Variable stars in the Magellanic Clouds - II. The data and infrared properties

Ita, Yoshifusa; Tanabé, Toshihiko; Matsunaga, Noriyuki; Nakajima, Yasushi; Nagashima, Chie; Nagayama, Takahiro; Kato, Daisuke; Kurita, Mikio; Nagata, T.; Sato, Shuji; Tamura, Motohide; Nakaya, Hidehiko; Nakada, Y.

doi:10.1111/j.1365-2966.2004.08126.x

Cited by 80 publications

(98 citation statements)

References 33 publications

(50 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…note that C-stars have a larger amplitude than O-stars. Ita et al (2004a) confirm that O-and C-rich Miras follow different period vs. (J − K) colour relations (Feast et al 1989). The I-band amplitude of C-rich Miras tends to grow with the redder mean (J − K) colour, while the amplitude of O-rich Miras is colour independent (Matsunaga et al 2005).…”

Section: Introductionsupporting

confidence: 59%

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

Wiśniewski

Marquette

Beaulieu

et al. 2011

A&A

View full text Add to dashboard Cite

Context. The carbon-to-oxygen (C/O) ratio of asymptotic giant branch (AGB) stars constitutes an important index of evolutionary and environment/metallicity factor. Aims. We develop a method for mass C/O classification of AGBs in photometric surveys without using periods. Methods. For this purpose we rely on the slopes in the tracks of individual stars in the colour-magnitude diagram. Results. We demonstrate that our method enables the separation of C-rich and O-rich AGB stars with little confusion. For the Magellanic Clouds we demonstrate that this method works for several photometric surveys and filter combinations. As we rely on no period identification, our results are relatively insensitive to the phase coverage, aliasing, and time-sampling problems that plague period analyses. For a subsample of our stars, we verify our C/O classification against published C/O catalogues. With our method we are able to produce C/O maps of the entire Magellanic Clouds. Conclusions. Our purely photometric method for classification of C-and O-rich AGBs constitutes a method of choice for large, near-infrared photometric surveys. Because our method depends on the slope of colour-magnitude variation but not on magnitude zero point, it remains applicable to objects with unknown distances.

show abstract

Section: Introductionsupporting

confidence: 59%

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

Wiśniewski

Marquette

Beaulieu

et al. 2011

A&A

View full text Add to dashboard Cite

show abstract

“…They also noted that C-stars have a larger amplitude with respect to M-stars, contrary to what was derived for the LMC AGB stars, where both types showed a similar amplitude distribution (Cioni et al 2001). Studying a much larger sample of C and M LPVs in both Magellanic Clouds, Ita et al (2004b) confirmed that O-and C-rich Miras follow different period vs. (J − K) colour relations (Feast et al 1989), that C-rich Miras tend to have greater I-band amplitudes at redder J − K colour, and that the amplitudes of O-rich Miras are independent of colour. Groenewegen (2004, G04) reached similar conclusions.…”

Section: Introductionmentioning

confidence: 77%

Pulsation properties of C stars in the Small Magellanic Cloud

Raimondo

Cioni

Rejkuba

et al. 2005

A&A

View full text Add to dashboard Cite

Abstract.A sample of carbon-rich stars (C-stars) in the Small Magellanic Cloud (SMC) was selected from the combined 2MASS and DENIS catalogues on the basis of their J − K s colour. This sample was extended to include confirmed C-stars from the Rebeirot et al. (1993) spectroscopic atlas. In this combined sample (N = 1149), a smaller number (N = 1079) were found to have MACHO observations. For this sub-sample, light curves were determined and 919 stars were found to have high quality light-curves with amplitudes of at least 0.05 mag. Of these stars, only 4% have a well-defined single period -most of these have multiple well-defined periods, while 15% have highly irregular light-curves. The distribution of the logarithm of the period versus magnitude, colour, period ratio (if applicable), and amplitude was analyzed and compared with previous works. Variable C-stars are distributed in three sequences: B, C, and D from Wood et al. (1999), and do not populate sequences with periods shorter than log P ∼ 1.5. Stellar ages and masses were estimated using stellar evolutionary models.

show abstract

“…Ita et al (2004) and Groenewegen (2004) calculated the period of variation to be 361 d and 358.6 ± 0.136 d respectively. Ita et al (2004) also reported a mean I magnitude of 17.483 mag and a peak-to-peak amplitude of 1.865 mag. The OGLE-III catalog lists the mean magnitude as 17.586 mag.…”

Section: Variability In Optical and Nir Datamentioning

confidence: 99%

“…Ita et al (2004) and Groenewegen (2004) crossmatched the OGLE-II data with the IRSF LMC Survey (Kato et al 2007), DENIS (Epchtein et al 1999) and 2MASS All-Sky Release (Cutri et al 2003) NIR catalogs and fit the light curves to obtain variability periods and amplitudes. Ita et al (2004) and Groenewegen (2004) calculated the period of variation to be 361 d and 358.6 ± 0.136 d respectively. Ita et al (2004) also reported a mean I magnitude of 17.483 mag and a peak-to-peak amplitude of 1.865 mag.…”

Section: Variability In Optical and Nir Datamentioning

confidence: 99%

The mass-loss return from evolved stars to the Large Magellanic Cloud

Srinivasan

Sargent

Matsuura

et al. 2010

A&A

View full text Add to dashboard Cite

We present a radiative transfer model for the circumstellar dust shell around a Large Magellanic Cloud (LMC) long-period variable (LPV) previously studied as part of the Optical Gravitational Lensing Experiment (OGLE) survey of the LMC. OGLE LMC LPV 28579 (SAGE J051306.40-690946.3) is a carbon-rich asymptotic giant branch (AGB) star for which we have Spitzer broadband photometry and spectra from the SAGE and SAGE-Spec programs along with broadband UBVIJHK s photometry. By modeling this source, we obtain a baseline set of dust properties to be used in the construction of a grid of models for carbon stars. We reproduce the spectral energy distribution of the source using a mixture of amorphous carbon and silicon carbide with 15% SiC by mass. The grain sizes are distributed according to the KMH model, with γ = 3.5, a min = 0.01 μm and a 0 = 1.0 μm. The best-fit model produces an optical depth of 0.28 for the dust shell at the peak of the SiC feature (11.3 μm), with an inner radius of about 1430 R or 4.4 times the stellar radius. The temperature at this inner radius is 1310 K. Assuming an expansion velocity of 10 km s −1 , we obtain a dust mass-loss rate of 2.5 × 10 −9 M yr −1 . We calculate a 15% variation in this mass-loss rate by testing the sensitivity of the fit to variation in the input parameters. We also present a simple model for the molecular gas in the extended atmosphere that could give rise to the 13.7 μm feature seen in the spectrum. We find that a combination of CO and C 2 H 2 gas at an excitation temperature of about 1000 K and column densities of 3 × 10 21 cm −2 and 10 19 cm −2 respectively are able to reproduce the observations. Given that the excitation temperature is close to the temperature of the dust at the inner radius, most of the molecular contribution probably arises from this region. The luminosity corresponding to the first epoch of SAGE observations is 6580 L . For an effective temperature of about 3000 K, this implies a stellar mass of 1.5−2 M and an age of 1−2.5 Gyr for OGLE LMC LPV 28579. We calculate a gas mass-loss rate of 5.0 × 10 −7 M yr −1 assuming a gas:dust ratio of 200. This number is comparable to the gas mass-loss rates estimated from the period, color and 8 μm flux of the source.

show abstract

Variable stars in the Magellanic Clouds - II. The data and infrared properties

Cited by 80 publications

References 33 publications

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

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

Pulsation properties of C stars in the Small Magellanic Cloud

The mass-loss return from evolved stars to the Large Magellanic Cloud

Contact Info

Product

Resources

About