KEPLER-21b: A ROCKY PLANET AROUND A v = 8.25 mag STAR

Mercedes López-Morales; Raphaëlle D. Haywood; Jeffrey L. Coughlin; Li Zeng; Lars A. Buchhave; Helen A.C. Giles; Laura Affer; Aldo S. Bonomo; David Charbonneau; Andrew Collier Cameron; Rosario Consentino; Courtney D. Dressing; Xavier Dumusque; Pedro Figueira; Aldo F.M. Fiorenzano; Avet Harutyunyan; John Asher Johnson; David W. Latham; Eric D. Lopez; Christophe Lovis; Luca Malavolta; Michel Mayor; Giusi Micela; Emilio Molinari; Annelies Mortier; Fatemeh Motalebi; Valerio Nascimbeni; Francesco Pepe; David F. Phillips; Giampaolo Piotto; Don Pollacco; Didier Queloz; Ken Rice; Dimitar Sasselov; Damien Segransan; Alessandro Sozzetti; Stephane Udry; Andrew Vanderburg; Chris Watson

doi:10.3847/0004-6256/152/6/204

KEPLER-21b: A ROCKY PLANET AROUND A v = 8.25 mag STAR

Mercedes López-Morales, Raphaëlle D. Haywood, Jeffrey L. Coughlin, Li Zeng, Lars A. Buchhave, Helen A.C. Giles, Laura Affer, Aldo S. Bonomo, David Charbonneau, Andrew Collier Cameron, Rosario Consentino, Courtney D. Dressing, Xavier Dumusque, Pedro Figueira, Aldo F.M. Fiorenzano, Avet Harutyunyan, John Asher Johnson, David W. Latham, Eric D. Lopez, Christophe LovisLuca Malavolta, Michel Mayor, Giusi Micela, Emilio Molinari, Annelies Mortier, Fatemeh Motalebi, Valerio Nascimbeni, Francesco Pepe, David F. Phillips, Giampaolo Piotto, Don Pollacco, Didier Queloz, Ken Rice, Dimitar Sasselov, Damien Segransan, Alessandro Sozzetti, Stephane Udry, Andrew Vanderburg, Chris Watson

Physics and Astronomy

Research output: Contribution to journal › Article › peer-review

75 Citations (Scopus)

Abstract

HD 179070, aka Kepler-21, is a V = 8.25 F6IV star and the brightest exoplanet host discovered by Kepler. An early detailed analysis by Howell et al. of the first 13 months (Q0-Q5) of Kepler light curves revealed transits of a planetary companion, Kepler-21b, with a radius of about 1.60 ± 0.04 and an orbital period of about 2.7857 days. However, they could not determine the mass of the planet from the initial radial velocity (RV) observations with Keck-HIRES, and were only able to impose a 2σ upper limit of 10 . Here, we present results from the analysis of 82 new RV observations of this system obtained with HARPS-N, together with the existing 14 HIRES data points. We detect the Doppler signal of Kepler-21b with a RV semiamplitude K = 2.00 ± 0.65m^s-1, which corresponds to a planetary mass of 5.1 ± 1.7 M⊕ We also measure an improved radius for the planet of 1.639 +0.019/-0.015 R⊕, in agreement with the radius reported by Howell et al. We conclude that Kepler-21b, with a density of 6.4 ± 2.1 g ^cm-1, belongs to the population of small, ≲6 planets with iron and magnesium silicate interiors, which have lost the majority of their envelope volatiles via stellar winds or gravitational escape. The RV analysis presented in this paper serves as an example of the type of analysis that will be necessary to confirm the masses of TESS small planet candidates.

Original language	English
Article number	204
Journal	Astronomical Journal
Volume	152
Issue number	6
DOIs	https://doi.org/10.3847/0004-6256/152/6/204
Publication status	Published - Dec 2016

Bibliographical note

Publisher Copyright:
© 2016. The American Astronomical Society. All rights reserved..

Keywords

planets and satellites: formation
planets and satellites: individual (Kepler-21b)
stars: individual (HD 179070)
techniques: photometric
techniques: radial velocities
techniques: spectroscopic

ASJC Scopus subject areas

Astronomy and Astrophysics
Space and Planetary Science

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10.3847/0004-6256/152/6/204

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López-Morales, M., Haywood, R. D., Coughlin, J. L., Zeng, L., Buchhave, L. A., Giles, H. A. C., Affer, L., Bonomo, A. S., Charbonneau, D., Cameron, A. C., Consentino, R., Dressing, C. D., Dumusque, X., Figueira, P., Fiorenzano, A. F. M., Harutyunyan, A., Johnson, J. A., Latham, D. W., Lopez, E. D., ... Watson, C. (2016). KEPLER-21b: A ROCKY PLANET AROUND A v = 8.25 mag STAR. Astronomical Journal, 152(6), Article 204. https://doi.org/10.3847/0004-6256/152/6/204

@article{d04f41a7ce804f12a72829265da517e9,

title = "KEPLER-21b: A ROCKY PLANET AROUND A v = 8.25 mag STAR",

abstract = "HD 179070, aka Kepler-21, is a V = 8.25 F6IV star and the brightest exoplanet host discovered by Kepler. An early detailed analysis by Howell et al. of the first 13 months (Q0-Q5) of Kepler light curves revealed transits of a planetary companion, Kepler-21b, with a radius of about 1.60 ± 0.04 and an orbital period of about 2.7857 days. However, they could not determine the mass of the planet from the initial radial velocity (RV) observations with Keck-HIRES, and were only able to impose a 2σ upper limit of 10 . Here, we present results from the analysis of 82 new RV observations of this system obtained with HARPS-N, together with the existing 14 HIRES data points. We detect the Doppler signal of Kepler-21b with a RV semiamplitude K = 2.00 ± 0.65ms-1, which corresponds to a planetary mass of 5.1 ± 1.7 M⊕ We also measure an improved radius for the planet of 1.639 +0.019/-0.015 R⊕, in agreement with the radius reported by Howell et al. We conclude that Kepler-21b, with a density of 6.4 ± 2.1 g cm-1, belongs to the population of small, ≲6 planets with iron and magnesium silicate interiors, which have lost the majority of their envelope volatiles via stellar winds or gravitational escape. The RV analysis presented in this paper serves as an example of the type of analysis that will be necessary to confirm the masses of TESS small planet candidates.",

keywords = "planets and satellites: formation, planets and satellites: individual (Kepler-21b), stars: individual (HD 179070), techniques: photometric, techniques: radial velocities, techniques: spectroscopic",

author = "Mercedes L{\'o}pez-Morales and Haywood, {Rapha{\"e}lle D.} and Coughlin, {Jeffrey L.} and Li Zeng and Buchhave, {Lars A.} and Giles, {Helen A.C.} and Laura Affer and Bonomo, {Aldo S.} and David Charbonneau and Cameron, {Andrew Collier} and Rosario Consentino and Dressing, {Courtney D.} and Xavier Dumusque and Pedro Figueira and Fiorenzano, {Aldo F.M.} and Avet Harutyunyan and Johnson, {John Asher} and Latham, {David W.} and Lopez, {Eric D.} and Christophe Lovis and Luca Malavolta and Michel Mayor and Giusi Micela and Emilio Molinari and Annelies Mortier and Fatemeh Motalebi and Valerio Nascimbeni and Francesco Pepe and Phillips, {David F.} and Giampaolo Piotto and Don Pollacco and Didier Queloz and Ken Rice and Dimitar Sasselov and Damien Segransan and Alessandro Sozzetti and Stephane Udry and Andrew Vanderburg and Chris Watson",

year = "2016",

month = dec,

doi = "10.3847/0004-6256/152/6/204",

language = "English",

volume = "152",

journal = "Astronomical Journal",

issn = "0004-6256",

publisher = "American Astronomical Society",

number = "6",

}

López-Morales, M, Haywood, RD, Coughlin, JL, Zeng, L, Buchhave, LA, Giles, HAC, Affer, L, Bonomo, AS, Charbonneau, D, Cameron, AC, Consentino, R, Dressing, CD, Dumusque, X, Figueira, P, Fiorenzano, AFM, Harutyunyan, A, Johnson, JA, Latham, DW, Lopez, ED, Lovis, C, Malavolta, L, Mayor, M, Micela, G, Molinari, E, Mortier, A, Motalebi, F, Nascimbeni, V, Pepe, F, Phillips, DF, Piotto, G, Pollacco, D, Queloz, D, Rice, K, Sasselov, D, Segransan, D, Sozzetti, A, Udry, S, Vanderburg, A & Watson, C 2016, 'KEPLER-21b: A ROCKY PLANET AROUND A v = 8.25 mag STAR', Astronomical Journal, vol. 152, no. 6, 204. https://doi.org/10.3847/0004-6256/152/6/204

TY - JOUR

T1 - KEPLER-21b

T2 - A ROCKY PLANET AROUND A v = 8.25 mag STAR

AU - López-Morales, Mercedes

AU - Haywood, Raphaëlle D.

AU - Coughlin, Jeffrey L.

AU - Zeng, Li

AU - Buchhave, Lars A.

AU - Giles, Helen A.C.

AU - Affer, Laura

AU - Bonomo, Aldo S.

AU - Charbonneau, David

AU - Cameron, Andrew Collier

AU - Consentino, Rosario

AU - Dressing, Courtney D.

AU - Dumusque, Xavier

AU - Figueira, Pedro

AU - Fiorenzano, Aldo F.M.

AU - Harutyunyan, Avet

AU - Johnson, John Asher

AU - Latham, David W.

AU - Lopez, Eric D.

AU - Lovis, Christophe

AU - Malavolta, Luca

AU - Mayor, Michel

AU - Micela, Giusi

AU - Molinari, Emilio

AU - Mortier, Annelies

AU - Motalebi, Fatemeh

AU - Nascimbeni, Valerio

AU - Pepe, Francesco

AU - Phillips, David F.

AU - Piotto, Giampaolo

AU - Pollacco, Don

AU - Queloz, Didier

AU - Rice, Ken

AU - Sasselov, Dimitar

AU - Segransan, Damien

AU - Sozzetti, Alessandro

AU - Udry, Stephane

AU - Vanderburg, Andrew

AU - Watson, Chris

PY - 2016/12

Y1 - 2016/12

N2 - HD 179070, aka Kepler-21, is a V = 8.25 F6IV star and the brightest exoplanet host discovered by Kepler. An early detailed analysis by Howell et al. of the first 13 months (Q0-Q5) of Kepler light curves revealed transits of a planetary companion, Kepler-21b, with a radius of about 1.60 ± 0.04 and an orbital period of about 2.7857 days. However, they could not determine the mass of the planet from the initial radial velocity (RV) observations with Keck-HIRES, and were only able to impose a 2σ upper limit of 10 . Here, we present results from the analysis of 82 new RV observations of this system obtained with HARPS-N, together with the existing 14 HIRES data points. We detect the Doppler signal of Kepler-21b with a RV semiamplitude K = 2.00 ± 0.65ms-1, which corresponds to a planetary mass of 5.1 ± 1.7 M⊕ We also measure an improved radius for the planet of 1.639 +0.019/-0.015 R⊕, in agreement with the radius reported by Howell et al. We conclude that Kepler-21b, with a density of 6.4 ± 2.1 g cm-1, belongs to the population of small, ≲6 planets with iron and magnesium silicate interiors, which have lost the majority of their envelope volatiles via stellar winds or gravitational escape. The RV analysis presented in this paper serves as an example of the type of analysis that will be necessary to confirm the masses of TESS small planet candidates.

AB - HD 179070, aka Kepler-21, is a V = 8.25 F6IV star and the brightest exoplanet host discovered by Kepler. An early detailed analysis by Howell et al. of the first 13 months (Q0-Q5) of Kepler light curves revealed transits of a planetary companion, Kepler-21b, with a radius of about 1.60 ± 0.04 and an orbital period of about 2.7857 days. However, they could not determine the mass of the planet from the initial radial velocity (RV) observations with Keck-HIRES, and were only able to impose a 2σ upper limit of 10 . Here, we present results from the analysis of 82 new RV observations of this system obtained with HARPS-N, together with the existing 14 HIRES data points. We detect the Doppler signal of Kepler-21b with a RV semiamplitude K = 2.00 ± 0.65ms-1, which corresponds to a planetary mass of 5.1 ± 1.7 M⊕ We also measure an improved radius for the planet of 1.639 +0.019/-0.015 R⊕, in agreement with the radius reported by Howell et al. We conclude that Kepler-21b, with a density of 6.4 ± 2.1 g cm-1, belongs to the population of small, ≲6 planets with iron and magnesium silicate interiors, which have lost the majority of their envelope volatiles via stellar winds or gravitational escape. The RV analysis presented in this paper serves as an example of the type of analysis that will be necessary to confirm the masses of TESS small planet candidates.

KW - planets and satellites: formation

KW - planets and satellites: individual (Kepler-21b)

KW - stars: individual (HD 179070)

KW - techniques: photometric

KW - techniques: radial velocities

KW - techniques: spectroscopic

UR - http://www.scopus.com/inward/record.url?scp=85009101111&partnerID=8YFLogxK

U2 - 10.3847/0004-6256/152/6/204

DO - 10.3847/0004-6256/152/6/204

M3 - Article

AN - SCOPUS:85009101111

SN - 0004-6256

VL - 152

JO - Astronomical Journal

JF - Astronomical Journal

IS - 6

M1 - 204

ER -

KEPLER-21b: A ROCKY PLANET AROUND A v = 8.25 mag STAR

Abstract

Bibliographical note

Keywords

ASJC Scopus subject areas

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