HD 89345: A bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2

V. Van Eylen; F. Dai; S. Mathur; D. Gandolfi; S. Albrecht; M. Fridlund; R. A. García; E. Guenther; M. Hjorth; A. B. Justesen; J. Livingston; M. N. Lund; F. Pérez Hernández; J. Prieto-Arranz; C. Regulo; L. Bugnet; M. E. Everett; T. Hirano; D. Nespral; G. Nowak; E. Palle; V. Silva Aguirre; T. Trifonov; J. N. Winn; O. Barragán; P. G. Beck; W. J. Chaplin; W. D. Cochran; S. Csizmadia; H. Deeg; M. Endl; P. Heeren; S. Grziwa; A. P. Hatzes; D. Hidalgo; J. Korth; S. Mathis; P. Montañes Rodriguez; N. Narita; M. Patzold; C. M. Persson; F. Rodler; A. M.S. Smith

doi:10.1093/mnras/sty1390

HD 89345: A bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2

V. Van Eylen, F. Dai, S. Mathur, D. Gandolfi, S. Albrecht, M. Fridlund, R. A. García, E. Guenther, M. Hjorth, A. B. Justesen, J. Livingston, M. N. Lund, F. Pérez Hernández, J. Prieto-Arranz, C. Regulo, L. Bugnet, M. E. Everett, T. Hirano, D. Nespral, G. NowakE. Palle, V. Silva Aguirre, T. Trifonov, J. N. Winn, O. Barragán, P. G. Beck, W. J. Chaplin, W. D. Cochran, S. Csizmadia, H. Deeg, M. Endl, P. Heeren, S. Grziwa, A. P. Hatzes, D. Hidalgo, J. Korth, S. Mathis, P. Montañes Rodriguez, N. Narita, M. Patzold, C. M. Persson, F. Rodler, A. M.S. Smith

Astrophysical Sciences

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Abstract

We report the discovery and characterization of HD 89345b (K2-234b; EPIC 248777106b), a Saturn-sized planet orbiting a slightly evolved star. HD 89345 is a bright star (V = 9.3 mag) observed by the K2 mission with 1 min time sampling. It exhibits solar-like oscillations. We conducted asteroseismology to determine the parameters of the star, finding themass and radius to be 1.12-_0.01^+0.04 M_⊙ and 1.657 _-0.004 ^+0.020 R_⊙, respectively. The star appears to have recently left the main sequence, based on the inferred age, 9.4_-1.3^+0.4 Gyr, and the non-detection of mixed modes. The star hosts a 'warm Saturn' (P = 11.8 d, R_p = 6.86 ± 0.14 R_⊕). Radial-velocity follow-up observations performed with the FIbre-fed Echelle Spectrograph, HARPS, and HARPS-N spectrographs show that the planet has a mass of 35.7 ± 3.3 M_⊕. The data also show that the planet's orbit is eccentric (e≈0.2). An investigation of the rotational splitting of the oscillation frequencies of the star yields no conclusive evidence on the stellar inclination angle. We further obtained Rossiter-McLaughlin observations, which result in a broad posterior of the stellar obliquity. The planet seems to confirm to the same patterns that have been observed for other sub-Saturns regarding planet mass and multiplicity, orbital eccentricity, and stellar metallicity.

Original language	English (US)
Pages (from-to)	4866-4880
Number of pages	15
Journal	Monthly Notices of the Royal Astronomical Society
Volume	478
Issue number	4
DOIs	https://doi.org/10.1093/mnras/sty1390
State	Published - Aug 21 2018

All Science Journal Classification (ASJC) codes

Astronomy and Astrophysics
Space and Planetary Science

Keywords

Asteroseismology
Planets and satellites: composition
Planets and satellites: formation
Planets and satellites: fundamental parameters

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10.1093/mnras/sty1390

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Van Eylen, V., Dai, F., Mathur, S., Gandolfi, D., Albrecht, S., Fridlund, M., García, R. A., Guenther, E., Hjorth, M., Justesen, A. B., Livingston, J., Lund, M. N., Pérez Hernández, F., Prieto-Arranz, J., Regulo, C., Bugnet, L., Everett, M. E., Hirano, T., Nespral, D., ... Smith, A. M. S. (2018). HD 89345: A bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2. Monthly Notices of the Royal Astronomical Society, 478(4), 4866-4880. https://doi.org/10.1093/mnras/sty1390

@article{8e94b8eccebc40dc913c4f4ed6dd8fba,

title = "HD 89345: A bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2",

abstract = "We report the discovery and characterization of HD 89345b (K2-234b; EPIC 248777106b), a Saturn-sized planet orbiting a slightly evolved star. HD 89345 is a bright star (V = 9.3 mag) observed by the K2 mission with 1 min time sampling. It exhibits solar-like oscillations. We conducted asteroseismology to determine the parameters of the star, finding themass and radius to be 1.12-0.01+0.04 M⊙ and 1.657 -0.004 +0.020 R⊙, respectively. The star appears to have recently left the main sequence, based on the inferred age, 9.4-1.3+0.4 Gyr, and the non-detection of mixed modes. The star hosts a 'warm Saturn' (P = 11.8 d, Rp = 6.86 ± 0.14 R⊕). Radial-velocity follow-up observations performed with the FIbre-fed Echelle Spectrograph, HARPS, and HARPS-N spectrographs show that the planet has a mass of 35.7 ± 3.3 M⊕. The data also show that the planet's orbit is eccentric (e≈0.2). An investigation of the rotational splitting of the oscillation frequencies of the star yields no conclusive evidence on the stellar inclination angle. We further obtained Rossiter-McLaughlin observations, which result in a broad posterior of the stellar obliquity. The planet seems to confirm to the same patterns that have been observed for other sub-Saturns regarding planet mass and multiplicity, orbital eccentricity, and stellar metallicity.",

keywords = "Asteroseismology, Planets and satellites: composition, Planets and satellites: formation, Planets and satellites: fundamental parameters",

author = "{Van Eylen}, V. and F. Dai and S. Mathur and D. Gandolfi and S. Albrecht and M. Fridlund and Garc{\'i}a, {R. A.} and E. Guenther and M. Hjorth and Justesen, {A. B.} and J. Livingston and Lund, {M. N.} and {P{\'e}rez Hern{\'a}ndez}, F. and J. Prieto-Arranz and C. Regulo and L. Bugnet and Everett, {M. E.} and T. Hirano and D. Nespral and G. Nowak and E. Palle and {Silva Aguirre}, V. and T. Trifonov and Winn, {J. N.} and O. Barrag{\'a}n and Beck, {P. G.} and Chaplin, {W. J.} and Cochran, {W. D.} and S. Csizmadia and H. Deeg and M. Endl and P. Heeren and S. Grziwa and Hatzes, {A. P.} and D. Hidalgo and J. Korth and S. Mathis and Rodriguez, {P. Monta{\~n}es} and N. Narita and M. Patzold and Persson, {C. M.} and F. Rodler and Smith, {A. M.S.}",

note = "Publisher Copyright: {\textcopyright} 2018 The Author(s) Published by Oxford University Press on behalf of the Royal Astronomical Society.",

year = "2018",

month = aug,

day = "21",

doi = "10.1093/mnras/sty1390",

language = "English (US)",

volume = "478",

pages = "4866--4880",

journal = "Monthly Notices of the Royal Astronomical Society",

issn = "0035-8711",

publisher = "Oxford University Press",

number = "4",

}

Van Eylen, V, Dai, F, Mathur, S, Gandolfi, D, Albrecht, S, Fridlund, M, García, RA, Guenther, E, Hjorth, M, Justesen, AB, Livingston, J, Lund, MN, Pérez Hernández, F, Prieto-Arranz, J, Regulo, C, Bugnet, L, Everett, ME, Hirano, T, Nespral, D, Nowak, G, Palle, E, Silva Aguirre, V, Trifonov, T, Winn, JN, Barragán, O, Beck, PG, Chaplin, WJ, Cochran, WD, Csizmadia, S, Deeg, H, Endl, M, Heeren, P, Grziwa, S, Hatzes, AP, Hidalgo, D, Korth, J, Mathis, S, Rodriguez, PM, Narita, N, Patzold, M, Persson, CM, Rodler, F & Smith, AMS 2018, 'HD 89345: A bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2', Monthly Notices of the Royal Astronomical Society, vol. 478, no. 4, pp. 4866-4880. https://doi.org/10.1093/mnras/sty1390

TY - JOUR

T1 - HD 89345

T2 - A bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2

AU - Van Eylen, V.

AU - Dai, F.

AU - Mathur, S.

AU - Gandolfi, D.

AU - Albrecht, S.

AU - Fridlund, M.

AU - García, R. A.

AU - Guenther, E.

AU - Hjorth, M.

AU - Justesen, A. B.

AU - Livingston, J.

AU - Lund, M. N.

AU - Pérez Hernández, F.

AU - Prieto-Arranz, J.

AU - Regulo, C.

AU - Bugnet, L.

AU - Everett, M. E.

AU - Hirano, T.

AU - Nespral, D.

AU - Nowak, G.

AU - Palle, E.

AU - Silva Aguirre, V.

AU - Trifonov, T.

AU - Winn, J. N.

AU - Barragán, O.

AU - Beck, P. G.

AU - Chaplin, W. J.

AU - Cochran, W. D.

AU - Csizmadia, S.

AU - Deeg, H.

AU - Endl, M.

AU - Heeren, P.

AU - Grziwa, S.

AU - Hatzes, A. P.

AU - Hidalgo, D.

AU - Korth, J.

AU - Mathis, S.

AU - Rodriguez, P. Montañes

AU - Narita, N.

AU - Patzold, M.

AU - Persson, C. M.

AU - Rodler, F.

AU - Smith, A. M.S.

PY - 2018/8/21

Y1 - 2018/8/21

N2 - We report the discovery and characterization of HD 89345b (K2-234b; EPIC 248777106b), a Saturn-sized planet orbiting a slightly evolved star. HD 89345 is a bright star (V = 9.3 mag) observed by the K2 mission with 1 min time sampling. It exhibits solar-like oscillations. We conducted asteroseismology to determine the parameters of the star, finding themass and radius to be 1.12-0.01+0.04 M⊙ and 1.657 -0.004 +0.020 R⊙, respectively. The star appears to have recently left the main sequence, based on the inferred age, 9.4-1.3+0.4 Gyr, and the non-detection of mixed modes. The star hosts a 'warm Saturn' (P = 11.8 d, Rp = 6.86 ± 0.14 R⊕). Radial-velocity follow-up observations performed with the FIbre-fed Echelle Spectrograph, HARPS, and HARPS-N spectrographs show that the planet has a mass of 35.7 ± 3.3 M⊕. The data also show that the planet's orbit is eccentric (e≈0.2). An investigation of the rotational splitting of the oscillation frequencies of the star yields no conclusive evidence on the stellar inclination angle. We further obtained Rossiter-McLaughlin observations, which result in a broad posterior of the stellar obliquity. The planet seems to confirm to the same patterns that have been observed for other sub-Saturns regarding planet mass and multiplicity, orbital eccentricity, and stellar metallicity.

AB - We report the discovery and characterization of HD 89345b (K2-234b; EPIC 248777106b), a Saturn-sized planet orbiting a slightly evolved star. HD 89345 is a bright star (V = 9.3 mag) observed by the K2 mission with 1 min time sampling. It exhibits solar-like oscillations. We conducted asteroseismology to determine the parameters of the star, finding themass and radius to be 1.12-0.01+0.04 M⊙ and 1.657 -0.004 +0.020 R⊙, respectively. The star appears to have recently left the main sequence, based on the inferred age, 9.4-1.3+0.4 Gyr, and the non-detection of mixed modes. The star hosts a 'warm Saturn' (P = 11.8 d, Rp = 6.86 ± 0.14 R⊕). Radial-velocity follow-up observations performed with the FIbre-fed Echelle Spectrograph, HARPS, and HARPS-N spectrographs show that the planet has a mass of 35.7 ± 3.3 M⊕. The data also show that the planet's orbit is eccentric (e≈0.2). An investigation of the rotational splitting of the oscillation frequencies of the star yields no conclusive evidence on the stellar inclination angle. We further obtained Rossiter-McLaughlin observations, which result in a broad posterior of the stellar obliquity. The planet seems to confirm to the same patterns that have been observed for other sub-Saturns regarding planet mass and multiplicity, orbital eccentricity, and stellar metallicity.

KW - Asteroseismology

KW - Planets and satellites: composition

KW - Planets and satellites: formation

KW - Planets and satellites: fundamental parameters

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U2 - 10.1093/mnras/sty1390

DO - 10.1093/mnras/sty1390

M3 - Article

AN - SCOPUS:85050797619

SN - 0035-8711

VL - 478

SP - 4866

EP - 4880

JO - Monthly Notices of the Royal Astronomical Society

JF - Monthly Notices of the Royal Astronomical Society

IS - 4

ER -

HD 89345: A bright oscillating star hosting a transiting warm Saturn-sized planet observed by K2

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