Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets: I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391

Autores
Jofré, Edgardo; Almenara, J.M.; Petrucci, Romina Paola; Diaz, Rodrigo Fernando; Gómez Maqueo Chew, Y.; Martioli, E.; Ramírez, I.; García, Luciano Héctor; Saffe, Carlos; Canul, E. F.; Buccino, Andrea Paola; Gómez, Marcos Javier; Moreno Hilario, E.
Año de publicación
2019
Idioma
inglés
Tipo de recurso
artículo
Estado
versión publicada
Descripción
Aims. Kepler-278 and Kepler-391 are two of the three evolved stars known to date on the red giant branch (RGB) to host multiple short-period transiting planets. Moreover, the planets orbiting Kepler-278 and Kepler-391 are among the smallest discovered around RGB stars. Here we present a detailed stellar and planetary characterization of these remarkable systems. Methods. Based on high-quality spectra from Gemini-GRACES for Kepler-278 and Kepler-391, we obtained refined stellar parameters and precise chemical abundances for 25 elements. Nine of these elements and the carbon isotopic ratios, 12C∕ 13C, had not previously been measured. Also, combining our new stellar parameters with a photodynamical analysis of the Kepler light curves, we determined accurate planetary properties of both systems. Results. Our revised stellar parameters agree reasonably well with most of the previous results, although we find that Kepler-278 is ~15% less massive than previously reported. The abundances of C, N, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, and Ce, in both stars, are consistent with those of nearby evolved thin disk stars. Kepler-391 presents a relatively high abundance of lithium (A(Li)NLTE = 1.29 ± 0.09 dex), which is likely a remnant from the main-sequence phase. The precise spectroscopic parameters of Kepler-278 and Kepler-391, along with their high 12C∕ 13C ratios, show that both stars are just starting their ascent on the RGB. The planets Kepler-278b, Kepler-278c, and Kepler-391c are warm sub-Neptunes, whilst Kepler-391b is a hot sub-Neptune that falls in the hot super-Earth desert and, therefore, it might be undergoing photoevaporation of its outer envelope. The high-precision obtained in the transit times allowed us not only to confirm Kepler-278c's TTV signal, but also to find evidence of a previously undetected TTV signal for the inner planet Kepler-278b. From the presence of gravitational interaction between these bodies we constrain, for the first time, the mass of Kepler-278b (Mp = 56 -13+37 M⊕ ) and Kepler-278c (Mp = 35 -21+9.9 M⊕ ). The mass limits, coupled with our precise determinations of the planetary radii, suggest that their bulk compositions are consistent with a significant amount of water content and the presence of H2 gaseous envelopes. Finally, our photodynamical analysis also shows that the orbits of both planets around Kepler-278 are highly eccentric (e ~ 0.7) and, surprisingly, coplanar. Further observations (e.g., precise radial velocities) of this system are needed to confirm the eccentricity values presented here.
Fil: Jofré, Edgardo. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Departamento de Astrofísica Estelar; Argentina. Universidad Nacional Autónoma de México; México. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina
Fil: Almenara, J.M.. Universidad de Ginebra; Suiza
Fil: Petrucci, Romina Paola. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Departamento de Astrofísica Estelar; Argentina. Universidad Nacional Autónoma de México; México. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina
Fil: Diaz, Rodrigo Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
Fil: Gómez Maqueo Chew, Y.. Universidad Nacional Autónoma de México; México
Fil: Martioli, E.. Laboratorio Nacional de Astrofísica; Brasil
Fil: Ramírez, I.. Tacoma Community College; Estados Unidos
Fil: García, Luciano Héctor. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Departamento de Astrofísica Estelar; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina
Fil: Saffe, Carlos. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; Argentina
Fil: Canul, E. F.. Universidad Nacional Autónoma de México; México
Fil: Buccino, Andrea Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
Fil: Gómez, Marcos Javier. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Departamento de Astrofísica Estelar; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina
Fil: Moreno Hilario, E.. Universidad Nacional Autónoma de México; México
Materia
PLANETARY SYSTEMS
STARS: ABUNDANCES
STARS: FUNDAMENTAL PARAMETERS
STARS: INDIVIDUAL: KEPLER-278
STARS: INDIVIDUAL: KEPLER-391
TECHNIQUES: SPECTROSCOPIC
Nivel de accesibilidad
acceso abierto
Condiciones de uso
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
Repositorio
CONICET Digital (CONICET)
Institución
Consejo Nacional de Investigaciones Científicas y Técnicas
OAI Identificador
oai:ri.conicet.gov.ar:11336/129795

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network_name_str CONICET Digital (CONICET)
spelling Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets: I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391Jofré, EdgardoAlmenara, J.M.Petrucci, Romina PaolaDiaz, Rodrigo FernandoGómez Maqueo Chew, Y.Martioli, E.Ramírez, I.García, Luciano HéctorSaffe, CarlosCanul, E. F.Buccino, Andrea PaolaGómez, Marcos JavierMoreno Hilario, E.PLANETARY SYSTEMSSTARS: ABUNDANCESSTARS: FUNDAMENTAL PARAMETERSSTARS: INDIVIDUAL: KEPLER-278STARS: INDIVIDUAL: KEPLER-391TECHNIQUES: SPECTROSCOPIChttps://purl.org/becyt/ford/1.3https://purl.org/becyt/ford/1Aims. Kepler-278 and Kepler-391 are two of the three evolved stars known to date on the red giant branch (RGB) to host multiple short-period transiting planets. Moreover, the planets orbiting Kepler-278 and Kepler-391 are among the smallest discovered around RGB stars. Here we present a detailed stellar and planetary characterization of these remarkable systems. Methods. Based on high-quality spectra from Gemini-GRACES for Kepler-278 and Kepler-391, we obtained refined stellar parameters and precise chemical abundances for 25 elements. Nine of these elements and the carbon isotopic ratios, 12C∕ 13C, had not previously been measured. Also, combining our new stellar parameters with a photodynamical analysis of the Kepler light curves, we determined accurate planetary properties of both systems. Results. Our revised stellar parameters agree reasonably well with most of the previous results, although we find that Kepler-278 is ~15% less massive than previously reported. The abundances of C, N, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, and Ce, in both stars, are consistent with those of nearby evolved thin disk stars. Kepler-391 presents a relatively high abundance of lithium (A(Li)NLTE = 1.29 ± 0.09 dex), which is likely a remnant from the main-sequence phase. The precise spectroscopic parameters of Kepler-278 and Kepler-391, along with their high 12C∕ 13C ratios, show that both stars are just starting their ascent on the RGB. The planets Kepler-278b, Kepler-278c, and Kepler-391c are warm sub-Neptunes, whilst Kepler-391b is a hot sub-Neptune that falls in the hot super-Earth desert and, therefore, it might be undergoing photoevaporation of its outer envelope. The high-precision obtained in the transit times allowed us not only to confirm Kepler-278c's TTV signal, but also to find evidence of a previously undetected TTV signal for the inner planet Kepler-278b. From the presence of gravitational interaction between these bodies we constrain, for the first time, the mass of Kepler-278b (Mp = 56 -13+37 M⊕ ) and Kepler-278c (Mp = 35 -21+9.9 M⊕ ). The mass limits, coupled with our precise determinations of the planetary radii, suggest that their bulk compositions are consistent with a significant amount of water content and the presence of H2 gaseous envelopes. Finally, our photodynamical analysis also shows that the orbits of both planets around Kepler-278 are highly eccentric (e ~ 0.7) and, surprisingly, coplanar. Further observations (e.g., precise radial velocities) of this system are needed to confirm the eccentricity values presented here.Fil: Jofré, Edgardo. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Departamento de Astrofísica Estelar; Argentina. Universidad Nacional Autónoma de México; México. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Almenara, J.M.. Universidad de Ginebra; SuizaFil: Petrucci, Romina Paola. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Departamento de Astrofísica Estelar; Argentina. Universidad Nacional Autónoma de México; México. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Diaz, Rodrigo Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Gómez Maqueo Chew, Y.. Universidad Nacional Autónoma de México; MéxicoFil: Martioli, E.. Laboratorio Nacional de Astrofísica; BrasilFil: Ramírez, I.. Tacoma Community College; Estados UnidosFil: García, Luciano Héctor. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Departamento de Astrofísica Estelar; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Saffe, Carlos. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; ArgentinaFil: Canul, E. F.. Universidad Nacional Autónoma de México; MéxicoFil: Buccino, Andrea Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; ArgentinaFil: Gómez, Marcos Javier. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Departamento de Astrofísica Estelar; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; ArgentinaFil: Moreno Hilario, E.. Universidad Nacional Autónoma de México; MéxicoEDP Sciences2019-12info:eu-repo/semantics/articleinfo:eu-repo/semantics/publishedVersionhttp://purl.org/coar/resource_type/c_6501info:ar-repo/semantics/articuloapplication/pdfapplication/pdfapplication/pdfhttp://hdl.handle.net/11336/129795Jofré, Edgardo; Almenara, J.M.; Petrucci, Romina Paola; Diaz, Rodrigo Fernando; Gómez Maqueo Chew, Y.; et al.; Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets: I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391; EDP Sciences; Astronomy and Astrophysics; 634; 12-2019; 1-330004-6361CONICET DigitalCONICETenginfo:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201936446info:eu-repo/semantics/altIdentifier/url/https://www.aanda.org/articles/aa/full_html/2020/02/aa36446-19/aa36446-19.htmlinfo:eu-repo/semantics/altIdentifier/url/https://arxiv.org/abs/1912.10278info:eu-repo/semantics/openAccesshttps://creativecommons.org/licenses/by-nc-sa/2.5/ar/reponame:CONICET Digital (CONICET)instname:Consejo Nacional de Investigaciones Científicas y Técnicas2025-09-29T10:45:54Zoai:ri.conicet.gov.ar:11336/129795instacron:CONICETInstitucionalhttp://ri.conicet.gov.ar/Organismo científico-tecnológicoNo correspondehttp://ri.conicet.gov.ar/oai/requestdasensio@conicet.gov.ar; lcarlino@conicet.gov.arArgentinaNo correspondeNo correspondeNo correspondeopendoar:34982025-09-29 10:45:55.035CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicasfalse
dc.title.none.fl_str_mv Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets: I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391
title Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets: I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391
spellingShingle Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets: I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391
Jofré, Edgardo
PLANETARY SYSTEMS
STARS: ABUNDANCES
STARS: FUNDAMENTAL PARAMETERS
STARS: INDIVIDUAL: KEPLER-278
STARS: INDIVIDUAL: KEPLER-391
TECHNIQUES: SPECTROSCOPIC
title_short Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets: I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391
title_full Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets: I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391
title_fullStr Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets: I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391
title_full_unstemmed Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets: I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391
title_sort Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets: I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391
dc.creator.none.fl_str_mv Jofré, Edgardo
Almenara, J.M.
Petrucci, Romina Paola
Diaz, Rodrigo Fernando
Gómez Maqueo Chew, Y.
Martioli, E.
Ramírez, I.
García, Luciano Héctor
Saffe, Carlos
Canul, E. F.
Buccino, Andrea Paola
Gómez, Marcos Javier
Moreno Hilario, E.
author Jofré, Edgardo
author_facet Jofré, Edgardo
Almenara, J.M.
Petrucci, Romina Paola
Diaz, Rodrigo Fernando
Gómez Maqueo Chew, Y.
Martioli, E.
Ramírez, I.
García, Luciano Héctor
Saffe, Carlos
Canul, E. F.
Buccino, Andrea Paola
Gómez, Marcos Javier
Moreno Hilario, E.
author_role author
author2 Almenara, J.M.
Petrucci, Romina Paola
Diaz, Rodrigo Fernando
Gómez Maqueo Chew, Y.
Martioli, E.
Ramírez, I.
García, Luciano Héctor
Saffe, Carlos
Canul, E. F.
Buccino, Andrea Paola
Gómez, Marcos Javier
Moreno Hilario, E.
author2_role author
author
author
author
author
author
author
author
author
author
author
author
dc.subject.none.fl_str_mv PLANETARY SYSTEMS
STARS: ABUNDANCES
STARS: FUNDAMENTAL PARAMETERS
STARS: INDIVIDUAL: KEPLER-278
STARS: INDIVIDUAL: KEPLER-391
TECHNIQUES: SPECTROSCOPIC
topic PLANETARY SYSTEMS
STARS: ABUNDANCES
STARS: FUNDAMENTAL PARAMETERS
STARS: INDIVIDUAL: KEPLER-278
STARS: INDIVIDUAL: KEPLER-391
TECHNIQUES: SPECTROSCOPIC
purl_subject.fl_str_mv https://purl.org/becyt/ford/1.3
https://purl.org/becyt/ford/1
dc.description.none.fl_txt_mv Aims. Kepler-278 and Kepler-391 are two of the three evolved stars known to date on the red giant branch (RGB) to host multiple short-period transiting planets. Moreover, the planets orbiting Kepler-278 and Kepler-391 are among the smallest discovered around RGB stars. Here we present a detailed stellar and planetary characterization of these remarkable systems. Methods. Based on high-quality spectra from Gemini-GRACES for Kepler-278 and Kepler-391, we obtained refined stellar parameters and precise chemical abundances for 25 elements. Nine of these elements and the carbon isotopic ratios, 12C∕ 13C, had not previously been measured. Also, combining our new stellar parameters with a photodynamical analysis of the Kepler light curves, we determined accurate planetary properties of both systems. Results. Our revised stellar parameters agree reasonably well with most of the previous results, although we find that Kepler-278 is ~15% less massive than previously reported. The abundances of C, N, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, and Ce, in both stars, are consistent with those of nearby evolved thin disk stars. Kepler-391 presents a relatively high abundance of lithium (A(Li)NLTE = 1.29 ± 0.09 dex), which is likely a remnant from the main-sequence phase. The precise spectroscopic parameters of Kepler-278 and Kepler-391, along with their high 12C∕ 13C ratios, show that both stars are just starting their ascent on the RGB. The planets Kepler-278b, Kepler-278c, and Kepler-391c are warm sub-Neptunes, whilst Kepler-391b is a hot sub-Neptune that falls in the hot super-Earth desert and, therefore, it might be undergoing photoevaporation of its outer envelope. The high-precision obtained in the transit times allowed us not only to confirm Kepler-278c's TTV signal, but also to find evidence of a previously undetected TTV signal for the inner planet Kepler-278b. From the presence of gravitational interaction between these bodies we constrain, for the first time, the mass of Kepler-278b (Mp = 56 -13+37 M⊕ ) and Kepler-278c (Mp = 35 -21+9.9 M⊕ ). The mass limits, coupled with our precise determinations of the planetary radii, suggest that their bulk compositions are consistent with a significant amount of water content and the presence of H2 gaseous envelopes. Finally, our photodynamical analysis also shows that the orbits of both planets around Kepler-278 are highly eccentric (e ~ 0.7) and, surprisingly, coplanar. Further observations (e.g., precise radial velocities) of this system are needed to confirm the eccentricity values presented here.
Fil: Jofré, Edgardo. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Departamento de Astrofísica Estelar; Argentina. Universidad Nacional Autónoma de México; México. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina
Fil: Almenara, J.M.. Universidad de Ginebra; Suiza
Fil: Petrucci, Romina Paola. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Departamento de Astrofísica Estelar; Argentina. Universidad Nacional Autónoma de México; México. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina
Fil: Diaz, Rodrigo Fernando. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
Fil: Gómez Maqueo Chew, Y.. Universidad Nacional Autónoma de México; México
Fil: Martioli, E.. Laboratorio Nacional de Astrofísica; Brasil
Fil: Ramírez, I.. Tacoma Community College; Estados Unidos
Fil: García, Luciano Héctor. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Departamento de Astrofísica Estelar; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina
Fil: Saffe, Carlos. Universidad Nacional de San Juan. Facultad de Ciencias Exactas, Físicas y Naturales; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio. Universidad Nacional de San Juan. Instituto de Ciencias Astronómicas, de la Tierra y del Espacio; Argentina
Fil: Canul, E. F.. Universidad Nacional Autónoma de México; México
Fil: Buccino, Andrea Paola. Consejo Nacional de Investigaciones Científicas y Técnicas. Oficina de Coordinación Administrativa Ciudad Universitaria. Instituto de Astronomía y Física del Espacio. - Universidad de Buenos Aires. Facultad de Ciencias Exactas y Naturales. Instituto de Astronomía y Física del Espacio; Argentina
Fil: Gómez, Marcos Javier. Universidad Nacional de Córdoba. Observatorio Astronómico de Córdoba. Departamento de Astrofísica Estelar; Argentina. Consejo Nacional de Investigaciones Científicas y Técnicas. Centro Científico Tecnológico Conicet - Córdoba; Argentina
Fil: Moreno Hilario, E.. Universidad Nacional Autónoma de México; México
description Aims. Kepler-278 and Kepler-391 are two of the three evolved stars known to date on the red giant branch (RGB) to host multiple short-period transiting planets. Moreover, the planets orbiting Kepler-278 and Kepler-391 are among the smallest discovered around RGB stars. Here we present a detailed stellar and planetary characterization of these remarkable systems. Methods. Based on high-quality spectra from Gemini-GRACES for Kepler-278 and Kepler-391, we obtained refined stellar parameters and precise chemical abundances for 25 elements. Nine of these elements and the carbon isotopic ratios, 12C∕ 13C, had not previously been measured. Also, combining our new stellar parameters with a photodynamical analysis of the Kepler light curves, we determined accurate planetary properties of both systems. Results. Our revised stellar parameters agree reasonably well with most of the previous results, although we find that Kepler-278 is ~15% less massive than previously reported. The abundances of C, N, O, Na, Mg, Al, Si, S, Ca, Sc, Ti, V, Cr, Mn, Co, Ni, Cu, Zn, Sr, Y, Zr, Ba, and Ce, in both stars, are consistent with those of nearby evolved thin disk stars. Kepler-391 presents a relatively high abundance of lithium (A(Li)NLTE = 1.29 ± 0.09 dex), which is likely a remnant from the main-sequence phase. The precise spectroscopic parameters of Kepler-278 and Kepler-391, along with their high 12C∕ 13C ratios, show that both stars are just starting their ascent on the RGB. The planets Kepler-278b, Kepler-278c, and Kepler-391c are warm sub-Neptunes, whilst Kepler-391b is a hot sub-Neptune that falls in the hot super-Earth desert and, therefore, it might be undergoing photoevaporation of its outer envelope. The high-precision obtained in the transit times allowed us not only to confirm Kepler-278c's TTV signal, but also to find evidence of a previously undetected TTV signal for the inner planet Kepler-278b. From the presence of gravitational interaction between these bodies we constrain, for the first time, the mass of Kepler-278b (Mp = 56 -13+37 M⊕ ) and Kepler-278c (Mp = 35 -21+9.9 M⊕ ). The mass limits, coupled with our precise determinations of the planetary radii, suggest that their bulk compositions are consistent with a significant amount of water content and the presence of H2 gaseous envelopes. Finally, our photodynamical analysis also shows that the orbits of both planets around Kepler-278 are highly eccentric (e ~ 0.7) and, surprisingly, coplanar. Further observations (e.g., precise radial velocities) of this system are needed to confirm the eccentricity values presented here.
publishDate 2019
dc.date.none.fl_str_mv 2019-12
dc.type.none.fl_str_mv info:eu-repo/semantics/article
info:eu-repo/semantics/publishedVersion
http://purl.org/coar/resource_type/c_6501
info:ar-repo/semantics/articulo
format article
status_str publishedVersion
dc.identifier.none.fl_str_mv http://hdl.handle.net/11336/129795
Jofré, Edgardo; Almenara, J.M.; Petrucci, Romina Paola; Diaz, Rodrigo Fernando; Gómez Maqueo Chew, Y.; et al.; Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets: I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391; EDP Sciences; Astronomy and Astrophysics; 634; 12-2019; 1-33
0004-6361
CONICET Digital
CONICET
url http://hdl.handle.net/11336/129795
identifier_str_mv Jofré, Edgardo; Almenara, J.M.; Petrucci, Romina Paola; Diaz, Rodrigo Fernando; Gómez Maqueo Chew, Y.; et al.; Gemini-GRACES high-quality spectra of Kepler evolved stars with transiting planets: I. Detailed characterization of multi-planet systems Kepler-278 and Kepler-391; EDP Sciences; Astronomy and Astrophysics; 634; 12-2019; 1-33
0004-6361
CONICET Digital
CONICET
dc.language.none.fl_str_mv eng
language eng
dc.relation.none.fl_str_mv info:eu-repo/semantics/altIdentifier/doi/10.1051/0004-6361/201936446
info:eu-repo/semantics/altIdentifier/url/https://www.aanda.org/articles/aa/full_html/2020/02/aa36446-19/aa36446-19.html
info:eu-repo/semantics/altIdentifier/url/https://arxiv.org/abs/1912.10278
dc.rights.none.fl_str_mv info:eu-repo/semantics/openAccess
https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
eu_rights_str_mv openAccess
rights_invalid_str_mv https://creativecommons.org/licenses/by-nc-sa/2.5/ar/
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application/pdf
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dc.publisher.none.fl_str_mv EDP Sciences
publisher.none.fl_str_mv EDP Sciences
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reponame_str CONICET Digital (CONICET)
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instname_str Consejo Nacional de Investigaciones Científicas y Técnicas
repository.name.fl_str_mv CONICET Digital (CONICET) - Consejo Nacional de Investigaciones Científicas y Técnicas
repository.mail.fl_str_mv dasensio@conicet.gov.ar; lcarlino@conicet.gov.ar
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