Photometric and Spectroscopic Observations of Infrared Stars

Abstract

view Abstract Citations (106) References (23) Co-Reads Similar Papers Volume Content Graphics Metrics Export Citation NASA/ADS Photometric and Spectroscopic Observations of Infrared Stars Low, F. J. ; Johnson, H. L. ; Kleinmann, D. E. ; Latham, A. S. ; Geisel, S. L. Abstract Photometric observations from U to Q (0.36 to 22 ) are reported for six stars that are bright in the infrared: Becklin's Object, HD 45677, R Mon, T Tau, NML Cyg, and VY CMa. Spectroscopic observations from 2500 to 7000 have been obtained for three of these objects: NML Cyg, VY CMa, and HD 45677. These data suggest that all six systems contain protostars at various stages of evolution ranging in bolometric luminosity from 15 L0 to 30000 Lo, although gravitational collapse appears to be an inadequate source of energy. In every case, most of the infrared radiation appears to be produced by thermal reradiation from thin shells of circumstellar particles between 500 and 900 K. By using spectral data to determine the temperatures of the central stars, extinction curves were derived for two of these circumstellar shells. The resulting distribution of particle sizes is consistent with the long-wavelength behavior of the emission, which shows definite particle-size effects. By assuming spherical symmetry, the linear radii calculated for the shells range from 1.5 to 100 a.u.; the mass of dust was estimated to be 4 M for VY CMa and 10- Me for T Tau, which are, respectively, the heaviest and the lightest of these objects. Publication: The Astrophysical Journal Pub Date: May 1970 DOI: 10.1086/150452 Bibcode: 1970ApJ...160..531L full text sources ADS | data products SIMBAD (16)