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The TEXES Survey for H2 Emission from Protoplanetary Disks

Bitner, Martin A. and Richter, Matthew J. and Lacy, John H. and Herczeg, Gregory J. and Greathouse, Thomas K. and Jaffe, Daniel T. and Salyk, Colette and Blake, Geoffrey A. and Hollenbach, David J. and Doppmann, Greg W. and Najita, Joan R. and Currie, Thayne (2008) The TEXES Survey for H2 Emission from Protoplanetary Disks. Astrophysical Journal, 688 (2). pp. 1326-1344. ISSN 0004-637X.

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We report the results of a search for pure rotational molecular hydrogen emission from the circumstellar environments of young stellar objects with disks using the Texas Echelon Cross Echelle Spectrograph (TEXES) on the NASA Infrared Telescope Facility and the Gemini North Observatory. We searched for mid-infrared H2 emission in the S(1), S(2), and S(4) transitions. Keck/NIRSPEC observations of the H2 S(9) transition were included for some sources as an additional constraint on the gas temperature. We detected H2 emission from 6 of 29 sources observed: AB Aur, DoAr 21, Elias 29, GSS 30 IRS 1, GV Tau N, and HL Tau. Four of the six targets with detected emission are class I sources that show evidence for surrounding material in an envelope in addition to a circumstellar disk. In these cases, we show that accretion shock heating is a plausible excitation mechanism. The detected emission lines are narrow (~10 km s^−1), centered at the stellar velocity, and spatially unresolved at scales of 0.4", which is consistent with origin from a disk at radii 10–50 AU from the star. In cases where we detect multiple emission lines, we derive temperatures 500 K from ~1 M⊕ of gas. Our upper limits for the nondetections place upper limits on the amount of H2 gas with T > K of less than a few Earth masses. Such warm gas temperatures are significantly higher than the equilibrium dust temperatures at these radii, suggesting that the gas is decoupled from the dust in the regions that we are studying and that processes such as UV, X-ray, and accretion heating may be important.

Item Type:Article
Related URLs:
URLURL TypeDescription
Richter, Matthew J.0000-0002-8594-2122
Lacy, John H.0000-0001-6783-2328
Herczeg, Gregory J.0000-0002-7154-6065
Jaffe, Daniel T.0000-0003-3577-3540
Salyk, Colette0000-0003-3682-6632
Blake, Geoffrey A.0000-0003-0787-1610
Currie, Thayne0000-0002-7405-3119
Additional Information:© 2008. The American Astronomical Society. Received 2008 April 8; accepted 2008 July 31. The authors wish to recognize and acknowledge the very significant cultural role and reverence that the summit of Mauna Kea has always had within the indigenous Hawaiian community. We are most fortunate to have the opportunity to conduct observations from this mountain. We thank the Gemini staff, and John White in particular, for their support of TEXES observations on Gemini North. The development of TEXES was supported by grants from the NSF and the NASA/USRA SOFIA project. Modification of TEXES for use on Gemini was supported by Gemini Observatory. Observations with TEXES were supported by NSF grant AST 06-07312. M. J. R. acknowledges support from NSF grant AST 07-08074 and NASA grant NNG04GG92G. Some of the data presented herein were obtained at the W. M. Keck Observatory, which is operated as a scientific partnership among the California Institute of Technology, the University of California, and the National Aeronautics and Space Administration. The Observatory was made possible by the generous financial support of the W. M. Keck Foundation. This work is based on observations obtained at the Gemini Observatory, which is operated by the Association of Universities for Research in Astronomy, Inc., under a cooperative agreement with the NSF on behalf of the Gemini partnership: the National Science Foundation (United States), the Particle Physics and Astronomy Research Council (United Kingdom), the National Research Council (Canada), CONICYT (Chile), the Australian Research Council (Australia), CNPq (Brazil), and CONICET (Argentina).
Funding AgencyGrant Number
NSFAST 06-07312
NSFAST 07-08074
W. M. Keck FoundationUNSPECIFIED
Particle Physics and Astronomy Research Council (PPARC)UNSPECIFIED
National Research Council of CanadaUNSPECIFIED
Comisión Nacional de Investigación Científica y Tecnológica (CONICYT)UNSPECIFIED
Australian Research CouncilUNSPECIFIED
Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)UNSPECIFIED
Consejo Nacional de Investigaciones Científicas y Técnicas (CONICET)UNSPECIFIED
Subject Keywords:circumstellar matter; infrared: stars; planetary systems: protoplanetary disks; stars: individual (AB Aur, DoAr 21, Elias 29, GSS 30 IRS 1, GV Tau N, HL Tau); stars: pre-main-sequence
Issue or Number:2
Record Number:CaltechAUTHORS:BITapj08
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Usage Policy:No commercial reproduction, distribution, display or performance rights in this work are provided.
ID Code:12561
Deposited By: Archive Administrator
Deposited On:16 Dec 2008 00:30
Last Modified:09 Mar 2020 13:18

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