2000A&A...362.1020F


Query : 2000A&A...362.1020F

2000A&A...362.1020F - Astronomy and Astrophysics, volume 362, 1020-1040 (2000/10-3)

Stellar and circumstellar activity in the Be star EW Lacertae from the 1993 multi-site campaign.

FLOQUET M., HUBERT A.M., HIRATA R., McDAVID D., ZOREC J., GIES D., HAHULA M., JANOT-PACHECO E., KAMBE E., LEISTER N.V., STEFL S., TARASOV A. and NEINER C.

Abstract (from CDS):

A multi-site, multi-technique campaign on the Be star EWLac was held for about 9 days in August-September 1993. We present results of the analysis of visual, high S/N spectroscopic data (HeI 6678Å and Hα). Search for short-term variability was carried out on HeI 6678 (line profiles, radial velocity (RV), equivalent width (EW), full width at half-maximum (FWHM) on the absorption part of the line profile and on violet (V) and red (R) emission peaks) and on Hα emission line (line profiles, EW, V, R and V/R ratio). The presence of multi-periodicity is confirmed and we detected the frequencies found in 1989 by Floquet et al. (1992A&A...264..177F) during a 8-day mono-site campaign. Possible non-radial pulsation solutions for the main frequencies detected are l≃2-3, |m|≃2-3. We found evidence on the HeI 6678 line of episodic matter outflows through the presence of relatively broad, variable absorption line-profile variations. At least one sharp absorption feature was also observed slowly crossing the stellar disc. It is attributed to a blob of matter temporarily orbiting the star. A brief account is given of broad-band polarimetric observations, performed over 6 nights. A correlation is found between the variation in intrinsic polarization level in the B-band and HeI 6678Å strength. Finally, we present a simple model that reproduces rather well the additional ``pseudo-photosphere" contribution in 1993 as opposed to 1989.

Abstract Copyright:

Journal keyword(s): stars: circumstellar matter - stars: emission-line, Be - stars: oscillations - stars: individual: EW Lac - stars: variables: general

Simbad objects: 8

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Number of rows : 8
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 * 56 Eri Be* 04 44 05.3207274312 -08 30 12.852684720 4.97 5.75 5.81 5.72 5.74 B2(V)nne 176 0
2 HD 44458 Be* 06 21 24.7165403448 -11 46 23.666159604 4.74 5.56 5.55 5.38 5.34 B1.5IVe 152 0
3 * 27 CMa Be* 07 14 15.2119175 -26 21 09.031206 3.76 4.45 4.65 4.64 4.73 B4Ve_sh 222 0
4 * ome CMa Be* 07 14 48.6538664 -26 46 21.609714 2.90 3.64 3.82 3.80 3.90 B2.5Ve 340 0
5 * mu. Cen Be* 13 49 36.9886294 -42 28 25.429594 2.37 3.27 3.43 3.41 3.50 B2Vnpe 422 0
6 * 48 Lib Be* 15 58 11.3682502453 -14 16 45.681109093 4.61 4.77 4.87 4.91 4.96 B5IIIp_sh 432 0
7 * omi Aqr Be* 22 03 18.8440292 -02 09 19.306758 4.22 4.64 4.69 4.70 4.74 B5V 260 0
8 HD 217050 Be* 22 57 04.5020619144 +48 41 02.645623680 4.81 5.34 5.43     B4IIIpe 321 1

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2022.06.29-06:35:07

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