2002A&A...385..619V


Query : 2002A&A...385..619V

2002A&A...385..619V - Astronomy and Astrophysics, volume 385, 619-631 (2002/4-2)

The enigmatic WR46: A binary or a pulsator in disguise. III. Interpretation.

VEEN P.M., VAN GENDEREN A.M. and VAN DER HUCHT K.A.

Abstract (from CDS):

Photometric and spectroscopic monitoring campaigns of WR46 (WN3p), as presented in Veen et al. (2002a,b; hereafter Papers I and II, respectively), yield the following results. The light- and colour variations reveal a dominant single-wave period of Psw89=0.1412d in 1989, and Psw91=0.1363d in 1991. Because of a small difference in the minima, this periodicity may be a double-wave phenomenon (Pdw). The line fluxes vary in concert with the magnitudes. The significant difference of the periods can be either due to the occurence of two distinct periods, or due to a gradual change of the periodicity. A gradual brightening of the system of 0.12mag appeared to accompany the period change. In addition, the light variations in 1989 show strong evidence for an additional period Px=0.2304d. Generally, the radial velocities show a cyclic variability on a time scale of the photometric double-wave. However, often they do not vary at all. The observed variability confirms the Population I WR nature of the light source, as noted independently by Marchenko et al. (2000AJ....120.2101M). In the present paper, we first show how the photometric double-wave variability can be interpreted as a rotating ellipsoidal density distribution in the stellar wind. Subsequently, we discuss what mechanisms could drive such a configuration. First, stellar rotation of a single star is discarded as a likely cause. Second, the obvious interpretation of the double-wave photometry, i.e., a close binary system, is investigated. However unlikely, we discuss how the observed period change might be reconciled within a model of a strongly interacting binary. Third, an interpretation of a non-radial multi-mode pulsator is investigated. The observed period change and the multi-frequency behaviour do support this interpretation. We propose that the pulsational mode l=1 and |m|=1 may mimic a ``binary'' light- and radial-velocity curve. However, the phasing of the radial velocity and the light curve may be inconsistent. The possibility l=2 and |m|=0 is also discussed. Finally, we suggest how the enigma of the variability of WR46 may be solved.

Abstract Copyright:

Journal keyword(s): stars: Wolf-Rayet - stars: individual: WR 46 - stars: binaries: close - stars: variables: general - stars: oscillations

Simbad objects: 11

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Number of rows : 11
N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2022
#notes
1 HD 5980 WR* 00 59 26.5838833944 -72 09 53.927337312   11.13 11.31   11.029 WN4+O7I: 375 1
2 HD 50896 WR* 06 54 13.0439608392 -23 55 42.023319852 5.74 6.63 6.91 7.74   WN4b 756 0
3 V* V779 Cen HXB 11 21 15.0920532528 -60 37 25.630264596   14.4 12.27     O9III/Veq 1035 0
4 V* SV Cen EB* 11 47 57.2198787264 -60 33 57.760436736 7.98 9.71 9.70 9.46 8.810 B1/3 142 0
5 HD 104994 WR* 12 05 18.7204232424 -62 03 10.140656832 9.95 10.94 10.93 11.03   WN3p-w 161 0
6 HD 134877 WR* 15 14 57.7186057272 -59 50 30.215432688 12.13 12.19 11.34 11.08   WN8(h) 102 0
7 HD 160529 sg* 17 41 59.0261939376 -33 30 13.704456780 8.17 7.87 6.66 5.50 4.51 A2Ia 192 1
8 HD 164270 WR* 18 01 43.1453595672 -32 42 55.161329040 8.52 8.97 8.74 9.51   WC9d+? 221 0
9 WR 109 WR* 18 07 50.8972634088 -35 10 25.118702292           WN3 54 0
10 HD 191765 WR* 20 10 14.1928045152 +36 10 35.070683376 7.64 8.08 8.08     WN6-s 434 0
11 V* V1521 Cyg HXB 20 32 25.78 +40 57 27.9           WN4/5-6/7 1873 2

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2022.10.01-09:56:44

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