K2-280 b – a low density warm sub-Saturn around a mildly evolved star-Reference-Cited by-同舟云学术

K2-280 b – a low density warm sub-Saturn around a mildly evolved star

Published:2020-07-17 Issue:4 Volume:497 Page:4423-4435
ISSN:0035-8711
Container-title:Monthly Notices of the Royal Astronomical Society
language:en
Short-container-title:

Author:

Nowak Grzegorz¹²,Palle Enric¹²,Gandolfi Davide³,Deeg Hans J¹²,Hirano Teruyuki⁴,Barragán Oscar⁵³,Kuzuhara Masayuki⁶⁷,Dai Fei⁸⁹,Luque Rafael¹²^ORCID,Persson Carina M¹⁰,Fridlund Malcolm¹⁰¹¹^ORCID,Johnson Marshall C¹²^ORCID,Korth Judith¹³,Livingston John H¹⁴^ORCID,Grziwa Sascha¹³,Mathur Savita¹²,Hatzes Artie P¹⁵,Prieto-Arranz Jorge¹²,Nespral David¹²,Hidalgo Diego¹²,Hjorth Maria¹⁶,Albrecht Simon¹⁶,Van Eylen Vincent⁸,Lam Kristine W F¹⁷,Cochran William D¹⁸¹⁹,Esposito Massimiliano¹⁵,Csizmadia Szilárd²⁰^ORCID,Guenther Eike W¹⁵,Kabath Petr²¹,Blay Pere²²,Brahm Rafael²³²⁴,Jordán Andrés²³²⁴,Espinoza Néstor²⁵^ORCID,Rojas Felipe²⁶²⁴,Casasayas Barris Núria¹²,Rodler Florian²⁷,Alonso Sobrino Roi¹²,Cabrera Juan²⁰,Carleo Ilaria²⁸,Chaushev Alexander¹⁷,de Leon Jerome¹⁴,Eigmüller Philipp²⁰,Endl Michael¹⁹,Erikson Anders²⁰,Fukui Akihiko⁷,Georgieva Iskra¹⁰,González-Cuesta Lucía¹²,Knudstrup Emil¹⁶^ORCID,Lund Mikkel N¹⁶^ORCID,Montañes Rodríguez Pilar¹²,Murgas Felipe¹²,Narita Norio¹⁶⁷²⁹,Niraula Prajwal³⁰,Pätzold Martin¹³,Rauer Heike²⁰¹⁷,Redfield Seth²⁸^ORCID,Ribas Ignasi³¹³²,Skarka Marek²¹³³^ORCID,Smith Alexis M S²⁰,Subjak Jano²¹³⁴

Affiliation:

1. Instituto de Astrofísica de Canarias (IAC), E-38205 La Laguna, Tenerife, Spain

2. Departamento de Astrofísica, Universidad de La Laguna (ULL), E-38206 La Laguna, Tenerife, Spain

3. Dipartimento di Fisica, Universitá di Torino, Via P. Giuria 1, I-10125, Torino, Italy

4. Department of Earth and Planetary Sciences, Tokyo Institute of Technology, 2-12-1 Ookayama, Meguro-ku, Tokyo, Japan

5. Sub-department of Astrophysics, Department of Physics, University of Oxford, Oxford OX1 3RH, UK

6. Astrobiology Center, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan

7. National Astronomical Observatory of Japan, NINS, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan

8. Department of Astrophysical Sciences, Princeton University, 4 Ivy Lane, Princeton, NJ 08544, USA

9. Department of Physics and Kavli Institute for Astrophysics and Space Research, MIT, Cambridge, MA 02139, USA

10. Chalmers University of Technology, Department of Space, Earth and Environment, Onsala Space Observatory, SE-439 92 Onsala, Sweden

11. Leiden Observatory, University of Leiden, PO Box 9513, NL-2300 RA, Leiden, The Netherlands

12. Las Cumbres Observatory, 6740 Cortona Dr., Ste. 102, Goleta, CA 93117, USA

13. Rheinisches Institut für Umweltforschung an der Universität zu Köln, Aachener Strasse 209, D-50931 Köln, Germany

14. Department of Astronomy, The University of Tokyo, 7-3-1 Hongo, Bunkyo-ku, Tokyo 113-0033, Japan

15. Thüringer Landessternwarte Tautenburg, D-07778 Tautenburg, Germany

16. Stellar Astrophysics Centre, Department of Physics and Astronomy, Aarhus University, Ny Munkegade 120, DK-8000 Aarhus C, Denmark

17. Center for Astronomy and Astrophysics, TU Berlin, Hardenbergstr. 36, D-10623 Berlin, Germany

18. Department of Astronomy and McDonald Observatory, University of Texas at Austin, 2515 Speedway, Austin, TX 78712, USA

19. Center for Planetary Systems Habitability, University of Texas at Austin, Austin, TX 78730, USA

20. Institute of Planetary Research, German Aerospace Center (DLR), Rutherfordstrasse 2, D-12489 Berlin, Germany

21. Astronomical Institute, Czech Academy of Sciences, Fričova 298, CZ-25165 Ondřejov, Czech Republic

22. Valencian International University (VIU), Pintor Sorolla 21, E-46002 Valencia, Spain

23. Facultad de Ingeniería y Ciencias, Universidad Adolfo Ibánez, Av. Diagonal las Torres 2640, Peñalolén, Santiago, Chile

24. Millennium Institute for Astrophysics, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago, Chile

25. Max-Planck-Institut für Astronomie, Königstuhl 17, D-69117 Heidelberg, Germany

26. Instituto de Astrofísica, Pontificia Universidad Católica de Chile, Av. Vicuña Mackenna 4860, 782-0436 Macul, Santiago, Chile

27. European Southern Observatory, Alonso de Córdova 3107, Vitacura, Casilla 19001, Santiago de Chile, Chile

28. Astronomy Department and Van Vleck Observatory, Wesleyan University, Middletown, CT 06459, USA

29. JST, PRESTO, 2-21-1 Osawa, Mitaka, Tokyo 181-8588, Japan

30. Department of Earth, Atmospheric and Planetary Sciences, MIT, 77 Massachusetts Avenue, Cambridge, MA 02139, USA

31. Institut de Ciències de l’Espai (ICE, CSIC), Campus UAB,C/ de Can Magrans s/n, E-08193 Bellaterra, Spain

32. Institut d’Estudis Espacials de Catalunya (IEEC), C/ Gran Capitá 2-4, E-08034 Barcelona, Spain

33. Department of Theoretical Physics and Astrophysics, Masaryk University, Kotlářská 2, CZ-61137 Brno, Czech Republic

34. Astronomical Institute, Faculty of Mathematics and Physics, Charles University, Ke Karlovu 2027/3, CZ-12116 Prague, Czech Republic

Abstract

ABSTRACT We present an independent discovery and detailed characterization of K2-280 b, a transiting low density warm sub-Saturn in a 19.9-d moderately eccentric orbit (e = $0.35_{-0.04}^{+0.05}$ ) from K2 campaign 7. A joint analysis of high precision HARPS, HARPS-N, and FIES radial velocity measurements and K2 photometric data indicates that K2-280 b has a radius of Rb = 7.50 ± 0.44 R⊕ and a mass of Mb = 37.1 ± 5.6 M⊕, yielding a mean density of ρb = $0.48 _{ - 0.10 } ^ { + 0.13 }$ ${\rm g\, cm^{-3}}$. The host star is a mildly evolved G7 star with an effective temperature of Teff = 5500 ± 100 K, a surface gravity of $\log \, g_{\star }$ = 4.21 ± 0.05 (cgs), and an iron abundance of [Fe/H] = ${0.33}\, {\pm }\, {0.08}$ dex, and with an inferred mass of M⋆ = 1.03 ± 0.03 M⊙ and a radius of R⋆ = 1.28 ± 0.07 R⊙. We discuss the importance of K2-280 b for testing formation scenarios of sub-Saturn planets and the current sample of this intriguing group of planets that are absent in the Solar system.

Funder

Ministerio de Economía y Competitividad

Science and Technology Facilities Council

Swedish National Space Agency

Deutsche Forschungsgemeinschaft

Japan Society for the Promotion of Science

Japan Science and Technology Corporation

Fondo Nacional de Desarrollo Científico y Tecnológico

Ministerio de Economía, Fomento y Turismo

National Science Foundation

National Research Council Canada

Comisión Nacional de Investigación Científica y Tecnológica