TRACING THE INNER EDGE OF THE DISK AROUND HD 100546 WITH ROVIBRATIONAL CO EMISSION LINES

Journal Article · Tue Sep 01 04:00:00 EDT 2009 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/702/1/85; COUNTRY OF INPUT: INTERNATIONAL ATOMIC ENERGY AGENCY (IAEA)· OSTI ID:21333869

Brittain, Sean D ^[1]; Najita, Joan R ^[2]

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1. Department of Physics and Astronomy, 118 Kinard Laboratory, Clemson University, Clemson, SC 29634 (United States)
2. National Optical Astronomy Observatory, 950 North Cherry Avenue, Tucson, AZ 85719 (United States)

In this paper we present high-resolution 4.7 {mu}m spectra of the isolated Herbig Be star HD 100546. HD 100546 has been the subject of intense scrutiny because it is a young nearby star with a transitional disk. We observe the {delta}v = 1 rovibrational CO transitions in order to clarify the distribution of warm gas in the inner disk. Modeling of the CO spectrum indicates that the gas is vibrationally excited by collisions and UV fluorescence. The observed emission extends from 13 to 100 AU. The inner edge of the molecular gas emission is consistent with the inner edge of the optically thick dust disk indicating that the inner hole is not simply a hole in the dust opacity but is likely cleared of gas as well. The rotational temperature of the CO is {approx}1000 K-much hotter than the {approx}200 K CO in the otherwise similar transitional disk surrounding HD 141569. The origin of this discrepancy is likely linked to the brighter polycyclic aromatic hydrocarbon emission observed toward HD 100546. We use the excitation of the CO to constrain the geometry of the inner disk and comment on the evolutionary state of the system.

• OSTI ID: 21333869
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 702; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
DUSTS
FLUORESCENCE
MATTER
POLYCYCLIC AROMATIC HYDROCARBONS
PROTOPLANETS
SIMULATION
STARS