Spectral analysis of multi mode pulsating sdB stars II. Feige 48, KPD 2109+4401 and PG 1219+534

Heber, U.; Reid, I. N.; Werner, K.

doi:10.48550/arxiv.astro-ph/0009159

Cited by 2 publications

(2 citation statements)

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“…Moreover, different atmospheric models could also lead to systematic errors in parameter determination. Heber et al (2000) determined atmospheric parameters for three pulsating sdB stars by using blanketed NLTE and LTE model atmospheres respectively. They found that there is no obvious difference in T eff determination between NLTE and LTE models, but NLTE log g is slightly lower than LTE ones by at least 0.05 dex (see Section 4.1 in their study for detailed discussion).…”

Section: Mass Calculation and Uncertainty Estimationmentioning

confidence: 99%

Hot Subdwarf Stars Identified in LAMOST DR8 with Single-lined and Composite Spectra

Lei

Németh

et al. 2023

ApJ

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A total of 222 hot subdwarf stars were identified with LAMOST DR8 spectra, among which 131 stars show composite spectra and have been decomposed, while 91 stars present single-lined spectra. Atmospheric parameters of all sample stars were obtained by fitting hydrogen (H) and helium (He) line profiles with synthetic spectra. Two long-period composite sdB binaries were newly discovered by combining our sample with the non-single-star data from Gaia DR3. One of the new systems presents the highest eccentricity (i.e., 0.5 ± 0.09) among known wide sdB binaries, which is beyond model predictions. A total of 15 composite sdB stars fall in the high-probability binary region of the RUWE−AEN plane and deserve priority follow-up observations to further study their binary nature. A distinct gap is clearly presented among temperatures of cool companions for our composite-spectrum sample, but we could not come to a conclusion as to whether this feature is connected to the formation history of hot subdwarf stars before their binary natures are confirmed.

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Section: Mass Calculation and Uncertainty Estimationmentioning

confidence: 99%

Hot Subdwarf Stars Identified in LAMOST DR8 with Single-lined and Composite Spectra

Lei

Németh

et al. 2023

ApJ

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show abstract

“…Moreover, different atmospheric models could also lead to systematic errors in parameter determination. Heber et al (2000) determined atmospheric parameters for three pulsating sdB stars by using blanketed NLTE and LTE model atmospheres, respectively. They found that there is no obvious difference in T eff determination between NLTE and LTE models, but NLTE g log is slightly lower than LTE ones by at least 0.05 dex (see Section 4.1 in their study for a detailed discussion).…”

Section: Mass Calculation and Uncertainty Estimationmentioning

confidence: 99%

Mass Distribution for Single-lined Hot Subdwarf Stars in LAMOST

Lei,

He,

Németh

et al. 2023

ApJ

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Masses for 664 single-lined hot subdwarf stars identified in LAMOST were calculated by comparing synthetic fluxes from spectral energy distribution with observed fluxes from a Virtual Observatory service. Three groups of hot subdwarf stars were selected from the whole sample according to their parallax precision to study the mass distributions. We found that He-poor sdB/sdOB stars present a wide mass distribution from 0.1 to 1.0 M ⊙ with a sharp mass peak at around 0.46 M ⊙, which is consistent with canonical binary model prediction. He-rich sdB/sdOB/sdO stars present a much flatter mass distribution than He-poor sdB/sdOB stars and with a mass peak at around 0.42 M ⊙. By comparing the observed mass distributions to the predictions of different formation scenarios, we concluded that the binary merger channel, including two helium white dwarfs (He-WDs) and He-WD + main-sequence mergers, cannot be the only main formation channel for He-rich hot subdwarfs, and other formation channels, such as the surviving companions from Type Ia supernovae, could also make impacts on producing this special population, especially for He-rich hot subdwarfs with masses less than 0.44 M ⊙. He-poor sdO stars also present a flatter mass distribution with an inconspicuous peak mass at 0.18 M ⊙. The similar mass– Δ RV max distribution between He-poor sdB/sdOB and sdO stars supports the scenario that He-poor sdO stars could be the subsequent evolution stage of He-poor sdB/sdOB stars.

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Spectral analysis of multi mode pulsating sdB stars II. Feige 48, KPD 2109+4401 and PG 1219+534

Cited by 2 publications

References 0 publications

Hot Subdwarf Stars Identified in LAMOST DR8 with Single-lined and Composite Spectra

Hot Subdwarf Stars Identified in LAMOST DR8 with Single-lined and Composite Spectra

Mass Distribution for Single-lined Hot Subdwarf Stars in LAMOST

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