Deep Imaging Search for Planets Forming in the TW Hya Protoplanetary Disk with the Keck/NIRC2 Vortex Coronagraph
Abstract
Distinct gap features in the nearest protoplanetary disk, TW Hya (distance of 59.5 ± 0.9 pc), may be signposts of ongoing planet formation. We performed long-exposure thermal infrared coronagraphic imaging observations to search for accreting planets, especially within dust gaps previously detected in scattered light and submillimeter-wave thermal emission. Three nights of observations with the Keck/NIRC2 vortex coronagraph in L‧ (3.4-4.1 μm) did not reveal any statistically significant point sources. We thereby set strict upper limits on the masses of non-accreting planets. In the four most prominent disk gaps at 24, 41, 47, and 88 au, we obtain upper mass limits of 1.6-2.3, 1.1-1.6, 1.1-1.5, and 1.0-1.2 Jupiter masses (M J), assuming an age range of 7-10 Myr for TW Hya. These limits correspond to the contrast at 95% completeness (true positive fraction of 0.95) with a 1% chance of a false positive within 1″ of the star. We also approximate an upper limit on the product of the planet mass and planetary accretion rate of {M}{{p}}\dot{M}≲ {10}-8 {M}{{J}}2 {yr}}-1 implying that any putative ∼0.1 M J planet, which could be responsible for opening the 24 au gap, is presently accreting at rates insufficient to build up a Jupiter mass within TW Hya’s pre-main-sequence lifetime.
- Publication:
-
The Astronomical Journal
- Pub Date:
- August 2017
- DOI:
- 10.3847/1538-3881/aa7b81
- arXiv:
- arXiv:1706.07489
- Bibcode:
- 2017AJ....154...73R
- Keywords:
-
- circumstellar matter;
- stars: individual: TW Hya;
- stars: pre-main sequence;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- The Astronomical Journal 154, 73 (2017)