EVOLUTION OF THE DUST/GAS ENVIRONMENT AROUND HERBIG Ae/Be STARS

Journal Article · Fri Jun 10 00:00:00 EDT 2011 · Astrophysical Journal

DOI:https://doi.org/10.1088/0004-637X/734/1/22· OSTI ID:21576694

Tie, Liu; Huawei, Zhang; Yuefang, Wu ^[1]; Shengli, Qin; Miller, Martin ^[2]

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1. Department of Astronomy, Peking University, 100871 Beijing (China)
2. I. Physikalisches Institut, Universitaet zu Koeln, Zuelpicher Str. 77, 50937 Koeln (Germany)

Using the KOSMA 3 m telescope, 54 Herbig Ae/Be (HAe/Be) stars were surveyed in CO and {sup 13}CO emission lines. The properties of the stars and their circumstellar environments were studied by fitting spectral energy distributions (SEDs). The mean line width of {sup 13}CO (2-1) lines of this sample is 1.87 km s{sup -1}. The average column density of H{sub 2} is found to be 4.9 x 10{sup 21} cm{sup -2} for stars younger than 10{sup 6} yr, while this drops to 2.5 x 10{sup 21} cm{sup -2} for those older than 10{sup 6} yr. No significant difference is found among the SEDs of HAe and HBe stars of the same age. Infrared excess decreases with age, envelope masses and envelope accretion rates decease with age after 10{sup 5} yr, the average disk mass of the sample is 3.3 x 10{sup -2} M{sub sun}, the disk accretion rate decreases more slowly than the envelope accretion rate, and a strong correlation between the CO line intensity and the envelope mass is found.

• OSTI ID: 21576694
• Journal Information: Astrophysical Journal, Journal Name: Astrophysical Journal Journal Issue: 1 Vol. 734; ISSN ASJOAB; ISSN 0004-637X
• Country of Publication: United States
• Language: English

Related Subjects

79 ASTRONOMY AND ASTROPHYSICS
CARBON 13
CARBON COMPOUNDS
CARBON ISOTOPES
CARBON MONOXIDE
CARBON OXIDES
CHALCOGENIDES
CORRELATIONS
DENSITY
DUSTS
ELEMENTS
EMISSION
ENERGY SPECTRA
EVEN-ODD NUCLEI
EVOLUTION
HYDROGEN
ISOTOPES
LIGHT NUCLEI
LINE WIDTHS
MASS
NONMETALS
NUCLEI
OXIDES
OXYGEN COMPOUNDS
PHYSICAL PROPERTIES
SPECTRA
STABLE ISOTOPES
STAR EVOLUTION
STARS