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arXiv · 2201.10465

RW Aur A : SpeX Spectral Evidence for Differentiated Planetesimal Formation, Migration and Destruction in an 3 Myr Old Excited CTTS System

C. M. Lisse·M. L. Sitko·S. J. Wolk·H. M. Günther·S. Brittain·J. D. Green·J. Steckloff·B. Johnson·C. C. Espaillat·M. Koutoukali·S. Y. Moorman·A. P. Jackson
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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 5 different components: (1) a stable continuum from 0.7 - 1.3 um, with approx color temperature 4000K, produced by the CTTS photospheric surface; (2) variable hydrogen emission lines emitted from hot excited hydrogen in the CTTSs protostellar atmosphere/accretion envelope; (3) hot CO gas in the CTTSs protostellar atmosphere/accretion envelope; (4) highly variable 1.8-5.0 um thermal continuum emission with color temperature ranging from 1130 to 1650K, due to a surrounding accretion disk that is spatially variable and has an inner wall at r = 0.04 AU and T = 1650K, and outer edges at approx 1200K; and (5) transient, bifurcated signatures of abundant Fe II + associated SI, SiI, and SrI in the systems jet structures. The bifuracted signatures first appeared in 2015, but these collapsed and disappeared into a small single peak protostellar atmosphere feature by late 2020. The temporal evolution of RW Aur As 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 (1) a stable WTTS photospheric continuum from 0.7 - 1.3 um + (3) cold CO gas in absorption + (4) stable 1.8-5.0 um thermal disk continuum emission with color temperature approx 1650K.

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C. M. Lisse, M. L. Sitko, S. J. Wolk, H. M. Günther, S. Brittain, J. D. Green, J. Steckloff, B. Johnson, C. C. Espaillat, M. Koutoukali, S. Y. Moorman, A. P. Jackson. 2022-01-25. RW Aur A : SpeX Spectral Evidence for Differentiated Planetesimal Formation, Migration and Destruction in an 3 Myr Old Excited CTTS System. https://doi.org/10.3847/1538-4357/ac51e0

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