Subdwarf B–Stars and Binarity

Theissen, A.; Boer, K. S. de; Moehler, S.; Heber, U.

doi:10.1007/978-94-011-2020-3_13

Cited by 10 publications

(20 citation statements)

References 12 publications

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“…We have not used the results of Moehler et al (1990b) or Theissen et al (1993) in the calibrations, as colors were used in these analyses to determine the effective temperatures, and the effective temperature versus color calibration used (Lester et al 1986) is not valid for O and B subdwarfs . We also did not use the results of Saffer et al (1994) in the calibrations because they are based on spectra of a much lower (and variable) resolution and because the analyses did not account for metallic line blanketing.…”

Section: Calibrationsmentioning

confidence: 99%

An MK-like system of spectral classification for hot subdwarfs

Drilling

Jeffery

Heber

et al. 2013

A&A

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An MK (Morgan-Keenan)-like system of spectral classification for hot subdwarfs is presented. We find that a three-dimensional spectral type, consisting of a "spectral" class, a "luminosity" class, and a "helium" class, is necessary to classify the sdO (subdwarf O) and sdB (subdwarf B) stars. In addition, the helium-strong stars appear to form two parallel spectral sequences: one showing strong lines of CII, CIII, or CIV, and the other with these same lines weak or absent. We also give a preliminary calibration of the new spectral types in terms of effective temperature, surface gravity, and surface helium-to-hydrogen abundance ratio, and show the relation between the new spectral types and the natural groups defined by the Palomar-Green (PG) survey.

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Section: Calibrationsmentioning

confidence: 99%

An MK-like system of spectral classification for hot subdwarfs

Drilling

Jeffery

Heber

et al. 2013

A&A

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“…13 and Tables 11 and 12. For PG 1701+359 we get a much smaller distance with Eq. (6) than the one listed in Theissen et al (1993). We think that the original distance is the erroneous one as the theoretical magnitude derived from it differs by 2 m .…”

Section: Distances To Hot Stars In the Fieldmentioning

confidence: 83%

“…Theissen et al (1993) See Fig. 13 and Tables 11 and 12. For PG 1701+359 we get a much smaller distance with Eq.…”

Section: Distances To Hot Stars In the Fieldmentioning

confidence: 99%

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Hot horizontal branch stars in NGC 288 – effects of diffusion and stratification on their atmospheric parameters(Corrigendum)

Moehler

Leblanc

Khalack

et al. 2017

A&A

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We found that the script to determine the masses of the stars contains two errors. This script and a related one have been used to determine masses of globular cluster stars and distances to field stars in 12 papers published between 1990 and 2014. While the numerical values need to be revised none of the conclusions are affected. We provide the updated numerical values and figures for all 12 publications here. In addition we describe the effects on those refereed publications that used the distances to the field stars.

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“…Saffer et al (1994) did not recognize the composite nature of PG 0749+658 and PG 2135+045, and it is not clear how they modelled the spectrum of PG 2110+127. When deriving the sdB parameters, Theissen et al (1993Theissen et al ( , 1995 corrected for the continuum light of the cool companions, but not the (weaker) Balmer lines from the cool stars. Therefore these results may not be fully reliable.…”

Section: Composite Spectramentioning

confidence: 99%

Physical Parameters for Subdwarf B Stars with Composite Spectra

Cuadrado¹,

Jeffery²

2003

White Dwarfs

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Abstract. New intermediate-resolution spectra have been obtained for a number of subdwarf B stars having both single and composite spectra. Physical parameters have been determined for the sdB stars and, in compositespectrum systems, their cool companions. For these binaries, we have developed a method which uses the blueoptical spectrum to determine the effective temperatures of both stars, the surface gravity of the hot stars and the radius ratio of the system. The surface gravity of the cool star is measured using the infrared calcium triplet. The surface gravities of these cool companions identify them as main-sequence stars with masses in the range 0.8-1.2 M , confirming a previous energy distribution analysis. There is also evidence that the composite-spectrum sdBs are more helium-poor than single-spectrum sdBs.

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Subdwarf B–Stars and Binarity

Cited by 10 publications

References 12 publications

An MK-like system of spectral classification for hot subdwarfs

An MK-like system of spectral classification for hot subdwarfs

Hot horizontal branch stars in NGC 288 – effects of diffusion and stratification on their atmospheric parameters(Corrigendum)

Physical Parameters for Subdwarf B Stars with Composite Spectra

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