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Spectral Variability of the Peculiar A-Type Supergiant 3 Pup

UNCG Author/Contributor (non-UNCG co-authors, if there are any, appear on document)
Anatoly S. Miroshnichenko, Associate Professor (Creator)
The University of North Carolina at Greensboro (UNCG )
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Abstract: Optical spectra taken in 1997–2008 are used to analyze the spectral peculiarities and velocity field in the atmosphere of the peculiar supergiant 3 Pup. The profiles of strong Fe II lines and of the lines of other iron-group ions have a specific shape: the wings are raised by emissions, whereas the core is sharpened by a depression. The latter feature becomes more pronounced with the increasing line strength, and the increasing wavelength. Line profiles are variable: the magnitude and sign of the absorption asymmetry, and the blue-to-red emission intensity ratios vary from one spectrum to another. The temporal Vr variations are minimal for the forbidden emissions and sharp shell cores of the absorption features of Fe II(42), and other strong lines of iron-group ions. The average velocity for the above lines can be adopted as the systemic velocity: Vsys = 28.5 ± 0.5 km/s. The weakest photospheric absorptions and photospheric Mg II, Si II absorptions exhibit well-defined day-to-day velocity variations of up to 7 km/s. Quantitative spectral classification yields the spectral type of A2.7±0.3 Ib. The equivalent widths and profiles of Hd and H?, and the equivalent width of the OI7774 Å triplet yield an absolute magnitude estimate of Mv = -5.5m ± 0.3m, implying the heliocentric distance of 0.7 kpc.

Additional Information

Astrophysical Bulletin
Language: English
Date: 2010
stars, variable and peculiar, astrophysics, astronomy