidence of a bimodal distribution of bulge formation redshifts. We find that 33% of them present old mass-weighted ages, implying a median formation redshift ${z}_{\mathrm{form}}={6.2}_{-1.7}^{+1.5}$. They are relics of the early universe embedded in disk galaxies. A second wave, dominant in number, accounts for bulges formed at median redshift ${z}_{\mathrm{form}}={1.3}_{-0.6}^{+0.6}$. The oldest (first-wave) bulges are more compact than the youngest. Virtually all pure spheroids (i.e., those without any disk) are coetaneous with the second-wave bulges, presenting a median redshift of formation ${z}_{\mathrm{form}}={1.1}_{-0.3}^{+0.3}$. The two waves of bulge formation are distinguishable not only in terms of stellar ages but also in star formation mode. All first-wave bulges formed fast at z ∼ 6, with typical timescales around 200 Myr. A significant fraction of the second-wave bulges assembled more slowly, with star formation timescales as long as 1 Gyr. The results of this work suggest that the centers of massive disk-like galaxies actually harbor the oldest spheroids formed in the universe.
Restringido
A dynamic black hole corona in an active galaxy through X-ray reverberation mapping
(Springer Nature Research Journals, 2020-01-20) Alston, W. N.; Fabian, A. C.; Kara, E.; Parker, M. L.; Dovciak, M.; Pinto, C.; Jiang, J.; Middleton, M. J.; Miniutti, G.; Walton, D. J.; Wilkins, D. R.; Buisson, D. J.; Caballero García, M. D.; Cackett, E. M.; De Marco, B.; Gallo, L. C.; Lohfink, A. M.; Reynolds, C. S.; Uttley, P.; Young, A. J.; Zogbhi, A.; European Research Council (ERC); Science and Technology Facilities Council (STFC); European Space Agency (ESA); European Commission (EC); Agencia Estatal de Investigación (AEI); 0000-0003-2658-6559; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
X-ray reverberation echoes are assumed to be produced in the strongly distorted spacetime around accreting supermassive black holes. This signal allows us to spatially map the geometry of the inner accretion flow1,2—a region that cannot yet be spatially resolved by any telescope—and provides a direct measure of the black hole mass and spin. The reverberation timescale is set by the light travel path between the direct emission from a hot X-ray corona and the reprocessed emission from the inner edge of the accretion disk3,4,5,6. However, there is an inherent degeneracy in the reverberation signal between black hole mass, inner disk radius and height of the illuminating corona above the disk. Here we use a long X-ray observation of the highly variable active galaxy IRAS 13224−3809 to track the reverberation signal as the system evolves on timescales of a day7,8. With the inclusion of all the relativistic effects, modelling reveals that the height of the X-ray corona increases with increasing luminosity, providing a dynamic view of the inner accretion region. This simultaneous modelling allows us to break the inherent degeneracies and obtain an independent timing-based estimate for the mass and spin of the black hole. The uncertainty on black hole mass is comparable to the leading optical reverberation method9, making X-ray reverberation a powerful technique, particularly for sources with low optical variability10.
Acceso Abierto
A few StePS forward in unveiling the complexity of galaxy evolution: light-weighted stellar ages of intermediate-redshift galaxies with WEAVE
(EDP Sciences, 2019-11-21) Costantin, L.; Lovino, A.; Zibetti, S.; Longhetti, M.; Gallazzi, A.; Mercurio, A.; Lonoce, I.; Balcells, M.; Bolzonella, M.; Busarello, G.; Dalton, G.; Ferré Mateu, A.; García Benito, R.; Gargiulo, A.; Haines, C.; Jin, S.; La Barbera, F.; McGee, S.; Merluzzi, P.; Morelli, L.; Murphy, D. N. A.; Peralta de Arriba, L.; Pizzella, A.; Poggianti, B. M.; Pozzetti, L.; Sánchez Blázquez, P.; Talia, M.; Tortora, C.; Trager, S. C.; Vazdekis, A.; Vergani, D.; Vulcani, B.; Istituto Nazionale di Astrofisica (INAF); Comunidad de Madrid; Fundación Caixa; Agencia Estatal de Investigación (AEI); Vulcani, B. [0000-0003-0980-1499]; De Arribas, L. P. [0000-0002-3084-084X]; Zibetti, S. [0000-0003-1734-8356]; Talia, M. [0000-0003-4352-2063]; Tortora, C. [0000-0001-7958-6531]; Pizzella, A. [0000-0001-9585-417X]; Ferré Mateu, A. [0000-0002-6411-220X]; McGee, S. [0000-0003-3255-3139]; Gargiulo, A. [0000-0002-3351-1216]; Longhetti, M. [0000-0002-6142-4822]; Gallazzi, A. [0000-0002-9656-1800]; Vergani, D. [0000-0003-0898-2216]; Haines, C. [0000-0002-8814-8960]; Costantin, L. [0000-0001-6820-0015]; Pozzetti, L. [0000-0001-7085-0412]; Dalton, G. [0000-0002-3031-2588]; Iovino, A. [0000-0001-6958-0304]; Sánchez Blázquez, P. [0000-0003-0651-0098]; Merluzzi, P. [0000-0003-3966-2397]; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. The upcoming new generation of optical spectrographs on four-meter-class telescopes, with their huge multiplexing capabilities, excellent spectral resolution, and unprecedented wavelength coverage, will provide invaluable information for reconstructing the history of star formation in individual galaxies up to redshifts of about 0.7. Aims. We aim at defining simple but robust and meaningful physical parameters that can be used to trace the coexistence of widely diverse stellar components: younger stellar populations superimposed on the bulk of older ones. Methods. We produced spectra of galaxies closely mimicking data from the forthcoming Stellar Populations at intermediate redshifts Survey (StePS), a survey that uses the WEAVE spectrograph on the William Herschel Telescope. First, we assessed our ability to reliably measure both ultraviolet and optical spectral indices in galaxies of different spectral types for typically expected signal-to-noise ratios. We then analyzed such mock spectra with a Bayesian approach, deriving the probability density function of r- and u-band light-weighted ages as well as of their difference. Results. We find that the ultraviolet indices significantly narrow the uncertainties in estimating the r- and u-band light-weighted ages and their difference in individual galaxies. These diagnostics, robustly retrievable for large galaxy samples even when observed at moderate signal-to-noise ratios, allow us to identify secondary episodes of star formation up to an age of ∼0.1 Gyr for stellar populations older than ∼1.5 Gyr, pushing up to an age of ∼1 Gyr for stellar populations older than ∼5 Gyr. Conclusions. The difference between r-band and u-band light-weighted ages is shown to be a powerful diagnostic to characterize and constrain extended star-formation histories and the presence of young stellar populations on top of older ones. This parameter can be used to explore the interplay between different galaxy star-formation histories and physical parameters such as galaxy mass, size, morphology, and environment.
Acceso Abierto
A giant exoplanet orbiting a very-low-mass star challenges planet formation models
(American Association for the Advancement of Science, 2019-09-27) Morales, J. C.; Mustill, A. J.; Ribas, I.; Davies, M. B.; Reiners, A.; Bauer, F. F.; Kossakowski, D.; Herrero, E.; Rodríguez, E.; López González, M. J.; Rodríguez López, C.; Cifuentes, C.; Mordasini, C.; Jeffers, S. V.; Rix, H. W.; Ofir, A.; Kürster, M.; Henning, T.; Emsenhuber, A.; Passegger, V. M.; Abellán, F. J.; Rodríguez Trinidad, A.; Pedraz, S.; Aceituno, J.; Seifert, W.; Fernández Martín, A.; Zechmeister, M.; De Juan, E.; Perryman, M. A. C.; Antona, R.; Alonso Floriano, F. J.; Ferro, I. M.; Johnson, E. N.; Labiche, N.; Rebolo, R.; Becerril Jarque, S.; Azzaro, M.; Fuhrmeister, B.; Lizon, J. L.; Perger, M.; Brinkmöller, M.; Berdiñas, Z. M.; Galadí Enríquez, D.; López Santiago, J.; Cortés Contreras, M.; Calvo Ortega, R.; Del Burgo, C.; Gallardo Cava, I.; Rosich, A.; Cardona Guillén, C.; Cano, J.; García Vargas, M. L.; Amado, P. J.; Casanova, V.; Carro, J.; García Piquer, A.; Kaminski, A.; Chaturvedi, P.; Gesa, L.; Abril, M.; Claret, A.; González Álvarez, E.; Ammler von Eiff, M.; Czesla, S.; Barrado, D.; Dorda, R.; González Peinado, R.; Fernández Hernández, Maite; Klüter, J.; Kim, M.; Lara, L. M.; Lampón, M.; López del Fresno, M.; Lodieu, N.; Mancini, L.; Mall, U.; Martín Fernández, P.; Mirabet, E.; Nortmann, L.; Pallé, E.; Caballero, J. A.; Huke, P.; Huber, A.; Holgado, G.; Klutsch, A.; Launhardt, R.; López Salas, F. J.; Stürmer, J.; Suárez, J. C.; Tabernero, H.; Tulloch, S. M.; Veredas, G.; Vico Linares, J. I.; Vilardell, F.; Wagner, K.; Winkler, J.; Wolthoff, V.; Sánchez López, A.; Sánchez Blanco, E.; Sadegi, S.; Labarga, F.; Marfil, E.; Casasayas Barris, N.; Bergond, G.; Martín, E. L.; Mandel, H.; Sarkis, P.; Lázaro, F. J.; Luque, R.; Burn, R.; Marvin, E. L.; Martín Ruiz, S.; Sarmiento, L. F.; González Cuesta, L.; Anglada Escudé, G.; Cárdenas, M. C.; Nelson, R. P.; Moya, A.; Schäfer, S.; Reffert, S.; Casal, E.; Pascual, J.; Nowak, G.; Schlecker, M.; Quirrenbach, A.; Kemmer, J.; Pérez Medialdea, D.; Pavlov, A.; Schmitt, J. H. M. M.; Lalitha, S.; Rabaza, O.; Pérez Calpena, A.; Schöfer, P.; Llamas, M.; Redondo, P.; Ramón Ballesta, A.; Magán Madinabeitia, H.; Rodler, F.; Sota, A.; Marín Molina, J. A.; Sabotta, S.; Stahl, O.; Martínez Rodríguez, H.; Salz, M.; Stock, S.; Naranjo, V.; Sánchez Carrasco, M. A.; Stuber, T.; Sanz Forcada, J.; Johansen, A.; Baroch, D.; Lafarga, M.; Dreizler, S.; Tal Or, L.; Schweitzer, A.; Hagen, H. J.; Guenther, E. W.; Montes, D.; Aceituno, Francisco José; Arroyo Torres, B.; Benítez, D.; Kehr, M.; Béjar, V. J. S.; Zapatero Osorio, M. R.; Yan, F.; Klahr, H.; Nagel, E.; Trifonov, T.; Guàrdia, J.; Guijarro, A.; De Guindos, E.; Hatzes, A. P.; Hauschildt, P. H.; Hedrosa, R. P.; Hermelo, I.; Hernández Arabi, R.; Hernández Otero, F.; Hintz, D.; Díez Alonso, E.; Colomé, J.; González Hernández, Carmen; Solano, Enrique; Israel Science Foundation (ISF); Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT); Swiss National Science Foundation (SNSF); Deutsches Zentrum für Luft- und Raumfahrt (DLR); Ministero dell'Istruzione, dell'Università e della Ricerca (MIUR); European Research Council (ERC); Generalitat de Catalunya; Deutsche Forschungsgemeinschaft (DFG); Queen Mary University of London; Consejo Nacional de Ciencia y Tecnología (CONACYT); Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737; Morales, J. C. [0000-0003-0061-518X]; Mustill, A. J. [0000-0002-2086-3642]; Ribas, I. [0000-0002-6689-0312]; Davies, M. B. [0000-0001-6080-1190]; Bauer, F. F. [0000-0003-1212-5225]; Herrrero, E. [0000-0001-8602-6639]; Rodríguez, E. [0000-0001-6827-9077]; López González, M. J. [0000-0001-8104-5128]; Rodríguez López, C. [0000-0001-5559-7850]; López González, M. J. [0000-0001-8104-5128]; Rodríguez López, C. [0000-0001-5559-7850]; Luque, R. [0000-0002-4671-2957]; López Santiago, J. [0000-0003-2402-8166]; Perger, M. [0000-0001-7098-0372]; Guenther, E. W. [0000-0002-9130-6747]; Schmitt, J. H. M. M. [0000-0003-2554-9916]; Mordasini, C. [0000-0002-1013-2811]; Aceituno, J. [0000-0003-0487-1105]; Stock, S. [0000-0002-1166-9338]; Lafarga, M. [0000-0002-8815-9416]; Nagel, E. [0000-0002-4019-3631]; Barrado, D. [0000-0002-5971-9242]; Tulloch, S. [0000-0003-0840-8521]; Rosich, A. [0000-0002-9141-3067]; Trifonov, T. [0000-0002-0236-775X]; Bergond, G. [0000-0003-3132-9215]; Zapatero Osorio, M. R. [0000-0001-5664-2852]; Kaminski, A. [0000-0003-0203-8208]; Montes, D. [0000-0002-7779-238X]; Cano, J. [0000-0003-1984-5401]; Baroch, D. [0000-0001-7568-5161]; Alonso Floriano, F. J. [0000-0003-1202-5734]; Sabotta, S. [0000-0001-9078-5574]; Ammler-von Eiff, M. [0000-0001-9565-1698]; Chaturvedi, P. [0000-0002-1887-1192]; Anglada Escudé, G. [0000-0002-3645-5977]; Becerril Jarque, S. [0000-0001-9009-1150]; Díez Alonso, E. [0000-0002-5826-9892]; Passegger, V. M. [0000-0002-8569-7243]; Burn, R. [0000-0002-9020-7309]; García Vargas, M. L. [0000-0002-2058-3528]; Amado, P. J. [0000-0002-8388-6040]; Cardona Guillén, C. [0000-0002-2198-4200]; Carro, J. [0000-0002-0838-3603]; Guàrdia, J. [0000-0002-7191-9001]; Abellán, F. J. [0000-0002-5724-1636]; Cifuentes, C. [0000-0003-1715-5087]; Colomé, J. [0000-0002-1678-2241]; Hermelo, I. [0000-0001-9178-694X]; Arroyo Torres, B. [0000-0002-3392-4694]; Emsenhuber, A. [0000-0002-8811-1914]; Fuhrmeister, B. [0000-0001-8321-5514]; Johnson, E. [0000-0003-2260-5134]; Berdiñas, Z. M. [0000-0002-6057-6461]; González Álvarez, E. [0000-0002-4820-2053]; González Cuesta, L. [0000-0002-1241-5508]; González Hernández, J. I. [0000-0002-0264-7356]; Klüter, J. [0000-0002-3469-5133]; Calvo Ortega, R. [0000-0003-3693-6030]; Guijarro, A. [0000-0001-5518-1759]; Lara, L. M. [0000-0002-7184-920X]; Casasayas Barris, N. [0000-0002-2891-8222]; Hintz, D. [0000-0002-5274-2589]; López del Fresno, M. [0000-0002-9479-7780]; Czesla, S. [0000-0002-4203-4773]; De Juan Fernández, E. [0000-0002-9382-4505]; Kehr, M. [0000-0002-7420-7368]; Marín Molina, J. A. [0000-0002-3525-0806]; Galadí Enríquez, D. [0000-0003-4946-5653]; Klutsch, A. [0000-0001-7869-3888]; Labarga, F. [0000-0002-7143-0206]; Martínez Rodríguez, H. [0000-0002-1919-228X]; González Peinado, R. [0000-0002-6658-8930]; Launhardt, R. [0000-0002-8298-2663]; Lizon, J. L. [0000-0001-8928-2566]; Naranjo, V. [0000-0003-0097-1061]; De Guindos, E. [0000-0002-8124-9101]; Magan Madinabeitia, H. [0000-0003-1243-4597]; Aceituno, F. J. [0000-0001-8074-4760]; Manici, L. [0000-0002-9428-8732]; Ofir, A. [0000-0002-9152-5042]; Huke, P. [0000-0001-5913-2743]; Martín, E. [0000-0002-1208-4833]; Rabaza, O. [0000-0003-2766-2103]; Kim, M. [0000-0001-6218-2004]; Marvin, C. J. [0000-0002-2249-2611]; Rodríguez Trinidad, A. [0000-0002-3356-8634]; Lampón, M. [0000-0002-0183-7158]; Nelson, R. [0000-0002-9687-8779]; Nortmann, L. [0000-0001-8419-8760]; Sanz Forcada, J. [0000-0002-1600-7835]; Lodieu, N. [0000-0002-3612-8968]; Pascual Granado, J. [0000-0003-0139-6951]; Pedraz, S. [0000-0003-1346-208X]; Schäfer, S. [0000-0001-8597-8048]; Marfil, E. [0000-0001-8907-4775]; Ramón Ballesta, A. [0000-0002-4323-0610]; Redondo, P. G. [0000-0001-5992-5778]; Schöfer, P. [0000-0002-5969-3708]; Martín Ruiz, S. [0000-0002-9006-7182]; Sadegi, S. [0000-0001-9897-6121]; García Piquer, A. [0000-0002-6872-4262]; Sánchez Carrasco, M. A. [0000-0001-5533-3660]; Stuber, T. [0000-0003-2185-0525]; Moya, A. [0000-0003-1665-5389]; Sarkis, P. [0000-0001-8128-3126]; Vilardell, F. [0000-0003-0441-1504]; Nowak, G. [0000-0002-7031-7754]; Schlecker, M. [0000-0001-8355-2107]; Béjar, V. J. S. [0000-0002-5086-4232]; Pérez Calpena, A. [0000-0001-7361-9240]; Solano, E. [0000-0003-1885-5130]; Sota, A. [https://orcid.org/0000-0002-9404-6952]; Klahr, H. [0000-0002-8227-5467]; Rodler, F. [0000-0003-0650-5723]; Suárez, J. C. [0000-0003-3649-8384]; Tabernero, H. [0000-0002-8087-4298]; Cortés Contreras, M. [0000-0003-3734-9866]; Sánchez López, A. [0000-0002-0516-7956]; Winkler, J. [0000-0003-0568-8820]; Yan, F. [0000-0001-9585-9034]; Reffert, S. [0000-0002-0460-8289]; Sarmiento, L. F. [0000-0002-8475-9705]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737; Centros de Excelencia Severo Ochoa, INSTITUTO DE ASTROFISICA DE ANDALUCIA (IAA), SEV-2017-0709
Surveys have shown that super-Earth and Neptune-mass exoplanets are more frequent than gas giants around low-mass stars, as predicted by the core accretion theory of planet formation. We report the discovery of a giant planet around the very-low-mass star GJ 3512, as determined by optical and near-infrared radial-velocity observations. The planet has a minimum mass of 0.46 Jupiter masses, very high for such a small host star, and an eccentric 204-day orbit. Dynamical models show that the high eccentricity is most likely due to planet-planet interactions. We use simulations to demonstrate that the GJ 3512 planetary system challenges generally accepted formation theories, and that it puts constraints on the planet accretion and migration rates. Disk instabilities may be more efficient in forming planets than previously thought.Copyright © 2019 The Authors, some rights reserved; exclusive licensee American Association for the Advancement of Science

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