RW Aur A: SpeX Spectral Evidence for Differentiated Planetesimal Formation, Migration, and Destruction in an 3 Myr Old Excited CTTS System
Abstract
We present 2007-2020 SpeX VISNIR spectral monitoring of the highly variable RW Aur A CTTS. We find direct evidence for a highly excited, IR-bright, asymmetric, and time-variable system. Comparison of the spectral and temporal trends found determines five different components: (1) a stable continuum from 0.7 to 1.3 μm, with color temperature ~4000 K, produced by the CTTS photospheric surface; (2) variable hydrogen emission lines emitted from hot excited hydrogen in the CTTS's protostellar atmosphere/accretion envelope; (3) hot CO gas in the CTTS's protostellar atmosphere/accretion envelope; (4) highly variable 1.8-5.0 μm thermal continuum emission with color temperature ranging from 1130 to 1650 K, due to a surrounding accretion disk that is spatially variable and has an inner wall at r ~ 0.04 au and T ~ 1650 K and outer edges at ~1200 K; and (5) transient, bifurcated signatures of abundant Fe II + associated S I, Si I, and Sr I in the system's jet structures. The bifurcated signatures first appeared in 2015, but these collapsed and disappeared into a small single-peaked protostellar atmosphere feature by late 2020. The temporal evolution of RW Aur A's spectral signatures is consistent with a dynamically excited CTTS system forming differentiated Vesta-sized planetesimals in an asymmetric accretion disk and migrating them inward to be destructively accreted. By contrast, nearby coeval binary companion RW Aur B evinces only a stable WTTS photospheric continuum from 0.7 to 1.3 μm + cold CO gas in absorption + stable 1.8-5.0 μm thermal disk continuum emission with color temperature ~1650 K.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- April 2022
- DOI:
- 10.3847/1538-4357/ac51e0
- arXiv:
- arXiv:2201.10465
- Bibcode:
- 2022ApJ...928..189L
- Keywords:
-
- T Tauri stars;
- Irregular variable stars;
- Spectroscopy;
- Astronomical techniques;
- Near infrared astronomy;
- Planetary system formation;
- Protoplanetary disks;
- 1681;
- 865;
- 1558;
- 1684;
- 1093;
- 1257;
- 1300;
- Astrophysics - Solar and Stellar Astrophysics;
- Astrophysics - Earth and Planetary Astrophysics
- E-Print:
- 38 Pages, 16 Figures, 2 Tables, accepted for publication in Astrophys J. 24-Jan-2022