Magnetic fields of chemically peculiar stars. I. The catalog of magnetic CP stars

Romanyuk, I. I.; Kudryavtsev, D. O.

doi:10.1134/s1990341308020053

Cited by 44 publications

(53 citation statements)

References 85 publications

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“…The catalogues by Romanyuk (2000) and Bychkov et al (2003) have provided the core of the sample of the early-type stars with definite magnetic field detections. Since the present study focuses on the classical magnetic Ap/Bp stars, we have selected objects with the SrCrEu, Si, and/or He chemical peculiarities for which reliable detection of magnetic field has been obtained with one of the two direct methods: spectropolarimetric or photopolarimetric measurement of the disk-averaged line of sight (longitudinal) magnetic field (Mathys 1991;Borra & Landstreet 1980) and the mean field modulus diagnostic using resolved Zeeman split spectral line profiles (Mathys et al 1997).…”

Section: Known Magnetic Starsmentioning

confidence: 99%

“…Given this absence of the solid evidence for the presence of significant surface fields in HgMn and Am stars, all such objects were eliminated from our list of magnetic stars. We emphasise that in nearly all cases when non-zero longitudinal field determinations are reported for HgMn or Am stars in the catalogues compiled by Romanyuk (2000) and Bychkov et al (2003), the original measurements date back to the early lowprecision spectropolarimetric observations by Babcock (1958).…”

Section: Known Magnetic Starsmentioning

confidence: 99%

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Evolutionary state of magnetic chemically peculiar stars

Kochukhov¹,

Bagnulo

2006

A&A

202

242

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Context. The photospheres of about 5-10% of the upper main sequence stars exhibit remarkable chemical anomalies. Many of these chemically peculiar (CP) stars have a global magnetic field, the origin of which is still a matter of debate. Aims. We present a comprehensive statistical investigation of the evolution of magnetic CP stars, aimed at providing constraints to the theories that deal with the origin of the magnetic field in these stars. Methods. We have collected from the literature data for 150 magnetic CP stars with accurate Hipparcos parallaxes. We have retrieved from the ESO archive 142 FORS1 observations of circularly polarized spectra for 100 stars. From these spectra we have measured the mean longitudinal magnetic field, and discovered 48 new magnetic CP stars (five of which belonging to the rare class of rapidly oscillating Ap stars). We have determined effective temperature and luminosity, then mass and position in the H-R diagram for a final sample of 194 magnetic CP stars. Results. We found that magnetic stars with M > 3 M are homogeneously distributed along the main sequence. Instead, there are statistical indications that lower mass stars (especially those with M ≤ 2 M ) tend to concentrate in the centre of the main sequence band. We show that this inhomogeneous age distribution cannot be attributed to the effects of random errors and small number statistics. Our data suggest also that the surface magnetic flux of CP stars increases with stellar age and mass, and correlates with the rotation period. For stars with M > 3 M , rotation periods decrease with age in a way consistent with the conservation of the angular momentum, while for less massive magnetic CP stars an angular momentum loss cannot be ruled out. Conclusions. The mechanism that originates and sustains the magnetic field in the upper main sequence stars may be different in CP stars of different mass.

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Section: Known Magnetic Starsmentioning

confidence: 99%

Section: Known Magnetic Starsmentioning

confidence: 99%

Evolutionary state of magnetic chemically peculiar stars

Kochukhov¹,

Bagnulo

2006

A&A

202

242

View full text Add to dashboard Cite

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“…We can thus estimate that at least 90% of all magnetic CP stars in our list (Romanyuk and Kudryavtsev 2008)) have average surface field B s weaker than or equal to 10 kG. We find only a few objects with stronger fields (with B s greater than 20 kG) in our list.…”

Section: Discussionmentioning

confidence: 79%

“…Now there are more then 350 stars known to be magnetic CP ones (see our catalog (Romanyuk and Kudryavtsev 2008)), it is the most numerous group of stars with measured magnetic fields. The data of magnetism of 300 stars are based on measurements of longitudinal field component B e , and the surface field is measured from split Zeeman components only for 50 of these stars.…”

Section: The Catalogmentioning

confidence: 99%

First magnetic stars

Romanyuk

Kudryavtsev

2008

Proc. IAU

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Abstract. This contribution dedicated to the analysis of the magnetism of chemically peculiar (CP) stars of the upper Main Sequence. We use our own measurements and published data to compile a catalog of magnetic CP stars containing a total of 326 objects with confidently detected magnetic fields and 29 stars which are very likely to possess magnetic field. Our analysis shows that the number of magnetic CP stars decreases with increasing field strength in accordance with exponential law, hotter and faster rotating stars have stronger fields. Intensity of depressions in the continua correlates with the magnetic field strength.

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“…A sample of objects for observations was based on the Catalog of Magnetic Stars (Romanyuk & Kudryavtsev 2008). It contains a list of 355 chemically peculiar objects (mostly Ap/Bp) with detected global magnetic fields.…”

Section: Samplementioning

confidence: 99%

Binary and multiple magnetic Ap/Bp stars

Растегаев¹,

Balega²,

Dyachenko³

et al. 2013

Proc. IAU

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Abstract. We present the results of speckle interferometric observations of 273 magnetic stars most of which are Ap/Bp type. All observations were made at the 6-m telescope of the Special Astrophysical Observatory of the Russian Academy of Sciences. We resolved 58 binary and 5 triple stars into individual components. Almost half of these stars were astrometrically resolved for the first time. The fraction of speckle interferometric binaries/multiples in the sample of stars with confirmed magnetic fields is 23%. We expect that the total fraction of binaries/multiples in the sample with account for spectroscopic short-period systems and wide common proper motion pairs can be twice higher. The detected speckle components have a prominent peak in the ρ distribution that corresponds to the closest resolved pairs. Full version of present paper is available in electronic form at http://arxiv.org/abs/1308.3168.Keywords. magnetic stars, binary and multiple stars, speckle interferometry SampleA sample of objects for observations was based on the Catalog of Magnetic Stars (Romanyuk & Kudryavtsev 2008). It contains a list of 355 chemically peculiar objects (mostly Ap/Bp) with detected global magnetic fields. We added 17 new magnetic stars discovered after the publication of the catalog. Therefore the total number of stars in the sample is 372. For the majority of stars in the list (322 objects) only the value of the longitudinal component of the field Be is known. For 48 stars the surface fields are determined from the splitting of Zeeman components. The vast majority of the sample objects are brighter than 10 m in the V -band. The stars are uniformly distributed on the celestial sphere, although a relatively small number (about 20%) of objects belong to open clusters of different ages. The BTA can capture only 273 objects from our sample with declinations δ > −30 • . ObservationsThe speckle interferometric observations of 273 magnetic CP stars were carried out at the BTA in 2009-2012. They were performed with the speckle interferometer engineered at the SAO RAS (Maksimov et al. 2009). We used the PhotonMAX512 camera based on an internal electron multiplying CCD97 (EMCCD) produced by Princeton Instruments with a 512×512 pixel array. The limiting magnitude of our speckle interferometer is ≈ 15 m in the V -band depending on seeing conditions. Basically we employed two filters: 550/20 and 800/100 nm (central wavelength/bandwidth). We took 2000 short exposure images in each filter for almost all observed objects. High quantum efficiency and linearity of the detector permits the maximum magnitude difference between the components to reach up to 5-6 m depending on angular separation and weather conditions (Fig.

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Magnetic fields of chemically peculiar stars. I. The catalog of magnetic CP stars

Cited by 44 publications

References 85 publications

Evolutionary state of magnetic chemically peculiar stars

Evolutionary state of magnetic chemically peculiar stars

First magnetic stars

Binary and multiple magnetic Ap/Bp stars

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