Oxygen- and carbon-rich variable red giant populations in the Magellanic Clouds from EROS, OGLE, MACHO, and 2MASS photometry

Wiśniewski, M.; Marquette, J. B.; Beaulieu, J. P.; Schwarzenberg‐Czerny, A.; Tisserand, Patrick; Lesquoy, É.

doi:10.1051/0004-6361/201014319

Cited by 9 publications

(7 citation statements)

References 56 publications

(82 reference statements)

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“…templates, 229 Miras with high-quality 2MASS photometry are also included in the same plot. In Figure 5, 99.1% of the templates are sufficiently cool to be characterized by the empirical colors of giant stars, J−K s > 1 mag (Wiśniewski et al 2011), as well as bright, K s < 12 mag. Two outliers with J−K s < 1 are relatively bluer O-rich Miras.…”

Section: Mass Cutsmentioning

confidence: 99%

Mira Variable Stars from LAMOST DR4 Data: Emission Features, Temperature Types, and Candidate Selection

Yao

Liu

Deng

et al. 2017

ApJS

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Based on an extensive spectral study of a photometrically confirmed sample of Mira variables, we find a relationship between relative Balmer emission-line strength and spectral temperature of O-rich Mira stars. The F Hδ /F Hγ flux ratio increases from less than unity to five as stars cool down from M0 to M10, which is likely driven by increasing TiO absorption above the deepest shock-emitting regions. We also discuss the relationship between the equivalent widths of the Balmer emission lines and the photometric luminosity phase of our Mira sample stars. Using our 291 Mira spectra as templates for reference, 191 Mira candidates are newly identified from the LAMOST DR4 catalog. We summarize the criteria adopted to select Mira candidates based on emission-line indices and molecular absorption bands. This enlarged spectral sample of Mira variables has the potential to contribute significantly to our knowledge of the optical properties of Mira stars and will facilitate further studies of these late-type, long-period variables.

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Section: Mass Cutsmentioning

confidence: 99%

Mira Variable Stars from LAMOST DR4 Data: Emission Features, Temperature Types, and Candidate Selection

Yao

Liu

Deng

et al. 2017

ApJS

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“…Our recent understanding of how M giants oscillate was obtained from ground-based surveys such as MACHO, OGLE, and EROS (e.g. Wood & Sebo 1996;Alard et al 2001;Lebzelter et al 2002;Kiss & Bedding 2003;Soszynski et al 2007;Riebel et al 2010;Wiśniewski et al 2011;Soszyński et al 2013), as well as solar neighbourhood observations (Tabur et al 2010).…”

Section: Introductionmentioning

confidence: 99%

The variability behaviour of CoRoT M-giant stars

Lopes

Neves

Leão

et al. 2015

A&A

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Context. For six years the Convection, Rotation, and planetary Transits (CoRoT) space mission has been acquiring photometric data from more than 100 000 point sources towards and directly opposite the inner and outer regions of the Galaxy. The high temporal resolution of the CoRoT data, combined with the wide time span of the observations, enabled the study of short-and long-time variations in unprecedented detail. Aims. The aim of this work is to study the variability and evolutionary behaviour of M-giant stars using CoRot data. Methods. From the initial sample of 2534 stars classified as M giants in the CoRoT databases, we selected 1428 targets that exhibit well defined variability, by visual inspection. Then, we defined three catalogues: C1 -stars with T eff < 4200 K and LCs displaying semi-sinusoidal signatures; C2 -rotating variable candidates with T eff > 4200 K; C3 -long-period variable candidates (with LCs showing a variability period up to the total time span of the observations). The variability period and amplitude of C1 stars were computed using Lomb-Scargle and harmonic fit methods. Finally, we used C1 and C3 stars to study the variability behaviour of M-giant stars. Results. The trends found in the V − I vs. J − K colour-colour diagram are in agreement with standard empirical calibrations for M giants. The sources located towards the inner regions of the Galaxy are distributed throughout the diagram, while the majority of the stars towards the outer regions of the Galaxy are spread between the calibrations of M giants and the predicted position for carbon stars. The stars classified as supergiants follow a different sequence from the one found for giant stars. We also performed a Kolmogorov-Smirnov (KS) test of the period and amplitude of stars towards the inner and outer regions of the Galaxy. We obtained a low probability that the two samples came from the same parent distribution. The observed behaviour of the period-amplitude and period-effective temperature (T eff ) diagrams are, in general, in agreement with those found for Kepler sources and ground based photometry, with pulsation being the dominant cause responsible for the observed modulation. We also conclude that short-time variations on M-giant stars do not exist or are very rare, and the few cases we found are possibly related to biases or background stars.

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“…The (J − K s ) 0 colour of bright carbon stars is known to be greater than 1.4 (Wiśniewski et al 2011). Indeed, carbon stars seem to appear well separated from oxygen-rich AGB stars in the colour-magnitude diagram (see Fig.…”

Section: Colour Selectionmentioning

confidence: 98%

Carbon stars as standard candles: I. The luminosity function of carbon stars in the Magellanic Clouds

Ripoche,

Heyl,

Parada

et al. 2020

Preprint

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Our goal in this paper is to derive a carbon-star luminosity function that will eventually be used to determine distances to galaxies at 50-60 Mpc and hence yield a value of the Hubble constant. Cool N-type carbon stars exhibit redder near-infrared colours than oxygen-rich stars. Using Two Micron All Sky Survey near-infrared photometry and the Gaia Data Release 2, we identify carbon stars in the Magellanic Clouds (MC) and the Milky Way (MW). Carbon stars in the MC appear as a distinct horizontal feature in the near-infrared ((J − K s ) 0 , M J ) colour-magnitude diagram. We build a colour selection (1.4 < (J − K s ) 0 < 2) and derive the luminosity function of the colourselected carbon stars. We find the median absolute magnitude and the dispersion, in the J band, for the Large Magellanic Cloud and the Small Magellanic Cloud to be, respectively, ( MJ = −6.284 ± 0.004, σ = 0.352 ± 0.005) and ( MJ = −6.160 ± 0.015, σ = 0.365 ± 0.014). The difference between the MC may be explained by the lower metallicity of the Small Magellanic Cloud, but in any case it provides limits on the type of galaxy whose distance can be determined with this technique. To account for metallicity effects, we developed a composite magnitude, named C, for which the errorweighted mean C magnitude of the MC are equal. Thanks to the next generation of telescopes (JWST, ELT, TMT ), carbon stars could be detected in MC-type galaxies at distances out to 50-60 Mpc. The final goal is to eventually try and improve the measurement of the Hubble constant while exploring the current tensions related to its value.

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Oxygen- and carbon-rich variable red giant populations in the Magellanic Clouds from EROS, OGLE, MACHO, and 2MASS photometry

Cited by 9 publications

References 56 publications

Mira Variable Stars from LAMOST DR4 Data: Emission Features, Temperature Types, and Candidate Selection

Mira Variable Stars from LAMOST DR4 Data: Emission Features, Temperature Types, and Candidate Selection

The variability behaviour of CoRoT M-giant stars

Carbon stars as standard candles: I. The luminosity function of carbon stars in the Magellanic Clouds

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