Testing the white dwarf mass-radius relationship with eclipsing binaries
Abstract
We present high-precision, model-independent, mass and radius measurements for 16 white dwarfs in detached eclipsing binaries and combine these with previously published data to test the theoretical white dwarf mass-radius relationship. We reach a mean precision of 2.4 per cent in mass and 2.7 per cent in radius, with our best measurements reaching a precision of 0.3 per cent in mass and 0.5 per cent in radius. We find excellent agreement between the measured and predicted radii across a wide range of masses and temperatures. We also find the radii of all white dwarfs with masses less than 0.48 M⊙ to be fully consistent with helium core models, but they are on average 9 per cent larger than those of carbon-oxygen core models. In contrast, white dwarfs with masses larger than 0.52 M⊙ all have radii consistent with carbon-oxygen core models. Moreover, we find that all but one of the white dwarfs in our sample have radii consistent with possessing thick surface hydrogen envelopes (10-5 ≥ MH/MWD ≥ 10-4), implying that the surface hydrogen layers of these white dwarfs are not obviously affected by common envelope evolution.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- October 2017
- DOI:
- 10.1093/mnras/stx1522
- arXiv:
- arXiv:1706.05016
- Bibcode:
- 2017MNRAS.470.4473P
- Keywords:
-
- binaries: eclipsing;
- stars: fundamental parameters;
- stars: interiors;
- white dwarfs;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- Accepted for publication in MNRAS