Examinando por Autor "Nielsen, L. D."

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Acceso Abierto
A hot mini-Neptune in the radius valley orbiting solar analogue HD 110113
(Oxford Academics: Oxford University Press, 2021-01-25) Osborn, Hugh P.; Armstrong, D. J.; Adibekyan, V.; Collins, K. A.; Delgado Mena, E.; Howell, Steve B.; Hellier, C.; King, G. W.; Lillo Box, J.; Nielsen, L. D.; Otegi, J. F.; Santos, N. C.; Ziegler, C.; Anderson, D. R.; Briceño, C.; Burke, C. J.; Bayliss, D.; Barrado, D.; Bryant, E. M.; Brown, D. J. A.; Barros, S. C. C.; Bouchy, F.; Caldwell, D. A.; Conti, D.; Díaz, R. F.; Dragomir, D.; Deleuil, M.; Demanegon, O. D. S.; Dorn, C.; Daylan, T.; Figueira, P.; Helled, R.; Hoyer, S.; Jenkins, J. S.; Jensen, E. L. N.; Latham, D. W.; Law, N.; Louie, D.; Mann, A. W.; Osborn, A.; Pollacco, D.; Rodríguez, D. R.; Rackham, B. V.; Ricker, G.; Scott, N. J.; Sousa, S. G.; Seager, S.; Stassun, K. G.; Smith, J. C.; Strom, P.; Udry, S.; Villaseñor, J. N.; Vanderspek, R.; West, R.; Wheatley, P. J.; Winn, J. N.; Fundacao para a Ciencia e a Tecnologia (FCT); Science and Technology Facilities Council (STFC); Agencia Estatal de Investigación (AEI); National Aeronautics and Space Administration (NASA); UK Space Agency; Dorn, C. [0000-0001-6110-4610]; Anderson, D. [0000-0001-7416-7522]; Barros, S. [0000-0003-2434-3625]; Adibekyan, V. [0000-0002-0601-6199]; Armstrong, D. [0000-0002-5080-4117]; Santos, N. [0000-0003-4422-2919]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We report the discovery of HD 110113 b (TESS object of interest-755.01), a transiting mini-Neptune exoplanet on a 2.5-d orbit around the solar-analogue HD 110113 (Teff = 5730 K). Using TESS photometry and High Accuracy Radial velocity Planet Searcher (HARPS) radial velocities gathered by the NCORES program, we find that HD 110113 b has a radius of 2.05 ± 0.12 R⊕ and a mass of 4.55 ± 0.62 M⊕. The resulting density of 2.90+0.75−0.59 g cm−3 is significantly lower than would be expected from a pure-rock world; therefore HD 110113 b must be a mini-Neptune with a significant volatile atmosphere. The high incident flux places it within the so-called radius valley; however, HD 110113 b was able to hold on to a substantial (0.1–1 per cent) H–He atmosphere over its ∼4 Gyr lifetime. Through a novel simultaneous Gaussian process fit to multiple activity indicators, we were also able to fit for the strong stellar rotation signal with period 20.8 ± 1.2 d from the RVs and confirm an additional non-transiting planet, HD 110113 c, which has a mass of 10.5 ± 1.2 M⊕ and a period of 6.744+0.008−0.009 d.
Restringido
A remnant planetary core in the hot-Neptune desert
(Springer Nature Research Journals, 2020-07-01) Armstrong, D. J.; López, T. A.; Adibekyan, V.; Booth, R. A.; Bryant, E. M.; Collins, K. A.; Deleuil, M.; Emsenhuber, A.; Huang, C. X.; King, G. W.; Lillo Box, J.; Lissauer, J. J.; Matthews, E.; Mousis, O.; Nielsen, L. D.; Osborn, Hugh P.; Otegi, J.; Santos, N. C.; Sousa, S. G.; Stassun, K. G.; Veras, D.; Ziegler, C.; Acton, J. S.; Almenara, J. M.; Anderson, D. R.; Barrado, D.; Barros, S. C. C.; Bayliss, D.; Belardi, C.; Bouchy, F.; Briceño, C.; Brogi, M.; Brown, D. J. A.; Burleigh, M. R.; Casewell, S. L.; Chausev, A.; Ciardi, D. R.; Collins, K. I.; Colón, K. D.; Cooke, B. F.; Crossfield, J. M.; Díaz, R. F.; Delgado Mena, E.; Gandhi, O. D. S.; Gill, Samuel; Gonzales, E. J.; Goad, M. R.; Günther, M. N.; Helled, R.; Hojjatpanah, S.; Howell, Steve B.; Jackman, J.; Jenkins, J. S.; Jenkins, J. M.; Jensen, E. L. N.; Kennedy, G. M.; Latham, D. W.; Law, N.; Osborn, M.; Pollacco, D.; Queloz, D.; Raynard, L.; Ricker, G. R.; Rowden, P.; Santerne, A.; Schlieder, J. E.; Seager, S.; Sha, L.; Tan, T. G.; Tilbrook, R. H.; Ting, E.; Udry, S.; Vanderspek, R.; Watson, C. A.; West, R. G.; Wilson, P. A.; Winn, J. N.; Wheatley, P.; Villaseñor, J. N.; Vines, J. I.; Zhan, Z.; National Aeronautics and Space Administration (NASA); Fundação para a Ciência e a Tecnologia (FCT); Agencia Estatal de Investigación (AEI); Science and Technology Facilities Council (STFC); Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT); Collins, K. A. [0000-0002-4317-142X]; Lillo Box, J. [0000-0003-3742-1987]; Matthews, E. [0000-0003-0593-1560]; Sousa, S. [0000-0002-3631-6440]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The interiors of giant planets remain poorly understood. Even for the planets in the Solar System, difficulties in observation lead to large uncertainties in the properties of planetary cores. Exoplanets that have undergone rare evolutionary processes provide a route to understanding planetary interiors. Planets found in and near the typically barren hot-Neptune 'desert'(1,2)(a region in mass-radius space that contains few planets) have proved to be particularly valuable in this regard. These planets include HD149026b(3), which is thought to have an unusually massive core, and recent discoveries such as LTT9779b(4)and NGTS-4b(5), on which photoevaporation has removed a substantial part of their outer atmospheres. Here we report observations of the planet TOI-849b, which has a radius smaller than Neptune's but an anomalously large mass of39.1-2.6+2.7Earth masses and a density of5.2-0.8+0.7grams per cubic centimetre, similar to Earth's. Interior-structure models suggest that any gaseous envelope of pure hydrogen and helium consists of no more than3.9-0.9+0.8 per cent of the total planetary mass. The planet could have been a gas giant before undergoing extreme mass loss via thermal self-disruption or giant planet collisions, or it could have avoided substantial gas accretion, perhaps through gap opening or late formation(6). Although photoevaporation rates cannot account for the mass loss required to reduce a Jupiter-like gas giant, they can remove a small (a few Earth masses) hydrogen and helium envelope on timescales of several billion years, implying that any remaining atmosphere on TOI-849b is likely to be enriched by water or other volatiles from the planetary interior. We conclude that TOI-849b is the remnant core of a giant planet.
Acceso Abierto
HD 213885b: a transiting 1-d-period super-Earth with an Earth-like composition around a bright (V = 7.9) star unveiled by TESS .
(Oxford Academics: Blackwell Publishing, 2020-01-15) Espinoza, N.; Brahm, R.; Henning, T.; Jordán, A.; Dorn, C.; Rojas, F.; Sarkis, P.; Kossakowski, D.; Schlecker, M.; Díaz, M. R.; Jenkins, J. S.; Aguilera Gómez, C.; Jenkins, J. M.; Twicken, J. D.; Collins, K. A.; Lissauer, J. J.; Armstrong, D. J.; Adibekyan, V.; Barrado, D.; Barros, S. C. C.; Battley, M.; Bayliss, D.; Bouchy, F.; Bryant, E. M.; Cooke, B. F.; Demangeon, O. D. S.; Dumusque, X.; Figueira, P.; Giles, H.; Lillo Box, J.; Lovis, C.; Nielsen, L. D.; Pepe, F.; Pollacco, D.; Santos, N. C.; Sousa, S. G.; Udry, S.; Wheatley, P. J.; Turner, O.; Marmier, M.; Ségransan, D.; Ricker, G.; Latham, D.; Seager, S.; Winn, J. N.; Kielkopf, J. F.; Hart, R.; Wingham, G.; Jensen, E. L. N.; Helminiak, K. G.; Tokovinin, A.; Briceño, C.; Ziegler, C.; Law, N. M.; Mann, A. W.; Daylan, T.; Doty, J. P.; Guerrero, N.; Boyd, P.; Crossfield, I.; Morris, Robert L.; Henze, C. E.; Dean Chacon, A.; Comisión Nacional de Investigación Científica y Tecnológica (CONICYT); Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT); Science and Technology Facilities Council (STFC); Swiss National Science Foundation (SNSF); Fundacao para a Ciencia e a Tecnologia (FCT); National Science Centre, Poland (NCN); Millennium Institute of Astrophysics (MAS); Barrado, D. [https://orcid.org/0000-0002-5971-9242]; Lillo Box, J. [https://orcid.org/0000-0003-3742-1987]; Díaz, M. [https://orcid.org/0000-0002-2100-3257]; Wheatley, P. [https://orcid.org/0000-0003-1452-2240]; Nielsen, L. D. [https://orcid.org/0000-0002-5254-2499]; Figueira, P. [https://orcid.org/0000-0001-8504-283X]; Jenssen, E. [https://orcid.org/0000-0002-4625-7333]; Barros, S. [https://orcid.org/0000-0003-2434-3625]; Espinoza Pérez, N. [https://orcid.org/0000-0001-9513-1449]; Armstrong, D. J. [https://orcid.org/0000-0002-5080-4117]; Bayliss, D. [https://orcid.org/0000-0001-6023-1335]; Turner, O. [https://orcid.org/0000-0002-8216-2796]; Sousa, S. G. [https://orcid.org/0000-0001-9047-2965]; Kielpof, J. F. [https://orcid.org/0000-0003-0497-2651]
We report the discovery of the 1.008-d, ultrashort period (USP) super-EarthHD213885b (TOI141b) orbiting the bright (V= 7.9) star HD 213885 (TOI-141, TIC 403224672), detected using photometry from the recently launched TESS mission. Using FEROS, HARPS, and CORALIE radial velocities, we measure a precise mass of 8.8 +/- 0.6M. for this 1.74 +/- 0.05 R. exoplanet, which provides enough information to constrain its bulk composition - similar to Earth's but enriched in iron. The radius, mass, and stellar irradiation of HD 213885b are, given our data, very similar to 55 Cancri e, making this exoplanet a good target to perform comparative exoplanetology of short period, highly irradiated super-Earths. Our precise radial velocities reveal an additional 4.78-d signal which we interpret as arising from a second, non-transiting planet in the system, HD 213885c, whoseminimum mass of 19.9 +/- 1.4M. makes it consistent with being a Neptune-mass exoplanet. The HD 213885 system is very interesting from the perspective of future atmospheric characterization, being the second brightest star to host an USP transiting super-Earth (with the brightest star being, in fact, 55 Cancri). Prospects for characterization with present and future observatories are discussed.
Acceso Abierto
Mass determinations of the three mini-Neptunes transiting TOI-125
(Oxford Academics: Oxford University Press, 2020-01-23) Nielsen, L. D.; Gandolfi, D.; Armstrong, D. J.; Jenkins, J. S.; Fridlund, M.; Santos, N. C.; Dai, F.; Adibekyan, V.; Luque, R.; Steffen, J. H.; Esposito, M.; Meru, F.; Sabotta, S.; Bolmont, É.; Kossakowski, D.; Otegi, J. F.; Murgas Alcaino, F.; Stalport, M.; Rodler, F.; Díaz, M. R.; Kurtovic, N. T.; Ricker, G.; Vanderspek, R.; Latham, D. W.; Seager, S.; Winn, J. N.; Jenkins, J. M.; Allart, R.; Almenara, J. M.; Barrado, D.; Barros, S. C. C.; Bayliss, D.; Berdiñas, Z. M.; Boisse, I.; Bouchy, F.; Boyd, P.; Brown, D. J. A.; Bryant, E. M.; Burke, C. J.; Cochran, W. D.; Cooke, B. F.; Demangeon, O. D. S.; Díaz, R. F.; Dittman, J.; Dorn, C.; Dumusque, X.; García, R. A.; González Cuesta, L.; Georgieva, I.; Guerrero, N.; Hatzes, A. P.; Helled, R.; Henze, C. E.; Hojjatpanah, S.; Korth, J.; Lam, K. W. F.; Lillo Box, J.; López, T. A.; Livingston, J.; Mathur, S.; Mousis, O.; Narita, N.; Osborn, Hugh P.; Pallé, E.; Peña Rojas, P. A.; Persson, C. M.; Quinn, S. N.; Rauer, H.; Redfield, S.; Santerne, A.; Dos Santos, L. A.; Seidel, J. V.; Sousa, S. G.; Ting, E. B.; Turbet, M.; Udry, S.; Vanderburg, A.; Van Eylen, V.; Vines, J. I.; Wheatley, P. J.; Wilson, P. A.; Fondo Nacional de Desarrollo Científico y Tecnológico (FONDECYT); Swiss National Science Foundation (SNSF); Deutsche Forschungsgemeinschaft (DFG); Agencia Estatal de Investigación (AEI); European Southern Observatory (ESO); Swiss National Centre of Competence inResearch (NCCR); National Aeronautics and Space Administration (NASA); Fundacao para a Ciencia e a Tecnologia (FCT); European Research Council (ERC); Vanderburg, A. [0000-0001-7246-5438]; Dos Santos, L. [0000-0002-2248-3838]; Barrado, D. [0000-0002-5971-9242]; Cochran, W. [0000-0001-9662-3496]; Lillo Box, J. [0000-0003-3742-1987]; Barros, S. [0000-0003-2434-3625]; Stalport, M. [0000-0003-0996-6402]; Dorn, C. [0000-0001-6110-4610]; Nielsen, L. D. [0000-0002-5254-2499]; Seidel, J. V. [0000-0002-7990-9596]; Diaz, M. R. [0000-0002-2100-3257]; Bolmont, E. [0000-0001-5657-4503]; Adibekyan, V. [0000-0002-0601-6199]; Van Eylen, V. [0000-0001-5542-8870]; Armstrong, D. [0000-0002-5080-4117]; Korth, J. [0000-0002-0076-6239]; Díaz, R. [0000-0001-9289-5160]; Santos, N. [0000-0003-4422-2919]; Luque, R. [0000-0002-4671-2957]; Turbet, M. [0000-0003-2260-9856]; Mathur, S. [0000-0002-0129-0316]; Strom, P. A. [0000-0002-7823-1090]; Sabotta, S. [0000-0001-9078-5574]; Wheatley, P. [0000-0003-1452-2240]; Hojjatpanah, S. [0000-0002-0417-1902]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
The Transiting Exoplanet Survey Satellite, TESS, is currently carrying out an all-sky search for small planets transiting bright stars. In the first year of the TESS survey, a steady progress was made in achieving the mission's primary science goal of establishing bulk densities for 50 planets smaller than Neptune. During that year, the TESS's observations were focused on the southern ecliptic hemisphere, resulting in the discovery of three mini-Neptunes orbiting the star T01-125, a V = 11,0 KO dwarf. We present intensive HARPS radial velocity observations, yielding precise mass measurements for TO1-125b, TOI-125c, and TOI-125d. TOI-125b has an orbital period of 4,65 d, a radius of 2,726 + 0,075 RE, a mass of 9,50 0,88 ME, and is near the 2:1 mean motion resonance with TOI-125c at 9.15 d. TOI-125c has a similar radius of 2,759 0.10 RE and a mass of 6,63 + 0,99 ME, being the puffiest of the three planets. T01-125d has an orbital period of 19,98 d and a radius of 2.93 + 0,17 RE and mass 13,6 1,2 ME, For T01-125b and d, we find unusual high eccentricities of 0.19 0.04 and 0.17+(c):(!,(, respectively. Our analysis also provides upper mass limits for the two low-SNR planet candidates in the system; for T01-125.04 (Rp = 1.36 RE, P = 0.53 d), we find a 2a upper mass limit of 1.6 ME, whereas T01-125.05 (RP = 4.2-'2E44 RE, P = 13.28 d) is unlikely a viable planet candidate with an upper mass limit of 2.7 ME. We discuss the internal structure of the three confirmed planets, as well as dynamical stability and system architecture for this intriguing exoplanet system.
Acceso Abierto
Masses for the seven planets in K2-32 and K2-233 Four diverse planets in resonant chain and the first young rocky worlds
(EDP Sciences, 2020-08-11) Lillo Box, J.; López, T. A.; Santerne, A.; Nielsen, L. D.; Barros, S. C. C.; Deleuil, M.; Acuña, L.; Mousis, O.; Sousa, S. G.; Adibekyan, V.; Armstrong, D. J.; Barrado, D.; Bayliss, D.; Brown, D. J. A.; Demangeon, O. D. S.; Dumusque, X.; Figueira, P.; Hojjatpanah, S.; Osborn, Hugh P.; Santos, N. C.; Udry, S.; Science and Technology Facilities Council (STFC); Agencia Estatal de Investigación (AEI); Fundacao para a Ciencia e a Tecnologia (FCT); Lillo Box, J. [0000-0003-3742-1987]; López, T. [0000-0001-6622-1250]; Santerne, A. [0000-0002-3586-1316]; Barros, S. [0000-0003-2434-3625]; Deleuil, M. [0000-0001-6036-0225]; Sousa, S. G. [0000-0001-9047-2965]; Adibekyan, V. [0000-0002-0601-6199]; Armstrong, D. J. [0000-0002-5080-4117]; Barrado, D. [0000-0002-5971-9242]; Bayliss, D. [0000-0001-6023-1335]; Brown, D. J. A. [0000-0003-1098-2442]; Demangeon, O. D. S. [0000-0001-7918-0355]; Dumusque, X. [0000-0002-9332-2011]; Figueira, P. [0000-0001-8504-283X]; Hojjatpanah, S. [0000-0002-0417-1902]; Osborn, H. [0000-0002-4047-4724]; Santos, N. C. [0000-0003-4422-2919]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
Context. High-precision planetary densities are key pieces of information necessary to derive robust atmospheric properties for extrasolar planets. Measuring precise masses is the most challenging part of this task, especially in multi-planetary systems. The ESO-K2 collaboration focuses on the follow-up of a selection of multi-planetary systems detected by the K2 mission using the HARPS instrument with this goal in mind. Aims. In this work, we measure the masses and densities of two multi-planetary systems: a four-planet near resonant chain system (K2-32) and a young (~400 Myr old) planetary system consisting of three close-in small planets (K2-233). Methods. We obtained 199 new HARPS observations for K2-32 and 124 for K2-233 covering a long baseline of more than three years. We performed a joint analysis of the radial velocities and K2 photometry with PASTIS to precisely measure and constrained the properties of these planets, focusing on their masses and orbital properties. Results. We find that K2-32 is a compact scaled-down version of the Solar System’s architecture, with a small rocky inner planet (Me = 2.1−1.1+1.3 M⊕, Pe ~ 4.35 days) followed by an inflated Neptune-mass planet (Mb = 15.0−1.7+1.8 M⊕, Pb ~ 8.99 days) and two external sub-Neptunes (Mc = 8.1 ± 2.4 M⊕, Pc ~ 20.66 days; Md = 6.7 ± 2.5 M⊕, Pd ~ 31.72 days). K2-32 becomes one of the few multi-planetary systems with four or more planets known where all have measured masses and radii. Additionally, we constrain the masses of the three planets in the K2-233 system through marginal detection of their induced radial velocity variations. For the two inner Earth-size planets we constrain their masses at a 95% confidence level to be smaller than Mb < 11.3 M⊕ (Pb ~ 2.47 days), Mc < 12.8 M⊕ (Pc ~ 7.06 days). The outer planet is a sub-Neptune size planet with an inferred mass of Md = 8.3−4.7+5.2 M⊕ (Md < 21.1 M⊕, Pd ~ 24.36 days). Conclusions. Our observations of these two planetary systems confirm for the first time the rocky nature of two planets orbiting a young star, with relatively short orbital periods (<7 days). They provide key information for planet formation and evolution models of telluric planets. Additionally, the Neptune-like derived masses of the three planets, K2-32 b, c, d, puts them in a relatively unexplored regime of incident flux and planet mass, which is key for transmission spectroscopy studies in the near future.
Acceso Abierto
Three planets transiting the evolved star EPIC 249893012: A hot 8.8-M super-Earth and two warm 14.7 and 10.2-M sub-Neptunes
(EDP Sciences, 2020-04-24) Hidalgo, D.; Pallé, E.; Alonso, R.; Gandolfi, D.; Fridlund, M.; Nowak, G.; Luque, R.; Hirano, T.; Justesen, A. B.; Cochran, W. D.; Barragán, O.; Spina, L.; Rodler, F.; Albrecht, S.; Anderson, D.; Amado, P. J.; Bryant, E.; Caballero, J. A.; Cabrera, J.; Csizmadia, Sz.; Dai, F.; De Leon, J.; Deeg, H. J.; Eigmuller, Ph.; Endl, M.; Erikson, A.; Esposito, M.; Figueira, P.; Georgieva, I.; Grziwa, S.; Guenther, E. W.; Hatzes, A. P.; Hjorth, M.; Hoeijmakers, H. J.; Kabath, P.; Korth, J.; Kuzuhara, M.; Lafarga, M.; Lampón, M.; Leao, I. C.; Livingston, J.; Mathur, S.; Montañés Rodríguez, P.; Morales, J. C.; Murgas Alcaino, F.; Nagel, E.; Narita, N.; Nielsen, L. D.; Patzold, M.; Persson, C. M.; Prieto Arranz, J.; Quirrenbach, A.; Rauer, H.; Redfield, S.; Reiners, A.; Ribas, I.; Smith, A. M. S.; Subjak, J.; Van Eylen, V.; Wilson, P. A.; Ministerio de Economía y Competitividad (MINECO); Agencia Estatal de Investigación (AEI); Deutsche Forschungsgemeinschaft (DFG); Japan Science and Technology Agency (JST); Hidalgo, D. [0000-0002-7340-6963]; Unidad de Excelencia Científica María de Maeztu Centro de Astrobiología del Instituto Nacional de Técnica Aeroespacial y CSIC, MDM-2017-0737
We report the discovery of a new planetary system with three transiting planets, one super-Earth and two sub-Neptunes, that orbit EPIC 249893012, a G8 IV-V evolved star ( M ? = 1.05 0.05 M fi, R ? = 1.71 0.04 R fi, Te ff = 5430 85 K). The star is just leaving the main sequence. We combined K2 photometry with IRCS adaptive-optics imaging and HARPS, HARPS-N, and CARMENES highprecision radial velocity measurements to confirm the planetary system, determine the stellar parameters, and measure radii, masses, and densities of the three planets. With an orbital period of 3:5949+0:0007 0:0007 days, a mass of 8:75+1:09 1:08 M , and a radius of 1:95+0:09 0:08 R , the inner planet b is compatible with nickel-iron core and a silicate mantle ( b = 6:39+1:19 1:04 g cm 3). Planets c and d with orbital periods of 15:624+0:001 0:001 and 35:747+0:005 0:005 days, respectively, have masses and radii of 14:67+1;84 1:89 M and 3:67+0:17 0:14 R and 10:18+2:46 2:42 M and 3:94+0:13 0:12 R , respectively, yielding a mean density of 1:62+0:30 0:29 and 0:91+0:25 0:23 g cm 3, respectively. The radius of planet b lies in the transition region between rocky and gaseous planets, but its density is consistent with a rocky composition. Its semimajor axis and the corresponding photoevaporation levels to which the planet has been exposed might explain its measured density today. In contrast, the densities and semimajor axes of planets c and d suggest a very thick atmosphere. The singularity of this system, which orbits a slightly evolved star that is just leaving the main sequence, makes it a good candidate for a deeper study from a dynamical point of view.