13C17O suggests gravitational instability in the HL Tau disc
Abstract
We present the first detection of the ^{13}C^{17}O J = 3-2 transition toward the HL Tau protoplanetary disc. We find significantly more gas mass (at least a factor of 10 higher) than has been previously reported using C^{18}O emission. This brings the observed total disc mass to 0.2 M⊙, which we consider to be a conservative lower limit. Our analysis of the Toomre Q profile suggests that this brings the disc into the regime of gravitational instability. The radial region of instability (50-110 au) coincides with the location of a proposed planet-carved gap in the dust disc, and a spiral in the gas. We therefore propose that if the origin of the gap is confirmed to be due to a forming giant planet, then it is likely to have formed via the gravitational fragmentation of the protoplanetary disc.
- Publication:
-
Monthly Notices of the Royal Astronomical Society
- Pub Date:
- March 2020
- DOI:
- 10.1093/mnrasl/slaa014
- arXiv:
- arXiv:2001.07550
- Bibcode:
- 2020MNRAS.493L.108B
- Keywords:
-
- techniques: interferometric;
- protoplanetary discs;
- stars: individual: HL Tau;
- stars: pre-main-sequence;
- submillimetre: planetary systems;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Earth and Planetary Astrophysics;
- Astrophysics - Astrophysics of Galaxies
- E-Print:
- Accepted 2020 January 21. Received 2020 January 21