A search for photometric variability in magnetic chemically
peculiar stars using ASAS-3 data

J 2015

A search for photometric variability in magnetic chemically peculiar stars using ASAS-3 data

BERNHARD, Klaus, Stefan HUMMERICH, Sebastian OTERO and Ernst PAUNZEN

Basic information

Original name

A search for photometric variability in magnetic chemically peculiar stars using ASAS-3 data

Authors

BERNHARD, Klaus (40 Austria), Stefan HUMMERICH (276 Germany), Sebastian OTERO (32 Argentina) and Ernst PAUNZEN (40 Austria, belonging to the institution)

Edition

ASTRONOMY & ASTROPHYSICS, LES ULIS CEDEX A, EDP SCIENCES S A, 2015, 1432-0746

Other information

Language

English

Type of outcome

Článek v odborném periodiku

Field of Study

10308 Astronomy

Country of publisher

France

Confidentiality degree

není předmětem státního či obchodního tajemství

Impact factor

Impact factor: 5.185

RIV identification code

RIV/00216224:14310/15:00085398

Organization unit

Faculty of Science

DOI

http://dx.doi.org/10.1051/0004-6361/201526424

UT WoS

000361803900138

Keywords in English

binaries: eclipsing; stars: chemically peculiar; stars: variables: general; techniques: photometric

Abstract

V originále

The (magnetic) chemically peculiar (CP) stars of the upper main sequence are well-suited laboratories for investigating the influence of magnetic fields on the stellar surface because they produce abundance inhomogeneities (spots), which results in photometric variability that is explained in terms of the oblique rotator model. CP stars exhibiting this phenomenon are normally classified as alpha2 Canum Venaticorum (ACV) variables. It is important to increase the sample of known rotational periods among CP stars by discovering new ACV variables. The ASAS-3 data were cross-correlated with the Catalogue of Ap, HgMn, and Am stars in order to analyse the light curves of bona fide CP and related stars. The light curves were downloaded and cleaned of outliers and data points with a flag indicating bad quality. Promising candidates showing a larger scatter than observed for constant stars in the corresponding magnitude range were searched for periodic signals using a standard Fourier technique. In total, we found 323 variables, from which 246 are reported here for the first time, and 77 were probably wrongly classified before. The observed variability pattern of most stars is in accordance with an ACV classification. For some cases, it is difficult to distinguish between the light curves of double-waved ACVs and the variability induced by orbital motion (ellipsoidal variables/eclipsing variables), especially for objects exhibiting very small amplitudes and/or significant scatter in their light curves. Thus, some eclipsing or rotating ellipsoidal variables might be present. However, we are confident that the given periods are the correct ones. There seems to be a possible weak correlation between the rotational period and colour, in the sense that cooler magnetic CP stars rotate more slowly. However, this correlation seems to disappear when correcting for the interstellar reddening.

Links

3SGA5916, interní kód MU

Name: Hvězdy a hvězdokupy v Magellanových mračnech (Acronym: Webda MaC)

Investor: South-Moravian Region, Incoming grants

7AMB14AT015, research and development project

Name: Nový pohled na magnetické hvězdy (Acronym: MAGSTARS)

Investor: Ministry of Education, Youth and Sports of the CR

Citovat

BERNHARD, Klaus, Stefan HUMMERICH, Sebastian OTERO and Ernst PAUNZEN. A search for photometric variability in magnetic chemically peculiar stars using ASAS-3 data. ASTRONOMY & ASTROPHYSICS. LES ULIS CEDEX A: EDP SCIENCES S A, 2015, vol. 581, September, p. "nestrankovano", 32 pp. ISSN 1432-0746. Available from: https://dx.doi.org/10.1051/0004-6361/201526424.

@article{1322160,
   author = {Bernhard, Klaus and Hummerich, Stefan and Otero, Sebastian and Paunzen, Ernst},
   article_location = {LES ULIS CEDEX A},
   article_number = {September},
   doi = {http://dx.doi.org/10.1051/0004-6361/201526424},
   keywords = {binaries: eclipsing; stars: chemically peculiar; stars: variables: general; techniques: photometric},
   language = {eng},
   issn = {1432-0746},
   journal = {ASTRONOMY & ASTROPHYSICS},
   title = {A search for photometric variability in magnetic chemically peculiar stars using ASAS-3 data},
   volume = {581},
   year = {2015}
}

TY  - JOUR
ID  - 1322160
AU  - Bernhard, Klaus - Hummerich, Stefan - Otero, Sebastian - Paunzen, Ernst
PY  - 2015
TI  - A search for photometric variability in magnetic chemically peculiar stars using ASAS-3 data
JF  - ASTRONOMY & ASTROPHYSICS
VL  - 581
IS  - September
SP  - "nestrankovano"
EP  - "nestrankovano"
PB  - EDP SCIENCES S A
SN  - 14320746
KW  - binaries: eclipsing
KW  - stars: chemically peculiar
KW  - stars: variables: general
KW  - techniques: photometric
N2  - The (magnetic) chemically peculiar (CP) stars of the upper main sequence are well-suited laboratories for investigating the influence of magnetic fields on the stellar surface because they produce abundance inhomogeneities (spots), which results in photometric variability that is explained in terms of the oblique rotator model. CP stars exhibiting this phenomenon are normally classified as alpha2 Canum Venaticorum (ACV) variables. It is important to increase the sample of known rotational periods among CP stars by discovering new ACV variables. The ASAS-3 data were cross-correlated with the Catalogue of Ap, HgMn, and Am stars in order to analyse the light curves of bona fide CP and related stars. The light curves were downloaded and cleaned of outliers and data points with a flag indicating bad quality. Promising candidates showing a larger scatter than observed for constant stars in the corresponding magnitude range were searched for periodic signals using a standard Fourier technique. In total, we found 323 variables, from which 246 are reported here for the first time, and 77 were probably wrongly classified before. The observed variability pattern of most stars is in accordance with an ACV classification. For some cases, it is difficult to distinguish between the light curves of double-waved ACVs and the variability induced by orbital motion (ellipsoidal variables/eclipsing variables), especially for objects exhibiting very small amplitudes and/or significant scatter in their light curves. Thus, some eclipsing or rotating ellipsoidal variables might be present. However, we are confident that the given periods are the correct ones. There seems to be a possible weak correlation between the rotational period and colour, in the sense that cooler magnetic CP stars rotate more slowly. However, this correlation seems to disappear when correcting for the interstellar reddening.
ER  -

BERNHARD, Klaus, Stefan HUMMERICH, Sebastian OTERO and Ernst PAUNZEN. A search for photometric variability in magnetic chemically peculiar stars using ASAS-3 data. \textit{ASTRONOMY \&{}amp; ASTROPHYSICS}. LES ULIS CEDEX A: EDP SCIENCES S A, 2015, vol.~581, September, p.~''nestrankovano'', 32 pp. ISSN~1432-0746. Available from: https://dx.doi.org/10.1051/0004-6361/201526424.

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