A Caltech Library Service

Asteroseismology of iota Draconis and Discovery of an Additional Long-period Companion

Hill, Michelle L. and Kane, Stephen R. and Campante, Tiago L. and Li, Zhexing and Dalba, Paul A. and Brandt, Timothy D. and White, Timothy R. and Pope, Benjamin J. S. and Stassun, Keivan G. and Fulton, Benjamin J. and Corsaro, Enrico and Li, Tanda and Ong, J. M. Joel and Bedding, Timothy R. and Bossini, Diego and Buzasi, Derek L. and Chaplin, William J. and Cunha, Margarida S. and García, Rafael A. and Breton, Sylvain N. and Hon, Marc and Huber, Daniel and Jiang, Chen and Kayhan, Cenk and Kuszlewicz, James S. and Mathur, Savita and Serenelli, Aldo and Stello, Dennis (2021) Asteroseismology of iota Draconis and Discovery of an Additional Long-period Companion. Astronomical Journal, 162 (5). Art. No. 211. ISSN 0004-6256. doi:10.3847/1538-3881/ac1b31.

[img] PDF - Published Version
See Usage Policy.

[img] PDF - Accepted Version
See Usage Policy.


Use this Persistent URL to link to this item:


Giant stars as known exoplanet hosts are relatively rare due to the potential challenges in acquiring precision radial velocities and the small predicted transit depths. However, these giant host stars are also some of the brightest in the sky and so enable high signal-to-noise ratio follow-up measurements. Here, we report on new observations of the bright (V ∼ 3.3) giant star ι Draconis (ι Dra), known to host a planet in a highly eccentric ∼511 day period orbit. TESS observations of the star over 137 days reveal asteroseismic signatures, allowing us to constrain the stellar radius, mass, and age to ∼2%, ∼6%, and ∼28%, respectively. We present the results of continued radial-velocity monitoring of the star using the Automated Planet Finder over several orbits of the planet. We provide more precise planet parameters of the known planet and, through the combination of our radial-velocity measurements with Hipparcos and Gaia astrometry, we discover an additional long-period companion with an orbital period of ~68⁺⁶⁰₋₃₆ yr. Mass predictions from our analysis place this substellar companion on the border of the planet and brown dwarf regimes. The bright nature of the star combined with the revised orbital architecture of the system provides an opportunity to study planetary orbital dynamics that evolve as the star moves into the giant phase of its evolution.

Item Type:Article
Related URLs:
URLURL TypeDescription Paper
Hill, Michelle L.0000-0002-0139-4756
Kane, Stephen R.0000-0002-7084-0529
Campante, Tiago L.0000-0002-4588-5389
Li, Zhexing0000-0002-4860-7667
Dalba, Paul A.0000-0002-4297-5506
Brandt, Timothy D.0000-0003-2630-8073
White, Timothy R.0000-0002-6980-3392
Pope, Benjamin J. S.0000-0003-2595-9114
Stassun, Keivan G.0000-0002-3481-9052
Fulton, Benjamin J.0000-0003-3504-5316
Corsaro, Enrico0000-0001-8835-2075
Li, Tanda0000-0001-6396-2563
Ong, J. M. Joel0000-0001-7664-648X
Bedding, Timothy R.0000-0001-5222-4661
Bossini, Diego0000-0002-9480-8400
Buzasi, Derek L.0000-0002-1988-143X
Chaplin, William J.0000-0002-5714-8618
Cunha, Margarida S.0000-0001-8237-7343
García, Rafael A.0000-0002-8854-3776
Breton, Sylvain N.0000-0003-0377-0740
Hon, Marc0000-0003-2400-6960
Huber, Daniel0000-0001-8832-4488
Jiang, Chen0000-0002-7614-1665
Kayhan, Cenk0000-0001-9198-2289
Kuszlewicz, James S.0000-0002-3322-5279
Mathur, Savita0000-0002-0129-0316
Serenelli, Aldo0000-0001-6359-2769
Stello, Dennis0000-0002-4879-3519
Additional Information:© 2021. The American Astronomical Society. Received 2021 March 11; revised 2021 July 16; accepted 2021 July 27; published 2021 October 22. The results reported herein benefited from collaborations and/or information exchange within NASA's Nexus for Exoplanet System Science (NExSS) research coordination network sponsored by NASA's Science Mission Directorate. P.D. acknowledges support from a National Science Foundation Astronomy and Astrophysics Postdoctoral Fellowship under award AST-1903811. T.L.C. acknowledges support from the European Union's Horizon 2020 research and innovation program under the Marie Skłodowska-Curie grant agreement No. 792848 (PULSATION). T.L.C. is supported by Fundação para a Ciência e a Tecnologia (FCT) in the form of a work contract (CEECIND/00476/2018). C.K. acknowledges support by Erciyes University Scientific Research Projects Coordination Unit under grant No. MAP-2020-9749. T.L. acknowledges the funding from the European Research Council (ERC) under the European Union's Horizon 2020 research and innovation program (CartographY GA. 804752). D.B. and M.S.C. acknowledge supported by FCT through the research grants UIDB/04434/2020, UIDP/04434/2020 and PTDC/FIS-AST/30389/2017, and by FEDER—Fundo Europeu de Desenvolvimento Regional through COMPETE2020—Programa Operacional Competitividade e Internacionalização (grant: POCI-01-0145-FEDER-030389). M.S.C. is supported by national funds through FCT in the form of a work contract. R.A.G. and S.N.B. acknowledge the support of the PLATO and GOLF CNES grants. S.M. acknowledges the support from the Spanish Ministry of Science and Innovation with the Ramon y Cajal fellowship number RYC-2015-17697 and with the grant No. PID2019-107187GB-I00. D.H. acknowledges support from the Alfred P. Sloan Foundation, the National Aeronautics and Space Administration (80NSSC19K0379), and the National Science Foundation (AST-1717000). D.L.B. acknowledges support from the NASA TESS GI Program under awards 80NSSC18K1585 and 80NSSC19K0385. T.R.B. acknowledges support from the Australian Research Council (DP210103119). Software: RadVel (Fulton et al. 2018, lightkurve (Lightkurve Collaboration et al. 2018, 26 , DIAMONDS (Corsaro & De Ridder 2014, Background extension to DIAMONDS (Corsaro & De Ridder 2014, FAMED (Corsaro et al. 2020, REBOUND: MEGNO (Rein & Liu 2012, The Joker (Price-Whelan et al. 2017, htof [Brandt et al. submitted] (, orvara (Brandt et al. 2021,
Group:Infrared Processing and Analysis Center (IPAC)
Funding AgencyGrant Number
NSF Astronomy and Astrophysics FellowshipAST-1903811
Marie Curie Fellowship792848
Fundação para a Ciência e a Tecnologia (FCT)CEECIND/00476/2018
Erciyes University Scientific Research ProjectsMAP-2020-9749
European Research Council (ERC)804752
Fundação para a Ciência e a Tecnologia (FCT)UIDB/04434/2020
Fundação para a Ciência e a Tecnologia (FCT)UIDP/04434/2020
Fundação para a Ciência e a Tecnologia (FCT)PTDC/FIS-AST/30389/2017
Fondo Europeo de Desarrollo Regional (FEDER)COMPETE2020
Fondo Europeo de Desarrollo Regional (FEDER)POCI-01-0145-FEDER-030389
Centre National d'Études Spatiales (CNES)UNSPECIFIED
Ramón y Cajal ProgrammeRYC-2015-17697
Ministerio de Ciencia e Innovación (MCINN)PID2019-107187GB-I00
Alfred P. Sloan FoundationUNSPECIFIED
Australian Research CouncilDP210103119
Subject Keywords:Photometry; Radial velocity; Exoplanet dynamics; Exoplanets; Exoplanet astronomy; Exoplanet systems; Exoplanet detection methods; Planet hosting stars; Asteroseismology; Stellar astronomy; Planetary dynamics; Detection
Issue or Number:5
Classification Code:Unified Astronomy Thesaurus concepts: Photometry (1234); Radial velocity (1332); Exoplanet dynamics (490); Exoplanets (498); Exoplanet astronomy (486); Exoplanet systems (484); Exoplanet detection methods (489); Planet hosting stars (1242)
Record Number:CaltechAUTHORS:20211115-234332784
Persistent URL:
Official Citation:Michelle L. Hill et al 2021 AJ 162 211
Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:111881
Deposited By: Tony Diaz
Deposited On:16 Nov 2021 17:37
Last Modified:16 Nov 2021 17:37

Repository Staff Only: item control page