The mass-radius relationship for very low mass stars: Four new discoveries from the HATSouth Survey

G. Zhou, D. Bayliss, J. D. Hartman, G. A. Bakos, K. Penev, Z. Csubry, T. G. Tan, A. Jordán, L. Mancini, M. Rabus, R. Brahm, N. Espinoza, M. Mohler-Fischer, S. Ciceri, V. Suc, B. Csák, T. Henning, B. Schmidt

Research output: Contribution to journalArticlepeer-review

47 Scopus citations

Abstract

We report the discovery of four transiting F-M binary systems with companions between 0.1 and 0.2M⊙ in mass by the HATSouth survey. These systems have been characterized via a global analysis of the HATSouth discovery data, combined with high-resolution radial velocities and accurate transit photometry observations. We determined the masses and radii of the component stars using a combination of two methods: isochrone fitting of spectroscopic primary star parameters and equating spectroscopic primary star rotation velocity with spin-orbit synchronization. These new very low mass companions are HATS550- 016B (0.110+0.005 -0.006M⊙, 0.147+0.003 -0.004 R⊙), HATS551-019B (0.17+0.01 -0.01M⊙, 0.18+0.01 -0.01 R⊙), HATS551-021B (0.132+0.014 -0.005M⊙, 0.154+0.006 -0.008 R⊙) and HATS553-001B (0.20+0.01 -0.02M⊙, 0.22+0.01 -0.01 R⊙). We examine our sample in the context of the radius anomaly for fully convective low-mass stars. Combining our sample with the 13 other well-studied very low mass stars, we find a tentative 5 per cent systematic deviation between the measured radii and theoretical isochrone models.

Original languageEnglish
Pages (from-to)2831-2844
Number of pages14
JournalMonthly Notices of the Royal Astronomical Society
Volume437
Issue number3
DOIs
StatePublished - Jan 2014
Externally publishedYes

Keywords

  • Binaries
  • Eclipsing - stars
  • Low-mass.

Fingerprint

Dive into the research topics of 'The mass-radius relationship for very low mass stars: Four new discoveries from the HATSouth Survey'. Together they form a unique fingerprint.

Cite this