Observation of periodic variable stars towards the Galactic spiral arms by EROS II

Derue, F.; Marquette, J. B.; Lupone, S.; Afonso, C.; Alard, C.; Albert, J.; Amadon, Alexis; Andersen, J.; Ansari, R.; Aubourg, É.; Bareyre, P.; Bauer, F. F.; Beaulieu, J. P.; Blanc, G.; Bouquet, A.; Char, S.; Charlot, X.; Couchot, F.; Coutures, C.; Ferlet, R.; Fouqué, P.; Glicenstein, J. F.; Goldman, B.; Gould, Andrew; Graff, D.; Gros, M.; Haïssinski, J.; Hamilton, J. C.; Hardin, D.; Kat, J. de; Kim, A.; Lasserre, T.; Guillou, L. Le; Lesquoy, É.; Loup, C.; Magneville, C.; Mansoux, B.; Maurice, É.; Milsztajn, A.; Moniez, M.; Palanque-Delabrouille, N.; Perdereau, O.; Prévôt, L.; Regnault, Nicolas; Rich, J.; Spiro, M.; Vidal‐Madjar, A.; Vigroux, L.; Zylberajch, S.

doi:10.1051/0004-6361:20020570

Cited by 30 publications

(23 citation statements)

References 17 publications

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“…The light curves of individual stars were constructed from fixed positions on templates using PEIDA, a software dedicated to the photometry of EROS-2 images (Ansari 1996). The stars were labelled according to the rules defined for the catalogue by Derue et al (2002). In the present paper, we study the star EROS2 J005135-714459(sm0060n13842), hereafter sm0060n13842, whose J2000 coordinates are 00:51:35.65; −71:44:59.5 (galactic: l = 302.915 • , b = −45.378 • ).…”

Section: Photometric Setup and Data Acquisitionmentioning

confidence: 99%

Discovery of a peculiar Cepheid-like star towards the northern edge of the Small Magellanic Cloud

Marquette¹,

Tisserand

François

et al. 2008

A&A

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Context. For seven years, the EROS-2 project obtained a mass of photometric data on variable stars. We present a peculiar Cepheid-like star, in the direction of the Small Magellanic Cloud, which demonstrates unusual photometric behaviour over a short time interval. Aims. We report on data of the photometry acquired by the MARLY telescope and spectroscopy from the EFOSC instrument for this star, called EROS2 J005135-714459(sm0060n13842), which resembles the unusual Cepheid HR 7308. Methods. The light curve of our target is analysed using the Analysis of Variance method to determine a pulsational period of 5.5675 days. A fit of time-dependent Fourier coefficients is performed and a search for proper motion is conducted. Results. The light curve exhibits a previously unobserved and spectacular change in both mean magnitude and amplitude, which has no clear theoretical explanation. Our analysis of the spectrum implies a radial velocity of 104 km s −1 and a metallicity of −0.4 ± 0.2 dex. In the direction of right ascension, we measure a proper motion of 17.4 ± 6.0 mas yr −1 using EROS astrometry, which is compatible with data from the NOMAD catalogue. Conclusions. The nature of EROS2 J005135-714459(sm0060n13842) remains unclear. For this star, we may have detected a non-zero proper motion, which would imply that it is a foreground object. Its radial velocity, pulsational characteristics, and photometric data, however, suggest that it is instead a Cepheid-like object located in the SMC. In such a case, it would present a challenge to conventional Cepheid models.

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Section: Photometric Setup and Data Acquisitionmentioning

confidence: 99%

Discovery of a peculiar Cepheid-like star towards the northern edge of the Small Magellanic Cloud

Marquette¹,

Tisserand

François

et al. 2008

A&A

Self Cite

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“…The photometry of individual images and the reconstruction of the light curves were processed using the Peida package which has been specifically developped for the EROS experiment (Ansari 1996). An estimation of the photometric accuracy is discussed by Derue et al (2002). Recently all available SMC data were used to recompute the entire sample of light curves.…”

Section: Observational Datamentioning

confidence: 99%

EROS 2 photometry of probable R Coronae Borealis stars in the Small Magellanic Cloud

Tisserand

Marquette²,

Beaulieu³

et al. 2004

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“…-Column 1: EROS-2 ID of the star according to the definitions by Derue et al (2002). -Columns 2, 3: equatorial coordinates, RA and Dec, for the epoch J2000.…”

Section: Catalogmentioning

confidence: 99%

Long period variables in the Large Magellanic Cloud from the EROS-2 survey

Spano

Mowlavï

Eyer

et al. 2011

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Context. The EROS-2 survey has produced a database of millions of time series from stars monitored for more than six years, allowing us to classify some of their sources into different variable star types. Among the so-called, long period variables (LPVs), which are known to follow particular sequences in the period-luminosity diagram, we find long secondary period variables whose variability origin remains a matter of debate. Aims. We analyze data for the 856 864 variable stars that have been discovered in the Large Magellanic Cloud (LMC) that are present in the EROS-2 database, to detect, classify, and characterize LPVs. Methods. Our method for identifying LPVs is based on the statistical Abbe test. It investigates the regularity of the light curve with respect to the survey duration in order to extract candidates with long-term variability. The period search is performed using Deeming, Lomb-Scargle, and generalized Lomb-Scargle methods, combined with a Fourier series fit. Color−magnitude, period-magnitude, and period-amplitude diagrams are used to characterize our candidates.Results. We present a catalog of 43 551 LPV candidates for the Large Magellanic Cloud. For each of them, we provide up to five periods, a mean magnitude in EROS-2, 2MASS, and Spitzer bands, B E −R E color, R E amplitude, and spectral type. We use infrared data to distinguish between RGB, O-rich, C-rich, and extreme AGB stars. Properties of our LPV candidates are investigated by analyzing period-luminosity and period-amplitude diagrams.

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Observation of periodic variable stars towards the Galactic spiral arms by EROS II

Cited by 30 publications

References 17 publications

Discovery of a peculiar Cepheid-like star towards the northern edge of the Small Magellanic Cloud

Discovery of a peculiar Cepheid-like star towards the northern edge of the Small Magellanic Cloud

EROS 2 photometry of probable R Coronae Borealis stars in the Small Magellanic Cloud

Long period variables in the Large Magellanic Cloud from the EROS-2 survey

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