The observed periods of Ap and Bp stars

Catalano, F. A.; Renson, Pierre

doi:10.1051/aas:1998110

Cited by 58 publications

(54 citation statements)

References 4 publications

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“…Leone & Manfre (1996) determined the abundances of Si, Cr, and Fe (all overabundant by 0.8 dex). The photometric variability of this star was discovered by North (1992), who found the period to be 3.9124 d, as confirmed by Catalano & Renson (1998). Kazarovets et al (1999) included this star in the list of variables of the α 2 CVn type.…”

Section: Also Foundmentioning

confidence: 68%

“…Two possible periods were discovered by North (1987). In the catalogue of Catalano & Renson (1998), a period of 1.177 d is given. Effective temperatures of 12 600 and 13 200 K were determined by Glagolevskij (1994) from Q and X indices, respectively.…”

Section: Also Foundmentioning

confidence: 99%

“…It turned out that Hg is slightly overabundant in this star. Catalano & Renson (1998) placed V 1288 Aql in their list of variables as a probable B8 Hg star. Adelman et al (2004) analysed the lines of very heavy elements (Pt, Au, Hg, Tl, and Bi) in the UV spectra of 21 Aql.…”

Section: Also Foundmentioning

confidence: 99%

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Abundance analysis of prime B-type targets for asteroseismology

Niemczura¹,

Morel²,

Aerts

2009

A&A

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Aims. The main goal of the ground-based seismology support program for the CoRoT mission was to obtain photometric and spectroscopic data for stars in the fields monitored by the satellite. These ground-based observations were collected in the GAUDI archive. High-resolution spectra of more than 200 B-type stars are available in this database, and about 45% of them is analysed here. Methods. To derive the effective temperature of the stars, we used photometric indices. Surface gravities were obtained by comparing observed and theoretical Balmer line profiles. To determine the chemical abundances and rotational velocities, we used a spectrum synthesis method, which consisted of comparing the observed spectrum with theoretical ones based on the assumption of LTE. Results. Atmospheric parameters, chemical abundances, and rotational velocities were determined for 89 late-B stars. The dominant species in their spectra are iron-peak elements. The average Fe abundance is 7.24 ± 0.45 dex. The average rotational velocity is 126 km s −1 , but there are 13 and 20 stars with low and moderate V sin i values, respectively. The analysis of this sample of 89 late B-type stars reveals many chemically peculiar (CP) stars. Some of them were previously known, but at least 9 new CP candidates, among which at least two HgMn stars, are identified in our study. These CP stars as a group exhibit V sin i values lower than the stars with normal surface chemical composition.

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Section: Also Foundmentioning

confidence: 68%

Section: Also Foundmentioning

confidence: 99%

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Abundance analysis of prime B-type targets for asteroseismology

Niemczura¹,

Morel²,

Aerts

2009

A&A

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“…34, 53, and 74) were detected with EPIC/XMM-Newton by Franciosini et al (2006). In practice, they could not resolve the X-ray emission coming from the system HD 294272 ( (Joncas & Borra 1981;North 1984;Catalano & Renson 1998). Its nondetection in previous surveys with HRI/ROSAT, EPIC/XMM-Newton, and ACIS-S/Chandra may reside simply in its location in σ Orionis, at about 16 arcmin to the east of the cluster centre.…”

Section: Early-type Starsmentioning

confidence: 96%

HRC-I/ChandraX-ray observations towardsσ Orionis

Caballero

Colombo

López‐Santiago

2010

A&A

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Aims. We investigated the X-ray emission from young stars and brown dwarfs in the σ Orionis cluster (τ ∼ 3 Ma, d ∼ 385 pc) and its relation to mass, the presence of circumstellar discs, and separation to the cluster centre by taking advantage of the superb spatial resolution of the Chandra X-ray Observatory. Methods. We used public HRC-I/Chandra data from a 97.6 ks pointing towards the cluster centre and complemented them with X-ray data from IPC/Einstein, HRI/ROSAT, EPIC/XMM-Newton, and ACIS-S/Chandra together with optical and infrared photometry and spectroscopy from the literature and public catalogues. On our HRC-I/Chandra data, we measured count rates, estimated X-ray fluxes, and searched for short-term variability. We also looked for long-term variability by comparing with previous X-ray observations. Results. Among the 107 detected X-ray sources, there were 70 cluster stars with known signposts of youth, two young brown dwarfs, 12 cluster member candidates, four field dwarfs, and two galaxies with optical-infrared counterpart. The remaining sources were extragalactic. Based on a robust Poisson-χ 2 analysis, nine cluster stars displayed flares or rotational modulation during the HRC-I observations, while eight other stars and one brown dwarf showed X-ray flux variations between the HRC-I and IPC, HRI, and EPIC epochs. We constructed a cluster X-ray luminosity function from O9.5 (about 18 M ) to M6.5 (about 0.06 M ). We found: (i) that early-type stars in multiple systems or with spectroscopic peculiarities tend to display X-ray emission; (ii) that the two detected brown dwarfs and the least-massive star are among the σ Orionis objects with the highest L X /L J ratios; and (iii) that a large fraction of known classical T Tauri stars in the cluster are absent in this and other X-ray surveys. Finally, from a spatial distribution analysis, we quantified the impact of sensitivity degradation towards the HRC-I borders on the detection of faint X-ray sources and concluded that dozens X-ray σ Orionis stars and brown dwarfs still need to be detected.

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“…A catalogue of the published periods has been compiled by Catalano & Renson (1998), who continue to update it regularly (Renson & Catalano 2001). After critical evaluation of this compilation, I estimate that it contains reliably determined rotation periods for 185 magnetic CP stars, and for 3 more, meaningful lower limits of their (very long) periods.…”

Section: "Magnetic" Cp Starsmentioning

confidence: 99%

Rotation and Properties of A- and B-Type Chemically Peculiar Stars

Mathys¹

2004

Symp. - Int. Astron. Union

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Abstract. Main-sequence chemically peculiar stars of spectral types A and B, which are characterised by photospheric abundance anomalies resulting from element segregation in the stellar outer layers, rotate slower than normal stars of similar temperatures. The mechanisms by which such slow rotation is achieved are not well understood yet; different processes may be involved for different types of chemical peculiarities, including stellar magnetic fields and multiplicity. Relevant existing observational data are reviewed.

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The observed periods of Ap and Bp stars

Cited by 58 publications

References 4 publications

Abundance analysis of prime B-type targets for asteroseismology

Abundance analysis of prime B-type targets for asteroseismology

HRC-I/ChandraX-ray observations towardsσ Orionis

Rotation and Properties of A- and B-Type Chemically Peculiar Stars

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