Rapid evolution of the innermost dust disc of protoplanetary discs surrounding intermediate-mass stars
Abstract
We derived the intermediate-mass (≃1.5-7 M⊙) disc fraction (IMDF) in the near-infrared JHK photometric bands as well as in the mid-infrared (MIR) bands for young clusters in the age range of 0 to ∼10 Myr. From the JHK IMDF, the lifetime of the innermost dust disc (∼0.3 au; hereafter the K disc) is estimated to be ∼3 Myr, suggesting a stellar mass (M*) dependence of K-disc lifetime (≃1.5-7 M⊙). However, from the MIR IMDF, the lifetime of the inner disc (∼5 au; hereafter the MIR disc) is estimated to be ∼6.5 Myr, suggesting a very weak stellar mass dependence (M*). The much shorter K-disc lifetime compared to the MIR-disc lifetime for intermediate-mass (IM) stars suggests that IM stars with transition discs, which have only MIR excess emission but no K-band excess emission, are more common than classical Herbig Ae/Be stars, which exhibit both. We suggest that this prominent early disappearance of the K disc for IM stars is due to dust settling/growth in the protoplanetary disc, and it could be one of the major reasons for the paucity of close-in planets around IM stars.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- August 2014
- DOI:
- 10.1093/mnras/stu1013
- arXiv:
- arXiv:1405.5284
- Bibcode:
- 2014MNRAS.442.2543Y
- Keywords:
-
- planets and satellites: formation;
- protoplanetary discs;
- circumstellar matter;
- stars: pre main-sequence;
- stars: variables: T Tauri;
- Herbig Ae/Be;
- infrared: stars;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 70 pages, 28 figures, and 23 tables. Accepted for publication in MNRAS