Be stars in open clusters. 
I. <i>uvby</i>
         $ ^{\bf \beta}$ photometry

Fabregat, J.; Torrejón, J. M.; Reig, P.; Bernabeu, Guillermo; Busquets, J.; Marco, A.; Reglero, V.

doi:10.1051/aas:1996244

Cited by 18 publications

(24 citation statements)

References 31 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…I present in Figure 3 two examples of Ha profiles with obvious variability of its emission with orbital phase. Fabregat et al (1996) determined the physical characteristics of the star and found that it is possible to conclude that neither component of the pair reaches the Terminal Age Main Sequence (TAMS). Nevertheless, BD56° 578 is still too poorly studied to make any final conclusion on its evolutional status.…”

Section: Be Stars In Double Systems With Both Components On the Main mentioning

confidence: 99%

Be Stars in Roche-Lobe Interacting Binaries

Tarasov

2000

International Astronomical Union Colloquium

View full text Add to dashboard Cite

Abstract. Different types of massive interacting binaries with Be components are discussed. Due to mass exchange, Be stars in these systems have some peculiar characteristics. Often it is even difficult to find traces of the Be star and/or mass-losing star in the optical region of the spectrum. Using the value of the orbital period as a primary parameter, it is possible to divide all massive interacting binaries into two large groups: short-period or classical Algols and long-period binaries. The last group includes a number of very active mass transfer systems named as W Serpentis. There is also a small group of double systems whose stars do not fill their Roche lobes but have emission lines in the spectrum. Properties of their spectral variability are discussed. Analysis of each group lets us find different behaviours in mass exchange that depend on the size of their Roche lobes.

show abstract

Section: Be Stars In Double Systems With Both Components On the Main mentioning

confidence: 99%

Be Stars in Roche-Lobe Interacting Binaries

Tarasov

2000

International Astronomical Union Colloquium

View full text Add to dashboard Cite

show abstract

“…We note that the variable component of the BD enters the Strömgren photometric filter u (or U filter of the UBV system), which can then produce photometric indices that do not reflect the genuine photospheric BD of the star and leads to wrong spectral classifications, as well as to bad fundamental parameter determinations (Divan & Zorec 1982). The effects of circumstellar emission in the bands and indices of the Strömgren system have been studied in detail by Fabregat & Reglero (1990) and Fabregat et al (1996). They clearly show that circumstellar emission or absorption significantly modify the values of the (b − y) and c 1 indices, which cannot be considered as effective temperature indicators without applying the adequate corrections.…”

Section: Discussionmentioning

confidence: 86%

Study of a sample of faint Be stars in the exofield of CoRoT

Semaan

Hubert

Zorec

et al. 2013

A&A

Self Cite

View full text Add to dashboard Cite

Context. Be stars are probably the most rapid rotators among stars in the main sequence (MS) and, as such, are excellent candidates to study the incidence of the rotation on the characteristics of their non-radial pulsations, as well as on their internal structure. Pulsations are also thought to be possible mechanisms that help the mass ejection needed to build up the circumstellar disks of Be stars. Aims. The purpose of this paper is to identify a number of faint Be stars observed with the CoRoT satellite and to determine their fundamental parameters, which will enable us to study their pulsation properties as a function of the location in the HR diagram and to search for correlations with the light outbursts, which are possibly produced by discrete mass ejections. Methods. We identified those objects in the exofields of CoRoT presenting the Be phenomenon using Hα surveys, as well as automated methods based on pulsation properties that we finally confirmed with FLAMES/GIRAFFE and X-shooter spectroscopic observations at VLT/ESO, and with near-IR photometry. The spectra were 1) corrected for the veiling effect, 2) treated with the GIRFIT code to determine apparent fundamental parameters, and 3) corrected with the FASTROT code for effects induced by the rapid rotation. Results. A list of 41 Be star candidates were found from photometric and spectroscopic criteria. The spectral coverage useful for determining the fundamental parameters was obtained for only about half of them. We then spectroscopically identified 21 Be stars, two probable Be stars, and two B stars contaminated by the Sh 2-284 nebulosity. A short description of the spectral characteristics of each star is given. The fundamental parameters and, in particular, the rotation frequency ν r (cycles per day) were all corrected for rotational effects at rotation rates ranging from Ω/Ω c = 0.8 to 1.0. We have determined the positions of Be stars in the HR diagram and find two of them located beyond the MS phase. Conclusions. The well-determined fundamental parameters presented in this paper for a statistically reliable sample of Be stars will enable us in forthcoming papers to compare the properties of stars as pulsators either according to their location in different regions of the HR diagram or with those predicted from theory.

show abstract

“…The large absorption in the south-east part has been previously pointed out by Waelkens et al (1990) from photoelectric photometry in the Geneva system, but surprisingly has not been accounted for in recent CCD studies. On the other hand, the low reddening value in the western part was already noted by Fabregat et al (1996). They considered the Be stars Oo 146, 245 and 566 as probable nonmembers, due to their reddening values (E(b − y) = 0.313, 0.346 and 0.308 respectively), which are much lower than the cluster average reddening.…”

Section: Reddening Intrinsic Colours and Distancementioning

confidence: 87%

“…If we assume that (b − y) 0 is a good temperature indicator for all luminosity classes (see below), this implies that the The case is much the same as for classical Be stars. Be stars also have continuum emission or absorption of circumstellar origin at the Balmer discontinuity, and hence their c 0 indices are anomalous (Fabregat et al 1996, and references therein). For comparison, in Fig.…”

Section: Discussionmentioning

confidence: 99%

See 1 more Smart Citation

CCD $uvby\beta$ photometry of young open clusters

Capilla

Fabregat

2002

A&A

Self Cite

View full text Add to dashboard Cite

Abstract. We present CCD uvbyβ photometry for stars in the nuclei of the young double cluster h and χ Persei. We find that the reddening is highly variable through the h Per nucleus, increasing from west to east, with values ranging from E(b − y) = 0.328 ± 0.022 in the western part to E(b − y) = 0.465 ± 0.024 in the south-east. Towards χ Per the reddening is fairly constant, with E(b − y) = 0.398 ± 0.025. Both clusters share a common distance modulus of 11.7 ± 0.1 mag, and an age of log t = 7.10 ± 0.05 years.

show abstract

Be stars in open clusters. I. uvby $ ^{\bf \beta}$ photometry

Cited by 18 publications

References 31 publications

Be Stars in Roche-Lobe Interacting Binaries

Be Stars in Roche-Lobe Interacting Binaries

Study of a sample of faint Be stars in the exofield of CoRoT

CCD $uvby\beta$ photometry of young open clusters

Contact Info

Product

Resources

About