2002A&A...387..580H


C.D.S. - SIMBAD4 rel 1.7 - 2021.06.15CEST08:39:03

2002A&A...387..580H - Astronomy and Astrophysics, volume 387, 580-594 (2002/5-4)

Properties and nature of Be stars. XXI. The long-term and the orbital variations of V832 Cyg = 59 Cyg.

HARMANEC P., BOZIC H., PERCY J.R., YANG S., RUZDJAK D., SUDAR D., WOLF M., ILIEV L., HUANG L., BUIL C. and EENENS P.

Abstract (from CDS):

An analysis of numerous homogenized UBV photoelectric observations and red spectra of the Be star V832 Cyg from several observatories led to the following principal findings: 1. Pronounced long-term light and colour variations of V832 Cyg result from a combination of two effects: from the gradual formation of a new Be envelope, and from an asymmetry and a slow revolution of the envelope (or its one-armed oscillation). The colour variations associated with the envelope formation are characterized by a positive correlation between brightness and emission strength, typical for stars which are not seen roughly equator-on. 2. The V magnitude observations prewhitened for the long-term changes follow a sinusoidal orbital light curve with a small amplitude and a period of 28.1971d which is derived from observations spanning 43 years. This independently confirms a 12-year old suggestion that the star is a spectroscopic binary with a 29-d period. V832 Cyg thus becomes the fifth known Be star with cyclic long-term V/R variations, the duplicity of which has been proven, the four other cases being ζ Tau, V923 Aql, γ Cas and X Per. Therefore, the hypothesis that the long-term V/R variations may arise due to the attractive force of the binary companion at certain phases of the envelope formation is still worth considering as a viable alternative to the model of one-armed oscillation. 3. We have shown that the RV and V/R variations of the Hα and He I 6678 emission lines are all roughly in phase. In particular, the He I 6678 emission also moves with the Be primary which differs from what was found for another Be binary, φ Per. 4. We derived the orbital elements and found that in spite of the remaining uncertainties, the basic physical properties of the 28d.2 binary are well constrained. 5. The light minimum of the orbital light curve occurs at elongation when the Be star is approaching us and the object becomes bluest in (B-V) and reddest in (U-B) at the same time. This may indicate that a part of the optically thick regions of the envelope is eclipsed at these orbital phases.

Abstract Copyright:

Journal keyword(s): stars: emission-line, Be - stars: binaries: close - stars: binaries: spectroscopic - stars: fundamental parameters - stars: individual: V832 Cyg

VizieR on-line data: <Available at CDS (J/A+A/387/580): table3.dat table5.dat table6.dat table7.dat table567.tex>

Simbad objects: 14

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Number of rows : 14

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 * gam Cas Be* 00 56 42.5317 +60 43 00.265 1.18 2.29 2.39 2.32 2.40 B0.5IVpe 1154 2
2 * phi Per Be* 01 43 39.6379209 +50 41 19.432832 3.10 4.02 4.06 3.90 3.88 B1.5V:e-shell 541 0
3 V* X Per HXB 03 55 23.0778791365 +31 02 45.045745259 6.090 6.840 6.720     O9.5III 922 0
4 * zet Tau Be* 05 37 38.6854231 +21 08 33.158804 2.22 2.84 3.03 3.06 3.15 B1IVe_shell 702 0
5 * 4 Her Be* 15 55 30.5918031179 +42 33 58.287739693 5.23 5.64 5.75   5.82 B9pe 171 0
6 HD 183656 Be* 19 30 33.1219944607 +03 26 39.858289092 5.69 6.064 6.082     B7III 124 0
7 * 56 Cyg PM* 20 50 04.9312938076 +44 03 33.486215185       4.9   A6V 78 0
8 HD 199311 * 20 54 39.9306782966 +46 13 52.299405746   6.746 6.654     A2V 42 0
9 HD 199479 * 20 55 59.0074967347 +44 22 26.155407091   6.767 6.821     B9V 32 0
10 HD 199890 * 20 58 15.3068055377 +47 37 03.651216393 7.01 7.40 7.51     B5V 24 0
11 BD+46 3134 * 20 59 49.2797976077 +47 31 35.533218018   9.61 11.07 9.54   A3V 17 0
12 * f01 Cyg Be* 20 59 49.5516391039 +47 31 15.378902421 3.77 4.71 4.75 4.62 4.63 B1.5Vnne 471 0
13 HD 203245 * 21 19 28.7504084346 +49 30 37.062759934 5.11 5.61 5.74     B6V 66 0
14 * bet Cep bC* 21 28 39.5968513 +70 33 38.574681 2.05 3.01 3.23 3.33 3.55 B0.5IIIs 688 0

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2021.06.15-08:39:03

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