Circumstellar envelope of IRC+10216

Journal Article · Mon Aug 01 04:00:00 EDT 1977 · Astrophys. J.; (United States)

DOI:https://doi.org/10.1086/155413· OSTI ID:7214329

Kwan, J; Hill, F

The circumstellar envelope of IRC+10216, a late-type carbon star, is modeled, and theoretical calculations of CO, /sup 13/CO, HCN, and H/sup 13/CN emission are compared with observations. A steady mass loss from the star is assumed. The gas temperature in the flow is determined from considerations of the cooling due to free expansion and molecular emission, and the heating due to gas-dust collisions. The CO and /sup 13/CO J=1..-->..0 intensities are found to be insensitive to vibrational excitation by infrared photons. The HCN, H/sup 13/CN J=1..-->..0 lines, on the other hand, depend primarily on vibrational excitation. The mass loss rate, deduced from the CO observations, is remarkably close to the limiting rate, for a flow driven by radiation pressure, of approx.L/(cv/sub t/), where L is the luminosity and v/sub t/ is the therminal velocity of the expanding gas. Assuming a distance of 200 pc to IRC+10216, the deduced mass loss rate is 2.10/sup -5/ M/sub sun/yr/sup -1/ and the (CO)/(H/sub 2/) abundance ratio about 8x10/sup -4/, both uncertain to a factor of 2. Comparing the CO with the /sup 13/CO emission, a (CO)/(/sup 13/CO) isotope ratio of 35 +- 7 is obtained.

• Research Organization: State University of New York, Stony Brook
• OSTI ID: 7214329
• Journal Information: Astrophys. J.; (United States), Journal Name: Astrophys. J.; (United States) Vol. 215:3; ISSN ASJOA
• Country of Publication: United States
• Language: English

Related Subjects

640102* -- Astrophysics & Cosmology-- Stars & Quasi-Stellar
Radio & X-Ray Sources
71 CLASSICAL AND QUANTUM MECHANICS
GENERAL PHYSICS
ABUNDANCE
CARBON STARS
CHEMICAL COMPOSITION
COSMIC DUST
COSMIC GASES
DUSTS
ELECTROMAGNETIC RADIATION
ENERGY-LEVEL TRANSITIONS
FLUIDS
GASES
INFRARED RADIATION
INTERSTELLAR GRAINS
ISOTOPE RATIO
MASS TRANSFER
MATHEMATICAL MODELS
PARTICLES
RADIATIONS
STAR MODELS
STARS