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HD 20329b: An ultra-short-period planet around a solar-type star found by TESS

Murgas, F. and Nowak, G. and Masseron, T. and Parviainen, H. and Luque, R. and Pallé, E. and Korth, J. and Carleo, I. and Csizmadia, Sz and Esparza-Borges, E. and Alqasim, A. and Cochran, W. D. and Dai, F. and Deeg, H. J. and Gandolfi, D. and Goffo, E. and Kabáth, P. and Lam, K. W. F. and Livingston, J. and Muresan, A. and Osborne, H. L. M. and Persson, C. M. and Serrano, L. M. and Smith, A. M. S. and Van Eylen, V. and Orell-Miquel, J. and Hinkel, N. R. and Galán, D. and Puig-Subirà, M. and Stangret, M. and Fukui, A. and Kagetani, T. and Narita, N. and Ciardi, D. R. and Boyle, A. W. and Ziegler, C. and Briceño, C. and Law, N. and Mann, A. W. and Jenkins, J. M. and Latham, D. W. and Quinn, S. N. and Ricker, G. and Seager, S. and Shporer, A. and Ting, E. B. and Vanderspek, R. and Winn, J. N. (2022) HD 20329b: An ultra-short-period planet around a solar-type star found by TESS. Astronomy and Astrophysics, 668 . Art. No. A158. ISSN 0004-6361. doi:10.1051/0004-6361/202244459.

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Context. Ultra-short-period (USP) planets are defined as planets with orbital periods shorter than one day. This type of planets is rare, highly irradiated, and interesting because their formation history is unknown. Aims. We aim to obtain precise mass and radius measurements to confirm the planetary nature of a USP candidate found by the Transiting Exoplanet Survey Satellite (TESS). These parameters can provide insights into the bulk composition of the planet candidate and help to place constraints on its formation history. Methods. We used TESS light curves and HARPS-N spectrograph radial velocity measurements to establish the physical properties of the transiting exoplanet candidate found around the star HD 20329 (TOI-4524). We performed a joint fit of the light curves and radial velocity time series to measure the mass, radius, and orbital parameters of the candidate. Results. We confirm and characterize HD 20329b, a USP planet transiting a solar-type star. The host star (HD 20329, V = 8.74 mag, J = 7.5 mag) is characterized by its G5 spectral type with M_* = 0.90 ± 0.05 M_⊙, R_* = 1.13 ± 0.02 R_⊙, and T_(eff) = 5596 ± 50 K; it is located at a distance d = 63.68 ± 0.29 pc. By jointly fitting the available TESS transit light curves and follow-up radial velocity measurements, we find an orbital period of 0.9261 ± (0.5 × 10⁻⁴) days, a planetary radius of 1.72 ± 0.07 R_⊗, and a mass of 7.42 ± 1.09 M_⊗, implying a mean density of ρ_p = 8.06 ± 1.53 g cm⁻³. HD 20329b joins the ~30 currently known USP planets with radius and Doppler mass measurements.

Item Type:Article
Related URLs:
URLURL TypeDescription
Murgas, F.0000-0001-9087-1245
Nowak, G.0000-0002-7031-7754
Masseron, T.0000-0002-6939-0831
Parviainen, H.0000-0001-5519-1391
Luque, R.0000-0002-4671-2957
Pallé, E.0000-0003-0987-1593
Korth, J.0000-0002-0076-6239
Carleo, I.0000-0002-0810-3747
Csizmadia, Sz0000-0001-6803-9698
Esparza-Borges, E.0000-0002-2341-3233
Cochran, W. D.0000-0001-9662-3496
Dai, F.0000-0002-8958-0683
Deeg, H. J.0000-0003-0047-4241
Gandolfi, D.0000-0001-8627-9628
Goffo, E.0000-0001-9670-961X
Kabáth, P.0000-0002-1623-5352
Lam, K. W. F.0000-0002-9910-6088
Livingston, J.0000-0002-4881-3620
Muresan, A.0000-0002-3439-4330
Osborne, H. L. M.0000-0002-4143-4767
Persson, C. M.0000-0003-1257-5146
Serrano, L. M.0000-0001-9211-3691
Smith, A. M. S.0000-0002-2386-4341
Van Eylen, V.0000-0001-5542-8870
Orell-Miquel, J.0000-0003-2066-8959
Hinkel, N. R.0000-0003-0595-5132
Galán, D.0000-0001-6191-8251
Puig-Subirà, M.0000-0001-8955-7574
Stangret, M.0000-0002-1812-8024
Fukui, A.0000-0002-4909-5763
Kagetani, T.0000-0002-5331-6637
Narita, N.0000-0001-8511-2981
Ciardi, D. R.0000-0002-5741-3047
Boyle, A. W.0000-0001-6037-2971
Ziegler, C.0000-0002-0619-7639
Briceño, C.0000-0001-7124-4094
Law, N.0000-0001-9380-6457
Mann, A. W.0000-0003-3654-1602
Jenkins, J. M.0000-0002-4715-9460
Latham, D. W.0000-0001-9911-7388
Quinn, S. N.0000-0002-8964-8377
Ricker, G.0000-0003-2058-6662
Seager, S.0000-0002-6892-6948
Shporer, A.0000-0002-1836-3120
Ting, E. B.0000-0002-8219-9505
Vanderspek, R.0000-0001-6763-6562
Winn, J. N.0000-0002-4265-047X
Additional Information:T.M. acknowledges financial support from the Spanish Ministry of Science and Innovation (MICINN) through the Spanish State Research Agency, under the Severo Ochoa Program 2020-2023 (CEX2019-000920-S) as well as support from the ACIISI, Consejería de Economía, Conocimiento y Empleo del Gobierno de Canarias and the European Regional Development Fund (ERDF) under grant with reference PROID2021010128. R.L. acknowledges funding from University of La Laguna through the Margarita Salas Fellowship from the Spanish Ministry of Universities ref. UNI/551/2021-May 26 under the EU Next Generation funds and financial support from the Spanish Ministerio de Ciencia e Innovación, through project PID2019-109522GB-C52, and the Centre of Excellence “Severo Ochoa” award to the Instituto de Astrofísica de Andalucía (SEV-2017-0709). PK acknolwedges the support from grant LTT-20015. K.W.F.L. was supported by Deutsche Forschungsgemeinschaft grants RA714/14-1 within the DFG Schwerpunkt SPP 1992, Exploring the Diversity of Extrasolar Planets. HJD acknowledges support from the Spanish Research Agency of the Ministry of Science and Innovation (AEI-MICINN) under the grant PID2019-107061GB-C66, DOI: 10.13039/501100011033. C.M.P. and J.K. gratefully acknowledge the support of the Swedish National Space Agency (DNR 65/19 2020-00104). This paper includes data collected by the TESS mission, which are publicly available from the Mikulski Archive for Space Telescopes (MAST). Funding for the TESS mission is provided by NASA’s Science Mission directorate. Resources supporting this work were provided by the NASA High-End Computing (HEC) Program through the NASA Advanced Supercomputing (NAS) Division at Ames Research Center for the production of the SPOC data products. We acknowledge the use of public TESS data from pipelines at the TESS Science Office and at the TESS Science Processing Operations Center. This research has made use of the Exoplanet Follow-up Observation Program website, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. This publication makes use of data products from the AAVSO Photometric All Sky Survey (APASS). Funded by the Robert Martin Ayers Sciences Fund and the National Science Foundation. This work has made use of data from the European Space Agency (ESA) mission Gaia (, processed by the Gaia Data Processing and Analysis Consortium (DPAC, Funding for the DPAC has been provided by national institutions, in particular the institutions participating in the Gaia Multilateral Agreement. This work made use of tpfplotter by J. Lillo-Box (publicly available in, which also made use of the python packages astropy, lightkurve, matplotlib and numpy. This work is partly supported by JSPS KAKENHI Grant Numbers JP17H04574, JP18H05442, JST CREST Grant Number JPMJCR1761, and the Astrobiology Center of National Institutes of Natural Sciences (NINS) (Grant Number AB031010). This paper is based on observations made with the MuSCAT2 instrument, developed by ABC, at Telescopio Carlos Sánchez operated on the island of Tenerife by the IAC in the Spanish Observatorio del Teide.
Funding AgencyGrant Number
Centro de Excelencia Severo OchoaCEX2019-000920-S
Agencia Canaria de Investigación, Innovación y Sociedad de la Información (ACIISI)UNSPECIFIED
European Regional Development FundPROID2021010128
Ministerio de UniversidadesUNI/551/2021-May 26
Ministerio de Ciencia e Innovación (MCINN)PID2019-109522GB-C52
Severo OchoaSEV-2017-0709
Ministry of Education, Youth and Sports (Czech Republic)LTT-20015
Deutsche Forschungsgemeinschaft (DFG)RA714/14-1
Ministerio de Ciencia e Innovación (MCINN)PID2019-107061GB-C66
Swedish National Space Agency65/19 2020-00104
Robert Martin Ayers Sciences FundUNSPECIFIED
Gaia Multilateral AgreementUNSPECIFIED
Japan Society for the Promotion of Science (JSPS)JP17H04574
Japan Society for the Promotion of Science (JSPS)JP18H05442
Japan Science and Technology AgencyJPMJCR1761
National Institutes of Natural Sciences of JapanAB031010
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ID Code:119043
Deposited By: Research Services Depository
Deposited On:02 Mar 2023 18:18
Last Modified:02 Mar 2023 18:18

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