The anomalous Cepheid XZ Ceti

L. Szabados, L. L. Kiss, A. Derekas

Research output: Contribution to journalArticle

10 Citations (Scopus)

Abstract

Aims. XZ Ceti is the only known anomalous Cepheid in the Galactic field. Being the nearest and brightest such variable star, a detailed study of XZ Ceti may shed light on the behaviour of anomalous Cepheids whose representatives have been mostly detected in external galaxies. Methods. CCD photometric and radial velocity observations have been obtained. The actual period and amplitude of pulsation were determined by Fourier analysis. The long timescale behaviour of the pulsation period was studied by the method of the O-C diagram using the archival Harvard photographic plates and published photometric data. Results. XZ Ceti differs from the ordinary classical Cepheids in several respects. Its most peculiar feature is cycle-to-cycle variability of the light curve. The radial velocity phase curve is not stable either. The pulsation period is subjected to strong changes on various timescales, including a very short one. The ratio of amplitudes determined from the photometric and radial velocity observations indicates that this Cepheid performs an overtone pulsation, in accord with the other known anomalous Cepheid in our Galaxy, BL Boo (V19 in the globular cluster NGC 5466). Conclusions. Continued observations are necessary to study the deviations from regularity to determine their timescale, as well as to confirm the binarity of XZ Ceti and to study its role in the observed peculiar behaviour.

Original languageEnglish
Pages (from-to)613-618
Number of pages6
JournalAstronomy and Astrophysics
Volume461
Issue number2
DOIs
Publication statusPublished - Jan 2007

Fingerprint

radial velocity
timescale
galaxies
photographic plates
cycles
variable stars
Fourier analysis
phase velocity
globular clusters
regularity
light curve
charge coupled devices
diagram
diagrams
deviation
harmonics
curves
method
analysis

Keywords

  • Binaries: spectroscopic
  • Cepheids
  • Stars: evolution
  • Stars: individual: BL Boo
  • Stars: individual: XZ Cet

ASJC Scopus subject areas

  • Space and Planetary Science

Cite this

The anomalous Cepheid XZ Ceti. / Szabados, L.; Kiss, L. L.; Derekas, A.

In: Astronomy and Astrophysics, Vol. 461, No. 2, 01.2007, p. 613-618.

Research output: Contribution to journalArticle

Szabados, L. ; Kiss, L. L. ; Derekas, A. / The anomalous Cepheid XZ Ceti. In: Astronomy and Astrophysics. 2007 ; Vol. 461, No. 2. pp. 613-618.
@article{ee2f3df9046a4ec49455f174092a62c0,
title = "The anomalous Cepheid XZ Ceti",
abstract = "Aims. XZ Ceti is the only known anomalous Cepheid in the Galactic field. Being the nearest and brightest such variable star, a detailed study of XZ Ceti may shed light on the behaviour of anomalous Cepheids whose representatives have been mostly detected in external galaxies. Methods. CCD photometric and radial velocity observations have been obtained. The actual period and amplitude of pulsation were determined by Fourier analysis. The long timescale behaviour of the pulsation period was studied by the method of the O-C diagram using the archival Harvard photographic plates and published photometric data. Results. XZ Ceti differs from the ordinary classical Cepheids in several respects. Its most peculiar feature is cycle-to-cycle variability of the light curve. The radial velocity phase curve is not stable either. The pulsation period is subjected to strong changes on various timescales, including a very short one. The ratio of amplitudes determined from the photometric and radial velocity observations indicates that this Cepheid performs an overtone pulsation, in accord with the other known anomalous Cepheid in our Galaxy, BL Boo (V19 in the globular cluster NGC 5466). Conclusions. Continued observations are necessary to study the deviations from regularity to determine their timescale, as well as to confirm the binarity of XZ Ceti and to study its role in the observed peculiar behaviour.",
keywords = "Binaries: spectroscopic, Cepheids, Stars: evolution, Stars: individual: BL Boo, Stars: individual: XZ Cet",
author = "L. Szabados and Kiss, {L. L.} and A. Derekas",
year = "2007",
month = "1",
doi = "10.1051/0004-6361:20065690",
language = "English",
volume = "461",
pages = "613--618",
journal = "Astronomy and Astrophysics",
issn = "0004-6361",
publisher = "EDP Sciences",
number = "2",

}

TY - JOUR

T1 - The anomalous Cepheid XZ Ceti

AU - Szabados, L.

AU - Kiss, L. L.

AU - Derekas, A.

PY - 2007/1

Y1 - 2007/1

N2 - Aims. XZ Ceti is the only known anomalous Cepheid in the Galactic field. Being the nearest and brightest such variable star, a detailed study of XZ Ceti may shed light on the behaviour of anomalous Cepheids whose representatives have been mostly detected in external galaxies. Methods. CCD photometric and radial velocity observations have been obtained. The actual period and amplitude of pulsation were determined by Fourier analysis. The long timescale behaviour of the pulsation period was studied by the method of the O-C diagram using the archival Harvard photographic plates and published photometric data. Results. XZ Ceti differs from the ordinary classical Cepheids in several respects. Its most peculiar feature is cycle-to-cycle variability of the light curve. The radial velocity phase curve is not stable either. The pulsation period is subjected to strong changes on various timescales, including a very short one. The ratio of amplitudes determined from the photometric and radial velocity observations indicates that this Cepheid performs an overtone pulsation, in accord with the other known anomalous Cepheid in our Galaxy, BL Boo (V19 in the globular cluster NGC 5466). Conclusions. Continued observations are necessary to study the deviations from regularity to determine their timescale, as well as to confirm the binarity of XZ Ceti and to study its role in the observed peculiar behaviour.

AB - Aims. XZ Ceti is the only known anomalous Cepheid in the Galactic field. Being the nearest and brightest such variable star, a detailed study of XZ Ceti may shed light on the behaviour of anomalous Cepheids whose representatives have been mostly detected in external galaxies. Methods. CCD photometric and radial velocity observations have been obtained. The actual period and amplitude of pulsation were determined by Fourier analysis. The long timescale behaviour of the pulsation period was studied by the method of the O-C diagram using the archival Harvard photographic plates and published photometric data. Results. XZ Ceti differs from the ordinary classical Cepheids in several respects. Its most peculiar feature is cycle-to-cycle variability of the light curve. The radial velocity phase curve is not stable either. The pulsation period is subjected to strong changes on various timescales, including a very short one. The ratio of amplitudes determined from the photometric and radial velocity observations indicates that this Cepheid performs an overtone pulsation, in accord with the other known anomalous Cepheid in our Galaxy, BL Boo (V19 in the globular cluster NGC 5466). Conclusions. Continued observations are necessary to study the deviations from regularity to determine their timescale, as well as to confirm the binarity of XZ Ceti and to study its role in the observed peculiar behaviour.

KW - Binaries: spectroscopic

KW - Cepheids

KW - Stars: evolution

KW - Stars: individual: BL Boo

KW - Stars: individual: XZ Cet

UR - http://www.scopus.com/inward/record.url?scp=33846397755&partnerID=8YFLogxK

UR - http://www.scopus.com/inward/citedby.url?scp=33846397755&partnerID=8YFLogxK

U2 - 10.1051/0004-6361:20065690

DO - 10.1051/0004-6361:20065690

M3 - Article

AN - SCOPUS:33846397755

VL - 461

SP - 613

EP - 618

JO - Astronomy and Astrophysics

JF - Astronomy and Astrophysics

SN - 0004-6361

IS - 2

ER -