Photometric variability and spectrum of the post-AGB candidate IRAS 19200+3457 |
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Authors: | V. P. Arkhipova N. P. Ikonnikova R. I. Noskova G. V. Komissarova V. F. Esipov |
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Affiliation: | (1) Sternberg Astronomical Institute, Universitetskii pr. 13, Moscow, 119992, Russia |
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Abstract: | We present our photoelectric and spectroscopic observations of the early B supergiant with an IR excess IRAS 19200+3457, a poorly known post-AGB candidate. The star has been found to be photometrically variable. We observed rapid irregular brightness variations with amplitudes up to (Delta V = 0mathop .limits^m 4, Delta B = 0mathop .limits^m 4), and (Delta U = 0mathop .limits^m 5). IRAS 19200+3457 and three other hot post-AGB stars—V886 Her, V1853 Cyg, and LSIV—12°111—exhibit a similar variability pattern. Our low-resolution spectroscopic observations in the period 2001–2003 show that the spectrum of IRAS 19200+3457 represents an early B star with hydrogen emission lines originating from a circumstellar gaseous envelope. The HeI λ5876 Å, λ6678 Å, λ7065 Å, and OI λ7774 Å lines are in absorption. The hydrogen and, probably, HeI lines proved to be variable. Our observations confirm the conclusion that IRAS 19200+3457 belongs to the class of intermediate-mass protoplanetary objects. |
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Keywords: | post-AGB supergiants photometry and spectroscopy |
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