Ultraviolet and infrared monitoring of FG Sagittae during 1982-1989 - Evolutionary status

Journal Article · Thu Nov 01 04:00:00 EST 1990 · Astrophysical Journal; (USA)

DOI:https://doi.org/10.1086/169335· OSTI ID:6231625

Montesinos, B; Cassatella, A; Gonzalez-Riestra, R; Fernandez-Castro, T; Eiroa, C ^[1]

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1. Oxford Univ. (England) IUE Observatory, Madrid (Spain) CNR, Istituto di Astrofisica Spaziale, Frascati (Italy) ESTEC, Noordwijk (Netherlands) Madrid, Planetario (Spain) Observatorio Astronomico Nacional, Madrid (Spain)

Ultraviolet IUE spectra and infrared JHKL photometry of FG Sge obtained over the period 1982-1989 indicate that the cooling rate of the star observed until about 1980 seems to have stopped and that an increase of the effective temperature may have occurred, this being a significant change in the evolutionary path traced so far. The current spectral type of FG Sge is F6-7 I, as deduced from UV data. There is evidence of the existence of an envelope responsible for the infrared excesses observed at longer wavelengths. The short-term variation period is about 100-110 + or - 15 days, and it has remained stable since 1979, apart from small fluctuations of + or - 15 days. 50 refs.

• OSTI ID: 6231625
• Journal Information: Astrophysical Journal; (USA), Journal Name: Astrophysical Journal; (USA) Vol. 363; ISSN ASJOA; ISSN 0004-637X
• 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
COOLING
ELECTROMAGNETIC RADIATION
GIANT STARS
INFRARED RADIATION
LUMINOSITY
NEBULAE
OPTICAL PROPERTIES
PHOTOMETRY
PHYSICAL PROPERTIES
PLANETARY NEBULAE
RADIATIONS
SPECTRA
STAR EVOLUTION
STARS
SUPERGIANT STARS
ULTRAVIOLET RADIATION
ULTRAVIOLET SPECTRA
VARIABLE STARS