MOLECULAR HYDROGEN IN THE DISK OF THE HERBIG Ae STAR HD 97048

Journal Article · Mon Apr 20 04:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/695/2/1302; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21296242

Martin-Zaidi, C; Augereau, J -C; Menard, F; Olofsson, J ^[1]; Habart, E ^[2]; Lagage, P- O

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1. Laboratoire d'Astrophysique de Grenoble, CNRS/UJF - UMR 5571, 414 rue de la Piscine, DU Saint Martin d'Heres, 38041 Grenoble cedex 9 (France)
2. Institut d'Astrophysique Spatiale, 91405 Orsay (France)

We present high-resolution spectroscopic mid-infrared observations of the circumstellar (CS) disk around the Herbig Ae star HD 97048 obtained with the VLT Imager and Spectrometer for the Mid-InfraRed. We conducted observations of mid-infrared pure rotational lines of molecular hydrogen (H{sub 2}) as a tracer of warm gas in the disk surface layers. In a previous paper, we reported the detection of the S(1) pure rotational line of H{sub 2} at 17.035 {mu}m, and argued that it is arising from the inner regions of the disk around the star. We used the VISIR on the VLT for a more comprehensive study based on complementary observations of the other mid-infrared molecular transitions, namely S(2) and S(4) at 12.278 {mu}m and 8.025 {mu}m respectively, to investigate the physical properties of the molecular gas in the CS disk around HD 97048. We do not detect either the S(2) line or the S(4) H{sub 2} line from the disk of HD 97048, but we derive upper limits on the integrated line fluxes which allows us to estimate an upper limit on the gas excitation temperature, T {sub ex} < 570 K. This limit on the temperature is consistent with the assumptions previously used in the analysis of the S(1) line, and allows us to set stronger constraints on the mass of warm gas in the inner regions of the disk. Indeed, we estimate the mass of warm gas to be lower than 0.1 M {sub Jup}. We also discuss the probable physical mechanisms which could be responsible for the excitation of H{sub 2} in the disk of HD 97048.

• OSTI ID: 21296242
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 2 Vol. 695; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

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