- ID:
- ivo://CDS.VizieR/J/other/RAA/15.1671
- Title:
- New carbon stars from LAMOST survey
- Short Name:
- J/other/RAA/15.1
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Carbon stars are excellent kinematic tracers of galaxies and can serve as a viable standard candle, so it is worthwhile to automatically search for them in a large amount of spectra. In this paper, we apply the efficient manifold ranking algorithm to search for carbon stars from the Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) pilot survey, whose performance and robustness are verified comprehensively with four test experiments. Using this algorithm, we find a total of 183 carbon stars, and 158 of them are new findings. According to different spectral features, our carbon stars are classified as 58 C-H stars, 11 C-H star candidates, 56 C-R stars, ten C-R star candidates, 30 C-N stars, three C-N star candidates, and four C-J stars. There are also ten objects which have no spectral type because of low spectral quality, and a composite spectrum consisting of a white dwarf and a carbon star. Applying the support vector machine algorithm, we obtain the linear optimum classification plane in the J-H versus H-Ks color diagram which can be used to distinguish C-H from C-N stars with their J-H and H-Ks colors. In addition, we identify 18 dwarf carbon stars with their relatively high proper motions, and find three carbon stars with FUV detections likely have optical invisible companions by cross matching with data from the Galaxy Evolution Explorer. In the end, we detect four variable carbon stars with the Northern Sky Variability Survey, the Catalina Sky Survey and the LINEAR variability databases. According to their periods and amplitudes derived by fitting light curves with a sinusoidal function, three of them are likely semiregular variable stars and one is likely a Mira variable star.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+AS/122/489
- Title:
- New infrared carbon stars in IRAS PSC
- Short Name:
- J/A+AS/122/489
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present new results of a search for infrared carbon stars (IRCS) based on the combination of IRAS and near infrared colours. A sample of 207 stars with IRAS colours that characterize IRCS is selected and measured in the JHKL photometric bands. Using a [12-25] vs. K-L colour diagram, 20 new IRCS candidates are proposed. Medium resolution spectra in the ~6000-9000{AA} range of 8 of these candidates confirm their carbon rich nature. In addition we propose a few stars with LRS class "4n" as oxygen-rich candidates, and a few stars with LRS classes "0n" and "1n" as carbon-rich.
- ID:
- ivo://CDS.VizieR/J/A+A/635/A14
- Title:
- New R Coronae Borealis stars
- Short Name:
- J/A+A/635/A14
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This catalogue contains 2356 entries. It was created to list targets of interest that have similar near- and mid-infrared characteristics than R Coronae Borealis (RCB) stars which are hydrogen-deficient carbon-rich supergiant stars known to possess warm circumstellar shells. It is therefore a catalogue enriched in such objects and further spectroscopic follow-ups are needed to reveal the true nature of each target. The catalogue was produced from a series of selection criteria on the infrared colours and brightness of sources published in the WISE All-Sky data release, and also listed in the 2MASS catalogue. These sources spread over the entire sky. The selection criteria are described in section 2 of the paper.
- ID:
- ivo://CDS.VizieR/J/A+A/537/A108
- Title:
- NGC 6822 AGB spectroscopic catalogue
- Short Name:
- J/A+A/537/A108
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We calibrate spectroscopically the C- versus (vs.) M-type asymptotic giant branch (AGB) star selection made using near-IR photometry, and investigate the spatial distribution of the C/M ratio in NGC 6822, based on low resolution spectroscopy and near-IR photometry.
- ID:
- ivo://CDS.VizieR/J/ApJ/658/1203
- Title:
- Nitrogen-enhanced metal-poor stars
- Short Name:
- J/ApJ/658/1203
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Theoretical models of very metal-poor intermediate-mass asymptotic giant branch (AGB) stars predict a large overabundance of primary nitrogen. The very metal-poor, carbon-enhanced, s-process-rich stars, which are thought to be the polluted companions of now extinct AGB stars, provide direct tests of the predictions of these models. Recent studies of the carbon and nitrogen abundances in metal-poor stars have focused on the most carbon-rich stars, leading to a potential selection bias against stars that have been polluted by AGB stars that produced large amounts of nitrogen and hence have small [C/N] ratios. We call these stars nitrogen-enhanced metal-poor (NEMP) stars and define them as having [N/Fe]>+0.5 and [C/N]<-0.5. In this paper we report on the [C/N] abundances of a sample of 21 carbon-enhanced stars, all but three of which have [C/Fe]<+2.0. If NEMP stars were made as easily as carbon-enhanced metal-poor (CEMP) stars, then we expected to find between two and seven NEMP stars. Instead, we found no NEMP stars in our sample.
- ID:
- ivo://CDS.VizieR/J/A+A/439/559
- Title:
- OGLE eclipsing binaries (bulge+lmc+smc)
- Short Name:
- J/A+A/439/559
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 222000 I-band light curves of variable stars detected by the OGLE-II survey (ftp://bulge.princeton.edu/ogle/ogle2/bulge_dia_variables) in the direction of the Galactic Bulge have been searched for eclipsing binaries (EBs). A previously developed code to analyze lightcurve shapes and identify long period variables (LPVs) has been adapted to identify EBs. The parameters in the modified code have been optimised to recover a list of about 140 detached EBs in the Small Magellanic Cloud previously identified in the literature as particularly well suited for distance estimates (and which have periods more than 0.85 days). The power of the code is demonstrated by identifying 16 and 178 previously uncatalogued EBs in the SMC and LMC, respectively. Among the 222 000 variable stars in the direction of the Galactic Bulge 3053 EBs have been identified. Periods and phased lightcurves are presented.
- ID:
- ivo://CDS.VizieR/J/A+A/425/595
- Title:
- OGLE+2MASS+DENIS LPV in Magellanic Clouds
- Short Name:
- J/A+A/425/595
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The 68000 I-band light curves of variable stars detected by the OGLE survey (ftp://sirius.astrouw.edu.pl/ogle/ogle2/clusters) in the Large and Small Magellanic Clouds (MCs) are fitted by Fourier series, and also correlated with the DENIS (<II/228>) and 2MASS All-Sky Release (<II/246>) databases and with lists of spectroscopically confirmed M-, S- and C-stars. Lightcurves and the results of the lightcurve fitting (periods and amplitudes) and DENIS and 2MASS magnitudes are presented for 2277 M-,S-,C-stars in the MCs.
- ID:
- ivo://CDS.VizieR/J/other/Ap/64.27
- Title:
- Periodic variables in Catalina and LINEAR
- Short Name:
- J/other/Ap/64.27
- Date:
- 22 Feb 2022
- Publisher:
- CDS
- Description:
- In this study we continue spectral class determinations for large number of optically faint periodic variables taken from the Catalina Surveys Data Release 1 (CSDR1)and LINEAR data sets. Spectral classes and physical parameters are presented for 1184 periodic variables with periods P>=10 days, taken from modern large sky area spectroscopic and photometric databases, including LAMOST(Large Sky Area Multi-Object Fiber Spectroscopic Telescope), SDSS(Sloan Digital Sky Survey), the Hamburg Quasar Survey(HQS)m the Hamburg /ESO Survey (HES), and Gaia Data Release 2 (DR2). In Gaia DR2 catalogue, luminosities are presented for 276 objects and radial velocities (RV) for 108. Spectral classes were confirmed for more than 650 objects. The majority of the variables are found to be F, G, K, M dwarfs and giants, a few dozen carbon (C) stars (N-type Asymptotic Giant Branch (AGB) stars), and a few S stars. Some periodic variables are blue objects, such as B and A stars. The periods are in the range 10<=P<=1504 days and Catalina magnitudes in range 11.5<=V<=20.0mag. Finding new and faint evolved AGB stars in the halo of our Galaxy is the first priority. A catalogue containing multi-parameter data for 1184 periodic variables from modern astronomical databases has been generated.
- ID:
- ivo://CDS.VizieR/J/A+A/568/A100
- Title:
- Photometric monitoring of halo C stars
- Short Name:
- J/A+A/568/A100
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Carbon stars are among the brightest intermediate-age stars. They are seen in nearly all galaxies of the Local Group. In the Milky Way they are members of the thin disk but over a hundred have been identified in the Galactic halo. Since the halo consists essentially of an old stellar population, these carbon stars warrant special attention. We believe that such stars are trespassers and belong to streams left over by disrupted dwarf spheroidal galaxies. By performing photometric monitoring we intend to identify Miras among the halo carbon stars. We obtained, over several semesters, K and J images centered on the carbon stars in order to determine their variation and periodicity.
- ID:
- ivo://CDS.VizieR/J/A+A/403/93
- Title:
- Photometry of AGB stars in NGC 185 and NGC 147
- Short Name:
- J/A+A/403/93
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The tables represent results of an ongoing photometric survey of Local Group galaxies, using a four filter technique based on the method of Wing (1971, Proc. of the Conference on Late-Type Stars, ed. G.W. Lockwood and H.M. Dyck, KPNO Contribution 554, 145) to identify and characterise the late-type stellar content. Two narrow band filters centred on spectral features of TiO and CN allow us to distinguish between AGB stars of different chemistries [M-type (O-rich) and C-type (C-rich)]. The major parts of two dwarf galaxies, NGC 185 and NGC 147, were observed; 154 new AGB carbon stars in NGC 185 and 146 in NGC 147 were identified. All detected stars (called sample 1 in the paper) are included in the tables, with coordinates and photometric properties. All stars of sample 1 have photometry in the filters V and i. For all stars, which are in addition included in the smaller sample 2 (and have also photometry in the narrowband filters TiO and CN) the colour index (TiO-CN) is provided, too. In the tables a chemistry flag F marks in which classification group the star falls. All stars of sample 2 can have "c" for Carbon star, "o" for oxygen-rich M-type star or "r" for the rest. This correspond to the selection areas in Figure 4 of the paper. The flag for all stars of sample 1, which are not already included in sample 2 (only Vi-photometry) is "u" for unclassified.
