2001A&A...376..898M


C.D.S. - SIMBAD4 rel 1.7 - 2021.03.04CET20:59:40

2001A&A...376..898M - Astronomy and Astrophysics, volume 376, 898-906 (2001/9-4)

P Cygni in a short S Doradus phase. Spectroscopic and photometric evidences.

MARKOVA N., MORRISON N., KOLKA I. and MARKOV H.

Abstract (from CDS):

We studied the long-term spectral and photometric behaviour of P Cygni over the 13.8 year interval from March 1985 to January 1999. The UBV photometry reveals a slow (∼7.4-year), low-amplitude (∼0.1mag) variation in V in which the star becomes redder when it brightens and vice versa. It underwent a possible maximum in the winter of 1985 (between JD 2446000 and JD 2446200), a minimum in the winter of 1989 (between JD 2447500 and JD 2447700), a maximum in the fall of 1992 (between JD 2448800 and JD 2449000), and a minimum in the spring of 1996 (between JD 2450100 and JD 2450300) The properties of this variation are typical for weak-active S Dor variables in ``short S Dor phase'' (van Genderen, 2001A&A...366..508V). Simultaneous spectroscopic observations show changes in the Hα equivalent width (corrected for the effect of the changing continuum) in positive correlation with the 7.4-year photometric oscillation in the V-band brightness. This result is interpreted as an indication that in P Cygni an increase in the stellar brightness, during the 7.4-year SD phase, is likely accompanied by an increase in the mass-loss rate. In this behaviour P Cygni is similar to S Dor and R71. From simple considerations, it is concluded that the 7.4-year SD cycle is probably a combination of an increasing radius/decreasing effective temperature and an expanding pseudo-photosphere.

Abstract Copyright:

Journal keyword(s): stars: oscillations - stars: mass loss - stars: individual: P Cygni

Simbad objects: 5

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Number of rows : 5

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 M 31 G 00 42 44.330 +41 16 07.50 4.86 4.36 3.44     ~ 11212 1
2 M 33 GiG 01 33 50.904 +30 39 35.79 6.17 6.27 5.72     ~ 5250 1
3 HD 269006 s*b 05 02 07.3944119328 -71 20 13.118657760 9.93 10.60 10.55 10.43 10.38 LBV 235 0
4 V* S Dor sg* 05 18 14.3572490675 -69 15 01.148131817 9.08 10.39 10.25 9.74 9.14 A5Iaeq 352 0
5 * P Cyg s*b 20 17 47.2020844 +38 01 58.552724 4.66 5.24 4.82 4.28 4.02 B1-2Ia-0ep 1140 1

    Equat.    Gal    SGal    Ecl

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