Publikationsdatum:
2013-12-23
Beschreibung:
We report the discovery of four transiting F-M binary systems with companions between 0.1 and 0.2 M 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 ( $0.110_{-0.006}^{+0.005}\,\mathrm{M}_{\odot }$ , $0.147_{-0.004}^{+0.003}\,\mathrm{R}_{\odot }$ ), HATS551-019B ( $0.17_{-0.01}^{+0.01}\,\mathrm{M}_{\odot }$ , $0.18_{-0.01}^{+0.01}\,\mathrm{R}_{\odot }$ ), HATS551-021B ( $0.132_{-0.005}^{+0.014}\,\mathrm{M}_{\odot }$ , $0.154_{-0.008}^{+0.006}\,\mathrm{R}_{\odot }$ ) and HATS553-001B ( $0.20_{-0.02}^{+0.01}\,\mathrm{M}_{\odot }$ , $0.22_{-0.01}^{+0.01}\,\mathrm{R}_{\odot }$ ). 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.
Print ISSN:
0035-8711
Digitale ISSN:
1365-2966
Thema:
Physik
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