Carbon stars

Evans, T. Lloyd

doi:10.1007/s12036-010-0017-6

Cited by 40 publications

(38 citation statements)

References 267 publications

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“…It is certainly carbon rich, but its infrared spectrum does not show silicate emission (Speck et al 2006). Rather, it has some of the deepest acetylene absorption ever detected in the 12-16 µm resis is that the oxygen-rich dust, a remnant of previous mass loss while the star was oxygenrich, is stored in a disk around a binary system, where it could survive long enough for detection (Lloyd Evans 1990, and this remains the most likely explanation (Yamamura et al 2000;Lloyd Evans 2010). The strong crystalline silicate features in the spectrum are also consistent with the notion of a disk (e.g., Molster et al 1999;Gielen et al 2008Gielen et al , 2011.…”

Section: Msx Smc 134mentioning

confidence: 99%

Characterizing the Population of Bright Infrared Sources in the Small Magellanic Cloud

Kraemer

Sloan

Wood

et al. 2017

ApJ

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We used Spitzer's Infrared Spectrograph (IRS) to observe stars in the Small Magellanic Cloud (SMC) selected from the Midcourse Space Experiment (MSX) Point Source Catalog. We concentrate on the dust properties of oxygen-rich evolved stars, which show less alumina than Galactic stars. This difference may arise from the SMC's lower metallicity, but it could be a selection effect: the SMC sample includes more stars which are brighter and thus more massive. The distribution of SMC stars along the silicate sequence looks more like that of Galactic red supergiants than asymptotic giant branch stars (AGBs). While many are definitively AGBs, several SMC stars show evidence of hot bottom burning. Other sources show mixed chemistry (oxygen-rich and carbon-rich features), including supergiants with PAH emission. MSX SMC 134 may be the first confirmed silicate/carbon star in the SMC, and MSX SMC 049 is a post-AGB candidate. MSX SMC 145, previously a candidate OH/IR star, is actually an AGB star with a background galaxy at z=0.16 along the same line-of-sight. We consider the overall characteristics of all the MSX sources, the most infrared-bright objects in the SMC, in light of Spitzer's higher sensitivity and resolution, and compare them with the object types expected from the original selection criteria. This population represents what will be seen in more distant galaxies by the James Webb Space Telescope (JWST). Color-color diagrams using the IRS spectra and JWST mid-infrared filters show how one can separate evolved stars from young stellar objects (YSOs) and distinguish among different YSO classes.

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Section: Msx Smc 134mentioning

confidence: 99%

Characterizing the Population of Bright Infrared Sources in the Small Magellanic Cloud

Kraemer

Sloan

Wood

et al. 2017

ApJ

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“…Although our spectral resolution does not allow us to derive isotopic ratios, it is sufficient to detect and measure the prominent spectral features that define the carbon type by comparing our targets with those of known spectral standards presented by Barnbaum et al (1996) and using a number of the wellknown characteristic spectral features of each group presented in Walllerstein & Knapp (1998), Barnbaum et al (1996), Goswami (2005), Goswami et al (2010), Lloyd Evans (2010 and Totten & Irwin (2000).…”

Section: Spectral Types Of the New Objectsmentioning

confidence: 99%

“…A very strong depression of light below 5000 Å is a typical carbon star feature that only appears in the N-stars (Wallerstein & Knapp 1998;Lloyd Evans 2010), and Hα tends to be filled or in emission in most N-type stars (Gray & Corbally 2009). Inversely, early-type carbon stars show a relatively strong blue/violet continuum, but the spectra of C-R and CH-type stars are very similar (Barnbaum et al 1996;Goswami 2005;Goswami et al 2010).…”

Section: Spectral Types Of the New Objectsmentioning

confidence: 99%

“…Carbon (C) stars, objects with pronounced C 2 and CN molecular bands in their spectra (for a review of carbon stars, see Wallerstein & Knapp 1998;Lloyd Evans 2010) can be mainly divided into (i) intrinsic N-type stars and (ii) binary stars with one of the two components that has already passed through the AGB phase and pollutes its companion with C-rich material. Intrinsic N-type carbon stars are, in general, red, luminous, variable, and on the asymptotic giant branch (AGB), for which carbon is synthesized in the core and dredged up to the stellar surface.…”

Section: Introductionmentioning

confidence: 99%

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New carbon stars found in the Digitized First Byurakan Survey

Gigoyan¹,

Russeil²,

Mickaelian³

et al. 2012

A&A

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Faint high-latitude carbon stars (FHLCs) are distant, luminous giants. For this reason, they are often used to study the dynamical and chemical properties of the Galactic Halo. However, a more accurate investigation of photometric and spectroscopic surveys has revealed an increasing number of such objects with luminosities of main sequence stars. We report the first results of a systematic search of FHLCs using the Digitized First Byurakan Survey (DFBS) low-resolution spectral database. The DFBS low-resolution spectral plates are analysed to find new faint early and late-type carbon star candidates. Twenty new faint high-latitude carbon star candidates have been detected in an area of ∼4030 sq. deg. Moderate-resolution slit spectroscopy was carried out for all candidates, confirming the carbon star nature for thirteen of them (nine are new discoveries), while the remaining objects are M-type stars. The carbon star sample consists of five N-type carbon stars, for which the estimated mass-loss rates agree well with the typical ones found for such carbon stars; five comparatively bright CH-type carbon stars; and three are probably dwarf carbon (dC) stars. The distance determination indicates that the dC stars belong to the thin disk, while the other stars belong the Galactic halo. These results demonstrate that one can efficiently find new faint high-latitude carbon stars in the DFBS database.

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“…The AGB C stars in the Galactic disc have been known for a long time, are present in large quantity (several thousands) and are well documented (for reviews, see, e.g. Wallerstein & Knapp 1998;Lloyd Evans 2010). In contrast, their counterparts found in the halo are rare, with ∼150 objects, and their origin is not entirely clear.…”

Section: Introductionmentioning

confidence: 99%

Cool carbon stars in the halo and in dwarf galaxies: Hα, colours, and variability

Mauron

Gigoyan

Berlioz-Arthaud

et al. 2014

A&A

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The population of cool carbon (C) stars located far from the galactic plane is probably made of debris of small galaxies such as the Sagittarius dwarf spheroidal galaxy (Sgr), which are disrupted by the gravitational field of the Galaxy. We aim to know this population better through spectroscopy, 2MASS photometric colours, and variability data. When possible, we compared the halo results to C star populations in the Fornax dwarf spheroidal galaxy, Sgr, and the solar neighbourhood. We first present a few new discoveries of C stars in the halo and in Fornax. The number of spectra of halo C stars is now 125. Forty percent show Hα in emission. The narrow location in the JHK diagram of the halo C stars is found to differ from that of similar C stars in the above galaxies. The light curves of the Catalina and LINEAR variability databases were exploited to derive the pulsation periods of 66 halo C stars. A few supplementary periods were obtained with the TAROT telescopes. We confirm that the period distribution of the halo strongly resembles that of Fornax, and we found that it is very different from the C stars in the solar neighbourhood. There is a larger proportion of short-period Mira/SRa variables in the halo than in Sgr, but the survey for C stars in this dwarf galaxy is not complete, and the study of their variability needs to be continued to investigate the link between Sgr and the cool halo C stars.

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Carbon stars

Abstract: In this paper, the present state of knowledge of the carbon stars is discussed. Particular attention is given to issues of classification, evolution, variability, populations in our own and other galaxies, and circumstellar material.

Cited by 40 publications

References 267 publications

Characterizing the Population of Bright Infrared Sources in the Small Magellanic Cloud

Characterizing the Population of Bright Infrared Sources in the Small Magellanic Cloud

New carbon stars found in the Digitized First Byurakan Survey

Cool carbon stars in the halo and in dwarf galaxies: Hα, colours, and variability

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