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Searching for H2 emission from protoplanetary disks using near- and mid-infrared high-resolution spectroscopy

Published online by Cambridge University Press:  01 October 2007

A. Carmona
Affiliation:
ISDC & Geneva Observatory, University of Geneva, chemin d'Ecogia 16, CH-1290 Versoix. Switzerland email: Andres.Carmona@obs.unige.ch Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany European Southern Observatory, Karl Schwarzschild Strasse 2, 85748 Garching bei München, Germany
M. E. van den Ancker
Affiliation:
European Southern Observatory, Karl Schwarzschild Strasse 2, 85748 Garching bei München, Germany
Th. Henning
Affiliation:
Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
Ya. Pavlyuchenkov
Affiliation:
Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
C. P. Dullemond
Affiliation:
Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
M. Goto
Affiliation:
Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
D. Fedele
Affiliation:
Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany European Southern Observatory, Karl Schwarzschild Strasse 2, 85748 Garching bei München, Germany Dipartimento di Astronomia, Università di Padova, Vicolo dell'Osservatorio 2, 35122 Padova, Italy
B. Stecklum
Affiliation:
Thüringer Landessternwarte Tautenburg, Sternwarte 5, 07778 Tautenburg, Germany
W. F-.Thi
Affiliation:
Royal Observatory Edinburgh, Blackford Hill, Edinburgh, EH9 3HJ, UK
J. Bouwman
Affiliation:
Max Planck Institute for Astronomy, Königstuhl 17, 69117 Heidelberg, Germany
L. B. F. M. Waters
Affiliation:
Astronomical Institute, University of Amsterdam, Kruislaan 403, NL-1098 SJ Amsterdam, The Netherlands, Instituut voor Sterrenkunde, Katholieke Universiteit Leuven, Celestijnenlaan 200B, B-3030 Heverlee, Belgium
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Abstract

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The mass and dynamics of protoplanetary disks are dominated by molecular hydrogen (H2). However, observationally very little is known about the H2. In this paper, we discuss two projects aimed to constrain the properties of H2 in the disk's planet forming region (R<50AU). First, we present a sensitive survey for pure-rotational H2 emission at 12.278 and 17.035 μm in a sample of nearby Herbig Ae/Be and T Tauri stars using VISIR, ESO's VLT high-resolution mid-infrared spectrograph. Second, we report on a search for H2 ro-vibrational emission at 2.1228, 2.2233 and 2.2477 μm in the classical T Tauri star LkHα 264 and the debris disk 49 Cet employing CRIRES, ESO's VLT high-resolution near-infrared spectrograph.

VISIR project: none of the sources show H2 mid-IR emission. The observed disks contain less than a few tenths of MJupiter of optically thin H2 at 150 K, and less than a few MEarth at T>300 K. % and higher T. Our non-detections are consistent with the low flux levels expected from the small amount of H2 gas in the surface layer of a Chiang and Goldreich (1997) Herbig Ae two-layer disk model. In our sources the H2 and dust in the surface layer have not significantly departed from thermal coupling (Tgas/Tdust<2) and the gas-to-dust ratio in the surface layer is very likely <1000.

CRIRES project: The H2 lines at 2.1218 μm and 2.2233 μm are detected in LkHα 264. An upper limit on the 2.2477 μm H2 line flux in LkHα 264 is derived. 49 Cet does not exhibit H2 emission in any of observed lines. There are a few MMoon of optically thin hot H2 in the inner disk (∼0.1 AU) of LkHα 264, and less than a tenth of a MMoon of hot H2 in the inner disk of 49 Cet. The shape of the 1–0 S(0) line indicates that LkHα disk is close to face-on (i<35o). The measured 1–0 S(0)/1–0 S(1) and 2–1 S(1)/1–0 S(1) line ratios in LkHα 264 indicate that the H2 is thermally excited at T<1500 K. The lack of H2 emission in the NIR spectra of 49 Cet and the absence of Hα emission suggest that the gas in the inner disk of 49 Cet has dissipated.

Type
Contributed Papers
Copyright
Copyright © International Astronomical Union 2008

References

Bary, J. S., Weintraub, D. A., & Kastner, J. H. 2002, ApJL, 576, L73CrossRefGoogle Scholar
Bary, J. S., Weintraub, D. A., & Kastner, J. H. 2003, ApJL, 586, 1136CrossRefGoogle Scholar
Bitner, M. A., Richter, M. J., Lacy, J. H., Greathouse, T. K., Jaffe, D. T., & Blake, G. A. 2007, ApJL, 661, L69CrossRefGoogle Scholar
Carmona, A., et al. 2008, A&A, 477, 839Google Scholar
Carmona, A., van den Ancker, M. E., Henning, T., Goto, M., Fedele, D., & Stecklum, B. 2007, A&A, 476, 853Google Scholar
Carr, J. S. 2005, in High Resolution Infrared Spectroscopy in Astronomy, Edited by Kufl, H.U., Siebenmorgen, R., and Moorwood, A.F.M.. Springer-Verlag Berlin/Heidelberg, 2005, p. 203.CrossRefGoogle Scholar
Chen, C. H., et al. 2006, ApJS, 166, 35CrossRefGoogle Scholar
Chiang, E. I. & Goldreich, P. 1997, ApJ, 490, 368CrossRefGoogle Scholar
Chiang, E. I., Joung, M. K., Creech-Eakman, M. J., Qi, C., Kessler, J. E., Blake, G. A., & van Dishoeck, E. F. 2001, ApJ, 547, 1077CrossRefGoogle Scholar
Cohen, M., & Kuhi, L. V. 1979, ApJS, 41, 743CrossRefGoogle Scholar
Dent, W. R. F., Greaves, J. S., & Coulson, I. M. 2005, MNRAS, 359, 663CrossRefGoogle Scholar
Dullemond, C. P., Dominik, C., & Natta, A. 2001, ApJ, 560, 957CrossRefGoogle Scholar
Glassgold, A. E., Najita, J. R., & Igea, J. 2007, ApJ, 656, 515CrossRefGoogle Scholar
Hollenbach, D., et al. 2005, ApJ, 631, 1180CrossRefGoogle Scholar
Howat, S. K. R., & Greaves, J. S. 2007, MNRAS, 379, 1658CrossRefGoogle Scholar
Itoh, Y., Sugitani, K., Ogura, K., & Tamura, M. 2003, PASJ, 55, L77CrossRefGoogle Scholar
Käufl, H. U. et al. 2004, SPIE, 5492, 1218Google Scholar
Lagage, P. O. et al. 2004, The Messenger, 117, 12.Google Scholar
Lahuis, F., van Dishoeck, E. F., Blake, G. A., Evans, N. J. II, Kessler-Silacci, J. E., & Pontoppidan, K. M. 2007, ApJ, 665, 492CrossRefGoogle Scholar
Lundin, L. K. VLT VISIR Pipeline User Manual. VLT-MAN-ESO-19500-3852. 2006Google Scholar
Martin-Zaïdi, C., Lagage, P.-O., Pantin, E., & Habart, E. 2007, ApJL, 666, L117CrossRefGoogle Scholar
Mouri, H. 1994, ApJ, 427, 777CrossRefGoogle Scholar
Najita, J. R., Carr, J. S., Glassgold, A. E., & Valenti, J. A. 2007, in Protostars and Planets, V, Edited by Reipurth, B., Jewitt, D., and Keil, K., University of Arizona Press, Tucson, 2007, p. 507–522Google Scholar
Nomura, H., Aikawa, Y., Tsujimoto, M., Nakagawa, Y., & Millar, T. J. 2007, ApJ, 661, 334CrossRefGoogle Scholar
Pascucci, I., et al. 2006, ApJ, 651, 1177CrossRefGoogle Scholar
Richter, M. J., Jaffe, D. T., Blake, G. A., & Lacy, J. H. 2002, ApJL, 572, L161CrossRefGoogle Scholar
Sako, S., Yamashita, T., Kataza, H., Miyata, T., Okamoto, Y. K., Honda, M., Fujiyoshi, T., & Onaka, T. 2005, ApJ, 620, 347CrossRefGoogle Scholar
Sheret, I., Ramsay Howat, S. K., & Dent, W. R. F. 2003, MNRAS, 343, L65CrossRefGoogle Scholar
Shukla, S. J., Bary, J. S., Weintraub, D. A., & Kastner, J. H. 2003, Bulletin of the American Astronomical Society, 35, 1209Google Scholar
Thi, W. F., et al. 2001, ApJ, 561, 1074CrossRefGoogle Scholar
Weintraub, D. A., Kastner, J. H., & Bary, J. S. 2000, ApJ, 541, 767CrossRefGoogle Scholar
Weintraub, D. A., Bary, J. S., Kastner, J. H., Shukla, S. J., & Chynoweth, K. 2005, Bulletin of the American Astronomical Society, 37, 1165Google Scholar
Zuckerman, B., Forveille, T., & Kastner, J.H. 1995, Nature, 373, 494CrossRefGoogle Scholar