The dot{M}-M_* relation of pre-main-sequence stars: a consequence of X-ray driven disc evolution
Abstract
We analyse current measurements of accretion rates on to pre-main-sequence stars as a function of stellar mass, and conclude that the steep dependence of accretion rates on stellar mass is real and not driven by selection/detection threshold, as has been previously feared. These conclusions are reached by means of statistical tests including a survival analysis which can account for upper limits. The power-law slope of the dot{M}-M_* relation is found to be in the range of 1.6-1.9 for young stars with masses lower than 1 M⊙. The measured slopes and distributions can be easily reproduced by means of a simple disc model which includes viscous accretion and X-ray photoevaporation. We conclude that the dot{M}-M_* relation in pre-main-sequence stars bears the signature of disc dispersal by X-ray photoevaporation, suggesting that the relation is a straightforward consequence of disc physics rather than an imprint of initial conditions.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- March 2014
- DOI:
- 10.1093/mnras/stt2405
- arXiv:
- arXiv:1312.3154
- Bibcode:
- 2014MNRAS.439..256E
- Keywords:
-
- radiative transfer;
- protoplanetary discs;
- dust;
- extinction;
- infrared: stars;
- Astrophysics - Solar and Stellar Astrophysics
- E-Print:
- 9 pages, 6 Figures, 2 Tables, accepted by MNRAS