First radius measurements of very low mass stars with the VLTI
Abstract
We present 4 very low mass stars radii measured with the VLTI using the 2.2 mu m VINCI test instrument. The observations were carried out during the commissioning of the 104-meter-baseline with two 8-meter-telescopes. We measure angular diameters of 0.7-1.5 mas with accuracies of 0.04-0.11 mas, and for spectral type ranging from M0V to M5.5V. We determine an empirical mass-radius relation for M dwarfs based on all available radius measurements. The observed relation agrees well with theoretical models at the present accuracy level, with possible discrepancy around 0.5-0.8 Msun that needs to be confirmed. In the near future, dozens of M dwarfs radii will be measured with 0.1-1% accuracy, with the VLTI, thanks to the improvements expected from the near infrared instrument AMBER. This will bring strong observational constraints on both atmosphere and interior physics.
Based on observations made with the European Southern Observatory telescopes and obtained from the ESO/ST-ECF Science Archive Facility.- Publication:
-
Astronomy and Astrophysics
- Pub Date:
- January 2003
- DOI:
- 10.1051/0004-6361:20021714
- arXiv:
- arXiv:astro-ph/0211647
- Bibcode:
- 2003A&A...397L...5S
- Keywords:
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- stars: low-mass;
- brown dwarfs;
- stars: fundamental parameters;
- techniques: interferometric;
- Astrophysics
- E-Print:
- Accepted for publication in Astronomy and Astrophysics Letters, 4 pages, 3 figures