- ID:
- ivo://CDS.VizieR/J/MNRAS/495/2858
- Title:
- Carbon stars as standard candles. I.
- Short Name:
- J/MNRAS/495/2858
- Date:
- 10 Dec 2021 11:55:33
- Publisher:
- CDS
- Description:
- 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 colour-selected carbon stars. We find the median absolute magnitude and the dispersion, in the J band, for the Large and the Small Magellanic Clouds (LMC/SMC) to be, respectively, (M_J_=-6.284+/-0.004 and {sigma}=0.352+/-0.005) and (M_J_=-6.160+/-0.015 and {sigma}=0.365+/-0.014). The difference between the MC may be explained by the lower metallicity of the SMC, 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 error-weighted mean C magnitude of the MC are equal. Thanks to the next generation of telescopes (JWST, ELT, and TMT), carbon stars could be detected in MC-type galaxies at distances out to 50-60Mpc. 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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Search Results
- ID:
- ivo://CDS.VizieR/III/140
- Title:
- Carbon stars from Baldone telescope
- Short Name:
- III/140
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue contains data on 318 cool carbon stars discovered on objective prism photographs taken with the Schmidt Telescope (80/120/240 cm) of the Radioastrophysical Observatory at Baldone near Riga. Green-yellow survey (BC Nos 1-217) is made on the ortochromatic astronomical films A-600. Reciprocial dispersion of the spectra: 600 A/mm or 1130 A/mm at H-gamma. The region of the sky covered by the survey: 1) 4.5 degrees wide zones centered on the galactic latitudes +7 and -7 degrees between longitudes 68 and 200 degrees, 2) equatorial zone at longitudes 84-96 degrees and 172-180 degrees, 3) several other separate fields with five degrees diameter. Infrared survey (BC Nos 218-318) made on the infrared Kodak plates 1N with the filter Schott RG1. Reciprocial dispersion: 2500 A/mm at the atmospheric A-band. The region of the sky covered: 1) 4.5 degrees wide zone centered on the galactic latitude +7 degrees between longitudes 128 and 140 degrees, 2) region between latitudes +9.5 and -9.5 degrees and longitudes between 80 and 96 degrees.
- ID:
- ivo://CDS.VizieR/J/AJ/93/663
- Title:
- Carbon stars from IRAS-LRS spectra
- Short Name:
- J/AJ/93/663
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The authors have classified 176 IRAS sources as carbon stars based on the presence of the SiC emission feature at 11.2 micron in their low-resolution spectra (LRS). Accurate positions were found by B. Skiff (Lowell Obs.), using visible-light (DSS), 2MASS, and WISE images to identify the carbon stars. Many of the stars are large-amplitude variables, whether designated or not, so sometimes the magnitudes are rounded to a whole magnitude so as to be representative of the brightness. Some notes are added about close companions and two stars where the existing position is significantly in error.
- ID:
- ivo://CDS.VizieR/J/ApJS/226/1
- Title:
- Carbon stars from LAMOST DR2 data
- Short Name:
- J/ApJS/226/1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we present the new catalog of carbon stars from the LAMOST DR2 catalog. In total, 894 carbon stars are identified from multiple line indices measured from the stellar spectra. We are able to identify the carbon stars by combining the CN bands in the red end with C_2_ and other lines. Moreover, we also classify the carbon stars into spectral sub-types of C-H, C-R, and C-N. These sub-types show distinct features in the multi-dimensional line indices, implying that in the future they can be used to identify carbon stars from larger spectroscopic data sets. While the C-N stars are clearly separated from the others in the line index space, we find no clear separation between the C-R and C-H sub-types. The C-R and C-H stars seem to smoothly transition from one to another. This may hint that the C-R and C-H stars may not be different in their origins, instead their spectra look different because of different metallicities. Due to the relatively low spectral resolution and lower signal-to-noise ratio, the ratio of ^12^C/^13^C is not measured and thus the C-J stars are not identified.
- ID:
- ivo://CDS.VizieR/J/ApJS/234/31
- Title:
- Carbon stars from LAMOST using machine learning
- Short Name:
- J/ApJS/234/31
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- In this work, we present a catalog of 2651 carbon stars from the fourth Data Release (DR4) of the Large Sky Area Multi-Object Fiber Spectroscopy Telescope (LAMOST). Using an efficient machine-learning algorithm, we find these stars from more than 7 million spectra. As a by-product, 17 carbon-enhanced metal- poor turnoff star candidates are also reported in this paper, and they are preliminarily identified by their atmospheric parameters. Except for 176 stars that could not be given spectral types, we classify the other 2475 carbon stars into five subtypes: 864 C-H, 226 C-R, 400 C-J, 266 C-N, and 719 barium stars based on a series of spectral features. Furthermore, we divide the C-J stars into three subtypes, C-J(H), C-J(R), and C-J(N), and about 90% of them are cool N-type stars as expected from previous literature. Besides spectroscopic classification, we also match these carbon stars to multiple broadband photometries. Using ultraviolet photometry data, we find that 25 carbon stars have FUV detections and that they are likely to be in binary systems with compact white dwarf companions.
- ID:
- ivo://CDS.VizieR/J/A+A/375/366
- Title:
- Carbon stars from the Hamburg/ESO survey
- Short Name:
- J/A+A/375/366
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalog contains 403 Faint High Latitude Carbon (FHLC) stars selected from the digitized objective prism plates of the Hamburg/ESO Survey (HES). Because of the ~15{AA} spectral resolution and high signal-to-noise ratio of the HES prism spectra, our automated procedure based on the detection of C_2_ and CN molecular bands permits high-confidence identification of carbon stars without the need for follow-up spectroscopy. 329 plates (87% of the survey) were examined, covering 6400deg^2^ to a magnitude limit of V~16.5. The catalog lists coordinates, photometry, and carbon band indices for 403 FHLC stars found in the Hamburg/ESO survey. B_J_ magnitudes are accurate to better than +/-0.2mag, including zero point errors. V magnitudes, B-V and U-B colors were derived by the procedure described in Christlieb et al. (2001A&A...366..898C). We also list an object classification for the sources, where "stars", "bright" and "ext" refer to point sources, sources above a saturation threshold, and sources detected as extended in DSS I images, respectively. We do not list V, B-V and U-B for saturated objects, because our color calibrations are not valid for them. Finally, we list two selection flags.
2737. Carbon stars in IC10
- ID:
- ivo://CDS.VizieR/J/A+A/424/125
- Title:
- Carbon stars in IC10
- Short Name:
- J/A+A/424/125
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present wide field CFH12K observations of the highly reddened Local Group galaxy IC 10. Using R,I,CN and TiO filters we identify 676 carbon stars in the field of IC 10. After mapping the reddening in the field, from the colours of the G dwarfs seen along the line of sight, we determine the mean apparent magnitude of the C star population to be <I_0_>=19.78, leading to a true modulus of (m-M)_0_=24.35+/-0.11 (741+/-37kpc). The old red giant stars define an asymmetric halo. With a halo diameter of at least 30', IC 10 is among the largest dwarfs of the Local Group. The surface density of C stars follows a radial power law with a scale length of 2.36', a value nearly identical to the scale length defined by the old giants thus IC 10 has a stellar halo where the old and intermediate-age populations are well mixed.
- ID:
- ivo://CDS.VizieR/J/A+AS/122/463
- Title:
- Carbon stars in Magellanic Clouds
- Short Name:
- J/A+AS/122/463
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 16 tables list the heliocentric and galactocentric radial velocities of several hundred carbon stars in the halo of the LMC and SMC. Most of them are newly discovered stars.
- ID:
- ivo://CDS.VizieR/J/MNRAS/453/2653
- Title:
- Carbon stars in the Galaxy and its satellites
- Short Name:
- J/MNRAS/453/2653
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We assemble 121 spectroscopically confirmed halo carbon stars, drawn from the literature, exhibiting measurable variability in the Catalina Surveys. We present their periods and amplitudes, which are used to estimate distances from period-luminosity relationships. The location of the carbon stars - and their velocities when available - allow us to trace the streams of the Sagittarius (Sgr) dwarf spheroidal galaxy. These are compared to a canonical numerical simulation of the accretion of Sgr. We find that the data match this model well for heliocentric distances of 15-50kpc, except for a virtual lack of carbon stars in the trailing arm just north of the Galactic plane, and there is only tentative evidence of the leading arm south of the plane. The majority of the sample can be attributed to the Sgr accretion. We also find groups of carbon stars which are not part of Sgr; most of which are associated with known halo substructures. A few have no obvious attribution and may indicate new substructure. We find evidence that there may be a structure behind the Sgr leading stream apocentre, at ~100kpc, and a more distant extension to the Pisces Overdensity also at ~100kpc. We study a further 75 carbon stars for which no good period data could be obtained, and for which NIR magnitudes and colours are used to estimate distances. These data add support for the features found at distances beyond 100kpc.
2740. Carbon stars IR emission
- ID:
- ivo://CDS.VizieR/J/A+A/330/505
- Title:
- Carbon stars IR emission
- Short Name:
- J/A+A/330/505
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Spectroscopic and photometric data relative to a sample of 55 carbon stars showing the 11.3{mu}m feature have been fitted in the wavelength range between 0.4 and 100{mu}m by means of a radiative transfer model using the laboratory extinction spectra of amorphous carbon and silicon carbide (SiC) grains. The transfer code allows to determine in a self-consistent way the grain equilibrium temperature of the various species at different distances from the central star and gives all the relevant circumstellar parameters which can be very important for the evolutionary study of carbon stars. In order to get meaningful information on the nature and physical properties of the dust grains responsible for the 11.3{mu}m feature and the underlying continuum, the fitting procedure of the spectr a has been applied individually to every single source. For this reason it has been possible to take into account any variation in position and shape of the band from source to source. Our analysis show that all the sources, in addition to the amorphous carbon grains accounting for the continuum emission, need always the presence of {alpha}-SiC particles while some of them require also {beta}-SiC. Moreover, the presence of one or both types of SiC particles seems not correlated neither with the total optical thickness nor with any other physical and geometrical parameters of the circumstellar envelope. The best-fit parameters found in this work have been used to calculate the mass-loss rate from the central stars. The clear correlation, that we find between the strength of the SiC feature and the total mass loss-rate, confirms the results already found by other authors for the same kind of sources and derived from the observed CO emission lines.
