THE EVOLUTION OF CIRCUMSTELLAR DISKS SURROUNDING INTERMEDIATE-MASS STARS: IC 1805

Journal Article · Sat Jan 01 04:00:00 EST 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/726/1/19· OSTI ID:21567745

Wolff, S C; Strom, S E ^[1]

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1. NOAO, 950 North Cherry Avenue, Tucson, AZ (United States)

We report the results of a study of the intermediate- and high-mass stars in the young, rich star-forming complex IC 1805, based on a combination of optical, near-infrared, and mid-infrared photometry, and classification spectra. These data provide the basis for characterizing the masses and ages for stars more massive than {approx}2 M{sub sun} and enable a study of the frequency and character of circumstellar disks associated with intermediate- and high-mass stars. Optically thick accretion disks among stars with masses 2 < M/M{sub sun} < 4 are rare ({approx}2% of members) and absent among more massive stars. A larger fraction ({approx}10%) of stars with masses 2 < M/M{sub sun} < 4 appear to be surrounded by disks that have evolved from the initial optically thick accretion phase. We identify four classes of such disks. These classes are based on spectral energy distributions (SEDs) of excess emission above photospheric levels: disks that are (1) optically thin based on the magnitude of the observed excess emission from 2 to 24 {mu}m, (2) optically thin in their inner regions (r < 20 AU) and optically thick in their outer regions, (3) exhibit empty inner regions (r < 10 AU) and optically thin emission in their outer regions, and (4) exhibit empty inner regions and optically thick outer regions. We discuss, and assess the merits and liabilities of, proposed explanations for disks exhibiting these SED types and suggest additional observations that would test these proposals.

• OSTI ID: 21567745
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 726; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
ACCRETION DISKS
EMISSION
ENERGY SPECTRA
EVOLUTION
MASS
SPECTRA
STAR EVOLUTION
STARS