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Infrared photometry and mass loss rates for OBA supergiants and Of stars

BARLOW, MJ; COHEN, M; (1977) Infrared photometry and mass loss rates for OBA supergiants and Of stars. Astrophysical Journal , 213 pp. 737-755. 10.1086/155204. Green open access

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Abstract

We present infrared observations of 34 OBA supergiants and 10 Of and Oe stars. Excess free- free emission is detectable at 10 m but not at shorter wavelengths for the supergiants. From our 2.2 and 3.6 t m photometry of the supergiants, in conjunction with existing UBV data, we derive an invariant ratio of total to selective extinction, R = 3.10 + 0.03. Using published radio and infrared data, we derive the velocity law for the mass loss outflow from P Cygni, and we apply this velocity law to the measured 10 m excess fluxes from our sample of supergiants in order to derive mass loss rates. Our preliminary survey of Of and Oe stars shows excess free-free emission to be common at 3.6 m and sometimes detectable at 2.2 t m. Using our 2.2-10 m data, we derive mass loss rates for several 0 stars. Our results are consistent with radiation pressure being the driving mechanism for mass loss from OBA supergiants and Of stars. Subject headings: interstellar: matter - stars: circumstellar shells - stars: early-type - stars: mass loss - stars: Of-type - stars: supergiants

Type: Article
Title: Infrared photometry and mass loss rates for OBA supergiants and Of stars
Open access status: An open access version is available from UCL Discovery
DOI: 10.1086/155204
Publisher version: https://doi.org/10.1086/155204
Language: English
Additional information: This version is the version of record. For information on re-use, please refer to the publisher’s terms and conditions.
Keywords: Infrared Astronomy; Infrared Photometry; O Stars; Stellar Mass Ejection; Stellar Spectrophotometry; Supergiant Stars; A Stars; B Stars; Black Body Radiation; Early Stars; Interstellar Extinction; Mass Flow; Ubv Spectra; Astrophysics
UCL classification: UCL
UCL > Provost and Vice Provost Offices
UCL > Provost and Vice Provost Offices > UCL BEAMS
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences
UCL > Provost and Vice Provost Offices > UCL BEAMS > Faculty of Maths and Physical Sciences > Dept of Physics and Astronomy
URI: https://discovery.ucl.ac.uk/id/eprint/10096231
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