---
_id: '11620'
abstract:
- lang: eng
  text: 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 the mass and radius to be 1.12+0.04−0.01M⊙ and 1.657+0.020−0.004R⊙⁠,
    respectively. The star appears to have recently left the main sequence, based
    on the inferred age, 9.4+0.4−1.3Gyr⁠, 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.
acknowledgement: 'We gratefully acknowledge many helpful suggestions by the anonymous
  referee. Based on observations made with a) the Nordic Optical Telescope, operated
  by the Nordic Optical Telescope Scientific Association at the Observatorio del Roque
  de los Muchachos; b) the ESO-3.6m telescope at La Silla Observatory under programme
  ID 0100.C-0808; c) the Italian Telescopio Nazionale Galileo operated on the island
  of La Palma by the Fundación Galileo Galilei of the Istituto Nazionale di Astrofisica.
  NESSI was funded by the NASA Exoplanet Exploration Program and the NASA Ames Research
  Center. NESSI was built at the Ames Research Center by Steve B. Howell, Nic Scott,
  Elliott P. Horch, and Emmett Quigley. This project has received funding from the
  European Union’s Horizon 2020 research and innovation programme under grant agreement
  No 730890. This material reflects only the authors views and the Commission is not
  liable for any use that may be made of the information contained therein. DG gratefully
  acknowledges the financial support of the Programma Giovani Ricercatori – Rita Levi
  Montalcini – Rientro dei Cervelli (2012) awarded by the Italian Ministry of Education,
  Universities and Research (MIUR). SaM would like to acknowledge support from the
  Ramon y Cajal fellowship number RYC-2015-17697. AJ, MH, and SA acknowledge support
  by the Danish Council for Independent Research, through a DFF Sapere Aude Starting
  Grant nr. 4181-00487B. SzCs, APH, MP, and HR acknowledge the support of the DFG
  priority program SPP 1992Exploring the Diversity of Extrasolar Planets (grants HA
  3279/12-1, PA 525/18-1, PA5 25/19-1 and PA525/20-1, RA 714/14-1) HD, CR, and FPH
  acknowledge the financial support from MINECO under grants ESP2015-65712-C5-4-R
  and AYA2016-76378-P. This paper has made use of the IAC Supercomputing facility
  HTCondor (http://research.cs.wisc.edu/htcondor/), partly financed by the Ministry
  of Economy and Competitiveness with FEDER funds, code IACA13-3E-2493. MF and CMP
  gratefully acknowledge the support of the Swedish National Space Board. RAG and
  StM thanks the support of the CNES PLATO grant. PGB is a postdoctoral fellow in
  the MINECO-programme ’Juan de la Cierva Incorporacion’ (IJCI-2015-26034). StM acknowledges
  support from ERC through SPIRE grant (647383) and from ISSI through the ENCELADE
  2.0 team. VSA acknowledges support from VILLUM FONDEN (research grant 10118). MNL
  acknowledges support from the ESA-PRODEX programme. Funding for the Stellar Astrophysics
  Centre is provided by The Danish National Research Foundation (Grant agreement no.:
  DNRF106) This work has made use of data from the European Space Agency (ESA) mission
  Gaia (https://www.cosmos.esa.int/gaia), processed by the Gaia Data Processing and
  Analysis Consortium (DPAC, https://www.cosmos.esa.int/web/gaia/dpac/consortium).
  Funding for the DPAC has been provided by national institutions, in particular the
  institutions participating in the Gaia Multilateral Agreement. This research was
  made with the use of NASA’s Astrophysics Data System and the NASA Exoplanet Archive,
  which is operated by the California Institute of Technology, under contract with
  the National Aeronautics and Space Administration under the Exoplanet Exploration
  Program.'
article_processing_charge: No
article_type: original
arxiv: 1
author:
- first_name: V
  full_name: Van Eylen, V
  last_name: Van Eylen
- first_name: F
  full_name: Dai, F
  last_name: Dai
- first_name: S
  full_name: Mathur, S
  last_name: Mathur
- first_name: D
  full_name: Gandolfi, D
  last_name: Gandolfi
- first_name: S
  full_name: Albrecht, S
  last_name: Albrecht
- first_name: M
  full_name: Fridlund, M
  last_name: Fridlund
- first_name: R A
  full_name: García, R A
  last_name: García
- first_name: E
  full_name: Guenther, E
  last_name: Guenther
- first_name: M
  full_name: Hjorth, M
  last_name: Hjorth
- first_name: A B
  full_name: Justesen, A B
  last_name: Justesen
- first_name: J
  full_name: Livingston, J
  last_name: Livingston
- first_name: M N
  full_name: Lund, M N
  last_name: Lund
- first_name: F
  full_name: Pérez Hernández, F
  last_name: Pérez Hernández
- first_name: J
  full_name: Prieto-Arranz, J
  last_name: Prieto-Arranz
- first_name: C
  full_name: Regulo, C
  last_name: Regulo
- first_name: Lisa Annabelle
  full_name: Bugnet, Lisa Annabelle
  id: d9edb345-f866-11ec-9b37-d119b5234501
  last_name: Bugnet
  orcid: 0000-0003-0142-4000
- first_name: M E
  full_name: Everett, M E
  last_name: Everett
- first_name: T
  full_name: Hirano, T
  last_name: Hirano
- first_name: D
  full_name: Nespral, D
  last_name: Nespral
- first_name: G
  full_name: Nowak, G
  last_name: Nowak
- first_name: E
  full_name: Palle, E
  last_name: Palle
- first_name: V
  full_name: Silva Aguirre, V
  last_name: Silva Aguirre
- first_name: T
  full_name: Trifonov, T
  last_name: Trifonov
- first_name: J N
  full_name: Winn, J N
  last_name: Winn
- first_name: O
  full_name: Barragán, O
  last_name: Barragán
- first_name: P G
  full_name: Beck, P G
  last_name: Beck
- first_name: W J
  full_name: Chaplin, W J
  last_name: Chaplin
- first_name: W D
  full_name: Cochran, W D
  last_name: Cochran
- first_name: S
  full_name: Csizmadia, S
  last_name: Csizmadia
- first_name: H
  full_name: Deeg, H
  last_name: Deeg
- first_name: M
  full_name: Endl, M
  last_name: Endl
- first_name: P
  full_name: Heeren, P
  last_name: Heeren
- first_name: S
  full_name: Grziwa, S
  last_name: Grziwa
- first_name: A P
  full_name: Hatzes, A P
  last_name: Hatzes
- first_name: D
  full_name: Hidalgo, D
  last_name: Hidalgo
- first_name: J
  full_name: Korth, J
  last_name: Korth
- first_name: S
  full_name: Mathis, S
  last_name: Mathis
- first_name: P
  full_name: Montañes Rodriguez, P
  last_name: Montañes Rodriguez
- first_name: N
  full_name: Narita, N
  last_name: Narita
- first_name: M
  full_name: Patzold, M
  last_name: Patzold
- first_name: C M
  full_name: Persson, C M
  last_name: Persson
- first_name: F
  full_name: Rodler, F
  last_name: Rodler
- first_name: A M S
  full_name: Smith, A M S
  last_name: Smith
citation:
  ama: 'Van Eylen V, Dai F, Mathur S, et al. HD 89345: A bright oscillating star hosting
    a transiting warm Saturn-sized planet observed by K2. <i>Monthly Notices of the
    Royal Astronomical Society</i>. 2018;478(4):4866-4880. doi:<a href="https://doi.org/10.1093/mnras/sty1390">10.1093/mnras/sty1390</a>'
  apa: 'Van Eylen, V., Dai, F., Mathur, S., Gandolfi, D., Albrecht, S., Fridlund,
    M., … Smith, A. M. S. (2018). HD 89345: A bright oscillating star hosting a transiting
    warm Saturn-sized planet observed by K2. <i>Monthly Notices of the Royal Astronomical
    Society</i>. Oxford University Press. <a href="https://doi.org/10.1093/mnras/sty1390">https://doi.org/10.1093/mnras/sty1390</a>'
  chicago: 'Van Eylen, V, F Dai, S Mathur, D Gandolfi, S Albrecht, M Fridlund, R A
    García, et al. “HD 89345: A Bright Oscillating Star Hosting a Transiting Warm
    Saturn-Sized Planet Observed by K2.” <i>Monthly Notices of the Royal Astronomical
    Society</i>. Oxford University Press, 2018. <a href="https://doi.org/10.1093/mnras/sty1390">https://doi.org/10.1093/mnras/sty1390</a>.'
  ieee: 'V. Van Eylen <i>et al.</i>, “HD 89345: A bright oscillating star hosting
    a transiting warm Saturn-sized planet observed by K2,” <i>Monthly Notices of the
    Royal Astronomical Society</i>, vol. 478, no. 4. Oxford University Press, pp.
    4866–4880, 2018.'
  ista: '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 LA, 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, Montañes Rodriguez P, 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. 478(4), 4866–4880.'
  mla: 'Van Eylen, V., et al. “HD 89345: A Bright Oscillating Star Hosting a Transiting
    Warm Saturn-Sized Planet Observed by K2.” <i>Monthly Notices of the Royal Astronomical
    Society</i>, vol. 478, no. 4, Oxford University Press, 2018, pp. 4866–80, doi:<a
    href="https://doi.org/10.1093/mnras/sty1390">10.1093/mnras/sty1390</a>.'
  short: 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.A. 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, Monthly Notices of
    the Royal Astronomical Society 478 (2018) 4866–4880.
date_created: 2022-07-18T14:43:17Z
date_published: 2018-08-01T00:00:00Z
date_updated: 2022-08-22T07:45:38Z
day: '01'
doi: 10.1093/mnras/sty1390
extern: '1'
external_id:
  arxiv:
  - '1805.01860'
intvolume: '       478'
issue: '4'
keyword:
- Space and Planetary Science
- Astronomy and Astrophysics
- asteroseismology
- 'planets and satellites: composition'
- 'planets and satellites: formation'
- 'planets and satellites: fundamental parameters'
language:
- iso: eng
main_file_link:
- open_access: '1'
  url: https://arxiv.org/abs/1805.01860
month: '08'
oa: 1
oa_version: Preprint
page: 4866-4880
publication: Monthly Notices of the Royal Astronomical Society
publication_identifier:
  eissn:
  - 1365-2966
  issn:
  - 0035-8711
publication_status: published
publisher: Oxford University Press
quality_controlled: '1'
scopus_import: '1'
status: public
title: 'HD 89345: A bright oscillating star hosting a transiting warm Saturn-sized
  planet observed by K2'
type: journal_article
user_id: 2DF688A6-F248-11E8-B48F-1D18A9856A87
volume: 478
year: '2018'
...