Four-color, Hbeta, and UBV photometry for bright B-type stars in the northern hemisphere

Crawford, D. L.; Barnes, J. V.; Golson, J. C.

doi:10.1086/111220

Cited by 49 publications

(37 citation statements)

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“…(1) Hauck & Mermilliod (1998); (2) Grønbech & Olsen (1976); (3) Crawford et al (1971); (4) Westin (1982); (5) Knude (1992); (6) Cameron (1966); (7) Olsen (1983); (8) Perry (1969); (9) Wolf & Kern (1983); (10) Kilkenny et al (1985); (11) Hauck & Mermilliod (1980); (12) Olsen (1993); (13) Gray & Olsen (1991); (14) Crawford et al (1971).…”

Section: Constraint On Strömgren Photometry and Weakly Ionised Emissiunclassified

Non-conservative evolution in Algols: where is the matter?

Deschamps

Braun

Jorissen

et al. 2015

A&A

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Context. There is indirect evidence of non-conservative evolutions in Algols. However, the systemic mass-loss rate is poorly constrained by observations and generally set as a free parameter in binary-star evolution simulations. Moreover, systemic mass loss may lead to observational signatures that still need to be found. Aims. Within the "hotspot" ejection mechanism, some of the material that is initially transferred from the companion star via an accretion stream is expelled from the system due to the radiative energy released on the gainer's surface by the impacting material. The objective of this paper is to retrieve observable quantities from this process and to compare them with observations. Methods. We investigate the impact of the outflowing gas and the possible presence of dust grains on the spectral energy distribution (SED). We used the 1D plasma code Cloudy and compared the results with the 3D Monte-Carlo radiative transfer code Skirt for dusty simulations. The circumbinary mass-distribution and binary parameters were computed with state-of-the-art binary calculations done with the Binstar evolution code. Results. The outflowing material reduces the continuum flux level of the stellar SED in the optical and UV. Because of the timedependence of this effect, it may help to distinguish between different ejection mechanisms. If present, dust leads to observable infrared excesses, even with low dust-to-gas ratios, and traces the cold material at large distances from the star. By searching for this dust emission in the WISE catalogue, we found a small number of Algols showing infrared excesses, among which the two rather surprising objects SX Aur and CZ Vel. We find that some binary B[e] stars show the same strong Balmer continuum as we predict with our models. However, direct evidence of systemic mass loss is probably not observable in genuine Algols, since these systems no longer eject mass through the hotspot mechanism. Furthermore, owing to its high velocity, the outflowing material dissipates in a few hundred years. If hot enough, the hotspot may produce highly ionised species, such as Si iv, and observable characteristics that are typical of W Ser systems. Conclusions. If present, systemic mass loss leads to clear observational imprints. These signatures are not to be found in genuine Algols but in the closely related β Lyraes, W Serpentis stars, double periodic variables, symbiotic Algols, and binary B[e] stars. We emphasise the need for further observations of such objects where systemic mass loss is most likely to occur.

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Section: Constraint On Strömgren Photometry and Weakly Ionised Emissiunclassified

Non-conservative evolution in Algols: where is the matter?

Deschamps

Braun

Jorissen

et al. 2015

A&A

View full text Add to dashboard Cite

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“…The zero point of the technique is checked by using UBV data for the field stars listed in Table 8. Those data are taken from Johnson et al (1966) whenever possible and from Crawford et al (1971) for the remaining stars. They are then used to calculate a formal zero-point correction to the Gutiérrez-Moreno algorithm.…”

Section: Appendix a Notes On The Newly Adopted Reddening Techniques Fmentioning

confidence: 99%

“…For stars listed in Table 8, these data are then subtracted from measured values of B − V to obtain values of E(B − V ). Once again, the B − V measurements are from Johnson et al (1966) and Crawford et al (1971). The spectral types are from the following sources: Cowley et al (1969), Houk (1982), Herbig & Spaulding (1955), , Lesh (1968), Morgan et al (1953), and Roman (1949).…”

Section: Appendix a Notes On The Newly Adopted Reddening Techniques Fmentioning

confidence: 99%

The Benchmark Cluster Reddening Project. Iv. A Statistical Test for Nonuniform Reddening in the Pleiades

Taylor

2008

The Astronomical Journal

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Using a protocol developed in previous papers in this series, the character of the Pleiades reddening is investigated. The protocol includes (1) analyses that yield results at the few-millimag level of precision and accuracy, (2) derivation of rigorous foundations for reddening values, (3) use of reddening techniques with limited metallicity sensitivity, (4) explicit zero-point control of input data, and (5) use of statistical analysis. It is found that in the eastern part of the Pleiades (as defined in a paper by Breger), E(B − V ) = 34 ± 11 mmag, with the quoted standard error depicting the amount of nonuniform reddening. In the western part of the Pleiades outside the "Southwest Nebula" (where E(B − V ) > 0.2 mag), the mean value of E(B − V ) = 57 ± 5.8 mmag, and the intrinsic rms scatter in E(B − V ) is 32 mmag. These results show that a widely adopted model in which E(B − V ) = 0.04 mag everywhere in the Pleiades outside the Southwest Nebula is not correct for any extended region in the Pleiades. They also show that the photometric properties of brown dwarfs in the western part of the Pleiades are not yet well established. In a collateral analysis, published high-dispersion values of [Fe/H] are used to derive mean metallicities for the Pleiades and Praesepe. The resulting values of [Fe/H] are −0.039 ± 0.014 dex and +0.057 ± 0.022 dex, respectively. When these results are combined with a mean high-dispersion metallicity for the Hyades, it is found that they are strongly inconsistent with a published explanation for the Pleiades distance modulus problem that is based specifically on photometric metallicities.

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“…Kaltcheva (1998) observed Carina OB1 and Carina OB2 using the half meter telescope at Sutherland site of the SAAO. The observations were calibrated to the standard system using standard stars from the lists of Cousins (1987), Perry et al (1987), Crawford et al (1971) and Olsen (1983). The reduction to the standard system was carried out by the procedure adopted at the SAAO.…”

Section: Abdel-rahman Et Almentioning

confidence: 99%

Statistical Gaussian Distribution Function as a Distance Indicator to Stellar Groups

Abdel-Rahman¹,

Issa²,

Sharaf³

et al. 2009

Journal of The Korean Astronomical Society

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In this paper, statistical distribution functions are developed for distance determination of stellar groups. This method depends on the assumption that absolute magnitudes and apparent magnitudes follow a Gaussian distribution function. Due to the limits of the integrands of the frequency function of apparent and absolute magnitudes, we introduce Case A, B, and C Gaussian distributions. The developed approaches have been implemented to determine distances to some clusters and stellar associations. The comparison with the distances derived by different authors reveals good agreement.

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Four-color, Hbeta, and UBV photometry for bright B-type stars in the northern hemisphere

Cited by 49 publications

References 0 publications

Non-conservative evolution in Algols: where is the matter?

Non-conservative evolution in Algols: where is the matter?

The Benchmark Cluster Reddening Project. Iv. A Statistical Test for Nonuniform Reddening in the Pleiades

Statistical Gaussian Distribution Function as a Distance Indicator to Stellar Groups

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