Proyecto de Investigación: JETS ESTELARES, DISCOS Y CAMPOS MAGNETICOS. CIENCIA PARA EL SKA Y CONTRIBUCION AL DISEÑO DE PHASED ARRAY FEEDS
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AYA2017-84390-C2-1-R
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The morpho-kinematical structure and chemical abundances of the complex planetary nebula NGC 1514
(Oxford Academics: Oxford University Press, 2021-04-30) Aller, A.; Vázquez, R.; Olguín, L.; Miranda, L. F.; Ressler, M. E.; Comunidad de Madrid; Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT); 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
We present high-resolution, long-slit optical spectra and images of the planetary nebula NGC 1514. The position velocity maps of the [O III] emission line reveal complex kinematics with multiple structures. A morpho-kinematical analysis suggests an inner shell, originally spherical and now distorted by several bubbles, and an attached outer shell. The two well-defined, mid-infrared rings of NGC 1514 are not detected in our high-resolution, long-slit spectra, which prevented us from doing a kinematical analysis of them. Based exclusively on their morphology, we propose a barrel-like structure to explain the rings. Several ejection processes have been possibly involved in the formation of the nebula, although a time sequence is difficult to establish with the current data. We also analyse intermediate-resolution, long-slit spectra with the goal of studying the physical parameters and chemical abundances of NGC 1514. The nebular spectra reveal a moderate-excitation nebula with weak emission lines of [Ar III], [Ne III], He I, and He II. Neither [N II] nor other low-excitation emission lines are detected. We found an electron temperature around 14 000 K in the gas and an electron density in the range of 2000–4000 cm−3.
Planetary nebulae seen with TESS: Discovery of new binary central star candidates from Cycle 1
(EDP Sciences, 2020-03-24) Aller, A.; Lillo Box, J.; Jones, David; Miranda, L. F.; Barceló Forteza, S.; Comunidad de Madrid; Agencia Estatal de Investigación (AEI); 0000-0003-0884-9589; 0000-0003-3742-1987; 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
Context. It has become clear in recent years that binarity plays a crucial role in many aspects of planetary nebulae (PNe), particularly with regard to the striking morphologies they exhibit. To date, there are nearly 60 known binary central stars of PNe (bCSPNe). However, both theory and observation indicate that this figure represents only the tip of the iceberg, with the Galactic PN population hosting orders of magnitude more stars.
Aims. We are involved in a search for new bCSPNe with the aim of enhancing the statistical validation of the key role of binarity in the formation and shaping of PNe. New discoveries of bCSPNe and their characterization carry important implications not only for understanding PN evolution, but also for studying binary evolution and the common-envelope phase, which is still poorly understood.
Methods. We used data from the TESS satellite to search for variability in the eight CSPNe that belong to the two-minute cadence of preselected targets in Cycle 1, with their available pipeline-extracted light curves. We identified strong periodicities and analysed them in the context of the binary scenario.
Results. All the CSPNe but one (Abell 15) show clear signs of periodic variability in TESS. The cause of this variability can be attributed to different effects, some of them requiring the presence of a companion star. We find simple sinusoidal modulations in several of the systems, compatible with irradiation effects. In addition, two of the central stars (PG 1034+001 and NGC 5189) also show photometric variations due to ellipsoidal variations and other signs of variability that are probably caused by star spots or relativistic Doppler-beaming. The case of the well-studied Helix Nebula is of particular interest; here we constructed a series of binary models to explain the modulations we see in the light curve. We find that the variability constrains the possible companion to be very low-mass main-sequence star or sub-stellar object. We also identify, in substantial detail, the individual pulsation frequencies of NGC 246.
ALMA observations of the early stages of substellar formation in the Lupus 1 and 3 molecular clouds
(EDP Sciences, 2021-01-29) Santamaría Miranda, A.; De Gregorio Monsalvo, I.; Plunkett, A. L.; Huélamo, N.; López, C.; Ribas, Á.; Schreiber, M. R.; Muzic, K.; Palau, A.; Knee, L. B. G.; Bayo, A.; Comerón, F.; Hales, A.; Agencia Estatal de Investigación (AEI); Fundacao para a Ciencia e a Tecnologia (FCT); Consejo Nacional de Ciencia y Tecnología (CONACYT); Santamaría Miranda, A. [0000-0001-6267-2820]; De Gregorio Monsalvo, I. [0000-0003-4518-407X]; Plunkett, A. L. [0000-0002-9912-5705]; Huélamo, N. [0000-0002-2711-8143]; Ribas, Á. [0000-0003-3133-3580]; Schreiber, M. R. [0000-0003-3903-8009]; Muzic, K. [0000-0002-7989-2595]; Palau, A. [0000-0002-9569-9234]; Bayo, A. [0000-0001-7868-7031]; Comerón, F. [0000-0002-7838-2606]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. The dominant mechanism leading to the formation of brown dwarfs (BDs) remains uncertain. While the census of Class II analogs in the substellar domain continues to grow, the most direct keys to formation, which are obtained from younger objects (pre-BD cores and proto-BDs), are limited by the very low number statistics available.
Aims. We aim to identify and characterize a set of pre- and proto-BDs as well as Class II BDs in the Lupus 1 and 3 molecular clouds to test their formation mechanism.
Methods. We performed ALMA band 6 (1.3 mm) continuum observations of a selection of 64 cores previously identified from AzTEC/ASTE data (1.1 mm), along with previously known Class II BDs in the Lupus 1 and 3 molecular clouds. Surveyed archival data in the optical and infrared were used to complement these observations. We expect these ALMA observations prove efficient in detecting the youngest sources in these regions, since they probe the frequency domain at which these sources emit most of their radiation.
Results. We detected 19 sources from 15 ALMA fields. Considering all the pointings in our observing setup, the ALMA detection rate was ∼23% and the derived masses of the detected sources were between ∼0.18 and 124 MJup. We classified these sources according to their spectral energy distribution as 5 Class II sources, 2 new Class I/0 candidates, and 12 new possible pre-BD or deeply embedded protostellar candidates. We detected a promising candidate for a Class 0/I proto-BD source (ALMA J154229.778−334241.86) and inferred the disk dust mass of a bona fide Class II BD. The pre-BD cores might be the byproduct of an ongoing process of large-scale collapse. The Class II BD disks follow the correlation between disk mass and the mass of the central object that is observed at the low-mass stellar regime.
Conclusions. We conclude that it is highly probable that the sources in the sample are formed as a scaled-down version of low-mass star formation, although disk fragmentation may be responsible for a considerable fraction of BDs.
Tidal Interaction between the UX Tauri A/C Disk System Revealed by ALMA
(The Institute of Physics (IOP), 2020-06-19) Zapata, L.; Rodríguez, L. F.; Fernández López, M.; Palau, A.; Estalella, R.; Osorio, M.; Anglada, G.; Huélamo, N.; Consejo Nacional de Ciencia y Tecnología (CONACYT); Universidad Nacional Autónoma de México (UNAM); Agencia Estatal de Investigación (AEI); Zapata, L. [0000-0003-2343-7937]; Rodríguez, L. F. [0000-0003-2737-5681]; Palau, A. [0000-0002-9569-9234]; Fernández López, M. [0000-0001-5811-0454]; Estalella, R. [0000-0001-7341-8641]; Osorio, M. [0000-0002-6737-5267]; Anglada, G. [0000-0002-7506-5429]; Huelamo, N. [0000-0002-2711-8143]; 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
We present sensitive and high angular-resolution (similar to 02-03) (sub)millimeter (230 and 345 GHz) continuum and CO(2-1)/CO(3-2) line archive observations of the disk star system in UX Tauri carried out with the Atacama Large Millimeter/Submillimeter Array. These observations reveal the gas and dusty disk surrounding the young star UX Tauri A with a large signal-to-noise ratio (>400 in the continuum and >50 in the line), and for the first time we detect the molecular gas emission associated with the disk of UX Tauri C (with a size for the disk of <56 au). No (sub)millimeter continuum emission is detected at the 5 sigma level (0.2 mJy at 0.85 mm) associated with UX Tauri C. For the component UX Tauri C, we estimate a dust disk mass of <= 0.05M(circle plus). Additionally, we report a strong tidal disk interaction between both disks, UX Tauri A/C, separated 360 au in projected distance. The CO line observations reveal marked spiral arms in the disk of UX Tauri A and an extended redshifted stream of gas associated with the UX Tauri C disk. No spiral arms are observed in the dust continuum emission of UX Tauri A. Assuming a Keplerian rotation we estimate the enclosed masses (disk+star) from their radial velocities in 1.4 0.6Mfor UX Tauri A, and 70 30/siniJupiter masses for UX Tauri C (the latter coincides with the mass upper limit value for a brown dwarf). The observational evidence presented here lead us to propose that UX Tauri C has a close approach of a possible wide, evolving, and eccentric orbit around the disk of UX Tauri A, causing the formation of spiral arms and a stream of molecular gas falling toward UX Tauri C.
Bipolar molecular outflow of the very low-mass star Par-Lup3-4: Evidence for scaled-down low-mass star formation
(EDP Sciences, 2020-07-31) Santamaría Miranda, A.; De Gregorio Monsalvo, I.; Huélamo, N.; Plunkett, A. L.; Ribas, Á.; Comerón, F.; Chreiber, M. R.; López, C.; Muzic, K.; Testi, L.; Agencia Estatal de Investigación (AEI); 0000-0001-6267-2820; 0000-0003-4518-407X; 0000-0002-2711-8143; 0000-0002-9912-5705; 0000-0002-7838-2606; 0000-0003-3903-8009; 0000-0002-7989-2595; 0000-0003-1859-3070; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. Very low-mass stars are known to have jets and outflows, which is indicative of a scaled-down version of low-mass star formation. However, only very few outflows in very low-mass sources are well characterized.
Aims. We characterize the bipolar molecular outflow of the very low-mass star Par-Lup3-4, a 0.12 M-circle dot object known to power an optical jet.
Methods. We observed Par-Lup3-4 with ALMA in Bands 6 and 7, detecting both the continuum and CO molecular gas. In particular, we studied three main emission lines: CO(2-1), CO(3-2), and (CO)-C-13(3-2).
Results. Our observations reveal for the first time the base of a bipolar molecular outflow in a very low-mass star, as well as a stream of material moving perpendicular to the primary outflow of this source. The primary outflow morphology is consistent with the previously determined jet orientation and disk inclination. The outflow mass is 9.5 x 10(-7)M(circle dot), with an outflow rate of 4.3 x 10(-9)M(circle dot) yr(-1). A new fitting to the spectral energy distribution suggests that Par-Lup3-4 may be a binary system.
Conclusions. We have characterized Par-Lup3-4 in detail, and its properties are consistent with those reported in other very low-mass sources. This source provides further evidence that very low-mass sources form as a scaled-down version of low-mass stars.
