CHARACTERIZING THE IYJ EXCESS CONTINUUM EMISSION IN T TAURI STARS

Journal Article · Fri Apr 01 00:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/730/2/73· OSTI ID:21574866

Fischer, William ^[1]; Edwards, Suzan ^[2]; Hillenbrand, Lynne ^[3]; Kwan, John ^[4]

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1. Department of Physics and Astronomy, University of Toledo, Toledo, OH 43606 (United States)
2. Five College Astronomy Department, Smith College, Northampton, MA 01063 (United States)
3. Department of Astronomy, California Institute of Technology, Pasadena, CA 91125 (United States)
4. Five College Astronomy Department, University of Massachusetts, Amherst, MA 01003 (United States)

We present the first characterization of the excess continuum emission of accreting T Tauri stars between optical and near-infrared wavelengths. With nearly simultaneous spectra from 0.48 to 2.4 {mu}m acquired with HIRES and NIRSPEC on Keck and SpeX on the Infrared Telescope Facility, we find significant excess continuum emission throughout this region, including the I, Y, and J bands, which are usually thought to diagnose primarily photospheric emission. The IYJ excess correlates with the excess in the V band, attributed to accretion shocks in the photosphere, and the excess in the K band, attributed to dust in the inner disk near the dust sublimation radius, but it is too large to be an extension of the excess from these sources. The spectrum of the excess emission is broad and featureless, suggestive of blackbody radiation with a temperature between 2200 and 5000 K. The luminosity of the IYJ excess is comparable to the accretion luminosity inferred from modeling the blue and ultraviolet excess emission and may require reassessment of disk accretion rates. The source of the IYJ excess is unclear. In stars of low accretion rate, the size of the emitting region is consistent with cooler material surrounding small hot accretion spots in the photosphere. However, for stars with high accretion rates, the projected area is comparable to or exceeds that of the stellar surface. We suggest that at least some of the IYJ excess emission arises in the dust-free gas inside the dust sublimation radius in the disk.

• OSTI ID: 21574866
• Journal Information: Astrophysical Journal, Vol. 730, Issue 2; Other Information: DOI: 10.1088/0004-637X/730/2/73; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTROPHYSICS
COSMOLOGY AND ASTRONOMY
ACCRETION DISKS
BLACKBODY RADIATION
DUSTS
EMISSION
LUMINOSITY
PHOTOSPHERE
STAR ACCRETION
SUBLIMATION
T TAURI STARS
ATMOSPHERES
BINARY STARS
ELECTROMAGNETIC RADIATION
ERUPTIVE VARIABLE STARS
EVAPORATION
EVOLUTION
OPTICAL PROPERTIES
PHASE TRANSFORMATIONS
PHYSICAL PROPERTIES
RADIATIONS
SOLAR ATMOSPHERE
STAR EVOLUTION
STARS
STELLAR ATMOSPHERES
VARIABLE STARS