Radial Velocity Variations of the Be Shell Star V923 AQL /HD 183556/ in the Past Sixty Years

Koubský, P.; Gulliver, A. F.; Harmanec, P.; Ballereau, D.; Chauville, J.; Gráf, Tomáš; Horn, J.; Iliev, L.; Lyons, R. W.

doi:10.1007/978-94-009-2413-0_67

Cited by 9 publications

(28 citation statements)

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“…It is also one of the first stars for which periodic rapid light variations were found (a period of 0.8518 day and a variable amplitude up to 0. m 1, Lynds 1960). V923 Aql exhibits variations in radial velocity and V/R ratio of the double emission peaks on a time scale of about six years (Koubský et al 1989). Small photometric variations on several time scales were reported by Percy et al (1988b).…”

Section: Hd 183656 (V923 Aql)mentioning

confidence: 75%

UBV photometry of Be stars at Hvar: 1972–1990

Pavlovski¹,

Harmanec

Božić³

et al. 1997

Astron. Astrophys. Suppl. Ser.

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Abstract. A summary of results of the systematic UBV photoelectric monitoring of bright northern Be stars carried out at the Hvar Observatory between 1972 and 1990 is presented. Altogether, 76 Be stars of all luminosity classes were observed and 13 848 UBV measurements secured. Simultaneously, 9 648 UBV measurements of 48 check stars (most of them of early spectral types) were obtained. A careful transformation of all observations into the standard Johnson system allowed detection and monitoring of even very mild long-term light and colour variations of these objects. Almost all early-type Be stars in the sample turned out to be variable. For several stars phase-locked light variations related to their binary nature were established. Sudden brightenings, on a time scale of a few days, were detected for o Cas and QR Vul.

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Section: Hd 183656 (V923 Aql)mentioning

confidence: 75%

UBV photometry of Be stars at Hvar: 1972–1990

Pavlovski¹,

Harmanec

Božić³

et al. 1997

Astron. Astrophys. Suppl. Ser.

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“…HD 183 656 is a spectroscopic binary shell star (SB1) with an orbital period of 214.75 d (Koubsky et al 1989). This star was found to be variable by Lynds (1960) −1 , but we cannot confirm this frequency due to the few points of the sample.…”

Section: A211 Hd 183 656mentioning

confidence: 99%

A photometric study of Be stars located in the seismology fields of COROT

Gutiérrez‐Soto

Fabregat

Suso³

et al. 2007

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Context. In preparation for the COROT mission, an exhaustive photometric study of Be stars located in the seismology fields of the mission has been performed. The very precise and long-time-spanned photometric observations gathered by the COROT satellite will give important clues on the origin of the Be phenomenon. Aims. The aim of this work is to find short-period variable Be stars located in the seismology fields of COROT, and to study and characterise their pulsational properties. Methods. Light curves obtained at the Observatorio de Sierra Nevada, together with data from Hipparcos and ASAS-3 for a total of 84 Be stars, were analysed in order to search for short-term variations. We applied standard Fourier techniques and non-linear least-square fitting to the time series. Results. We found 7 multiperiodic, 21 mono-periodic and 26 non-variable Be stars. Short-term variability was detected in 74% of early-type Be stars and in 31% of mid-to late-type Be stars. We show that non-radial pulsations are more frequent among Be stars than in slow-rotating B stars of the same spectral range.

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“…A rapidly variable shell star. D is correlated with the V/R variations (the V/R and radial velocity curves are given in Koubsky et al 1989). D is at maximum when the RV is at maximum.…”

Section: Brief Remarks On the Remaining Be Starsmentioning

confidence: 99%

Long-term visual spectrophotometric behaviour of Be stars

Moujtahid

Zorec²,

Hubert

et al. 1998

Astron. Astrophys. Suppl. Ser.

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Abstract. The long-term spectrophotometric variations of 49 Be stars are studied using the U and V magnitudes of the UBV system, the total Balmer discontinuity D and the visible gradient Φ rb . BCD spectrophotometric and photometric data in five different photometric systems, obtained in most cases since 1950 and reduced to the BCD system, were used. The (U, D), (V, D), (Φ rb , D) and (Φ rb , V ) correlations obtained differ from star to star and they can be single or double-valued. They differ clearly for Be phases or Be-shell phases. Be stars with small V sin i showing the "spectrophotometric shell behaviour": D > D * , were found. This finding implies either that strongly flattened models of circumstellar envelopes are in doubt for these stars, or that not all Be stars are rapid rotators. Comparison of observed variations with those predicted for model Be stars with spherical circumstellar envelopes of variable densities and dimensions implies that spectrophotometric patterns of Be phases are due to circumstellar envelopes in low opacity regimes, while those of spectrophotometric shell phases are due to circumstellar envelopes in high opacity regimes. In a given star, the envelope regions responsible for the observed variations of D and Φ rb in spectrophotometric shell phases seem to be smaller and denser than those producing the observed variations of these parameters in spectrophotometric Be phases. The high positive RV found in strong shell phases might favor the formation of compact circumstellar layers near the star.

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Radial Velocity Variations of the Be Shell Star V923 AQL /HD 183556/ in the Past Sixty Years

Cited by 9 publications

References 0 publications

UBV photometry of Be stars at Hvar: 1972–1990

UBV photometry of Be stars at Hvar: 1972–1990

A photometric study of Be stars located in the seismology fields of COROT

Long-term visual spectrophotometric behaviour of Be stars

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