- ID:
- ivo://CDS.VizieR/J/A+A/574/A56
- Title:
- IRC +10216 17.8GHz-26.3GHz spectrum
- Short Name:
- J/A+A/574/A56
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- IRC +10216 is the prototypical carbon star exhibiting an extended molecular circumstellar envelope. Its spectral properties are therefore the template for an entire class of objects. The main goal is to systematically study the 1.3cm spectral line characteristics of IRC +10216. We carried out a spectral line survey with the Effelsberg-100m telescope toward IRC +10216. It covers the frequency range between 17.8GHz and 26.3GHz (K-band). In the circumstellar shell of IRC +10216, we find 78 spectral lines, among which 12 remain unidentified. The identified lines are assigned to 18 different molecules and radicals. A total of 23 lines from species known to exist in this envelope are detected for the first time outside the Solar System and there are additional 20 lines firstly detected in IRC +10216. The potential orgin of U lines is also discussed. Assuming local thermodynamic equilibrium (LTE), we determine rotational temperatures and column densities of 17 detected molecules. Molecular abundances relative to H_2_ are also estimated. A non-LTE analysis of NH_3_ shows that the bulk of its emission arises from the inner envelope with a kinetic temperature of 70+/-20K. Evidence for NH_3_ emitting gas with higher kinetic temperature is also obtained, and potential abundance differences between various ^13^C-bearing isotopologues of HC_5_N are evaluated. Overall, the isotopic ^12^C/^13^C ratio is estimated to be 49+/-9. Finally, a comparison of detected molecules in the 1.3cm range with the dark cloud TMC-1 indicates that silicate bearing molecules are more predominant in IRC +10216.
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Search Results
- ID:
- ivo://CDS.VizieR/J/A+A/606/A74
- Title:
- IRC +10216 13.3GHz-18.5GHz spectrum
- Short Name:
- J/A+A/606/A74
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- A spectral line survey of IRC +10216 between 13.3 and 18.5GHz was carried out using the Shanghai Tian Ma 65 m Radio Telescope (TMRT-65m) with a sensitivity of <7mK. Thirty-five spectral lines of 12 different molecules and radicals were detected in total. Except for SiS, the detected molecules are all carbon-chain molecules, including HC_3_N, HC_5_N, HC_7_N, HC_9_N, C_6_H, C_6_H^-^, C_8_H, SiC_2_, SiC_4_, c-C_3_H_2_, and l-C_5_H. The presence of rich carbon-bearing molecules is consistent with the identity of IRC +10216 as a carbon-rich asymptotic giant branch (AGB) star. The excitation temperatures and column densities of the observed species are derived by assuming a local thermodynamic equilibrium and homogeneous conditions.
- ID:
- ivo://CDS.VizieR/J/PAZh/25/860
- Title:
- IR photometry of three carbon stars
- Short Name:
- J/PAZh/25/860
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- JHKLM photometry of three carbon stars - two symbiotic stars (UV Aur and NQ Gem) and the unique object RW LMi(= CIT-6) - which were obtained in 1983-1999 is presented.
- ID:
- ivo://CDS.VizieR/J/PASP/117/199
- Title:
- IRTS carbon stars
- Short Name:
- J/PASP/117/199
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We have identified 139 cool carbon stars in the near-infrared spectrophotometric survey of the Infrared Telescope in Space (IRTS) from the conspicuous presence of molecular absorption bands at 1.8, 3.1, and 3.8{mu}m. Among them, 14 are new bright (K~4.0-7.0) Carbon stars. We find a trend relating the 3.1{mu}m band strength to the (K-L') color index, which is known to correlate with mass-loss rate. This could be an effect of a relation between the depth of the 3.1{mu}m feature and the degree of development of the extended stellar atmosphere where dust starts to form.
- ID:
- ivo://CDS.VizieR/J/PAZh/30/605
- Title:
- JHKLM photometry for carbon stars
- Short Name:
- J/PAZh/30/605
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- JHKLM photometry for nine carbon Mira stars, 18 carbon semiregular variables and 2 oxygen Mira stars are provided.
- ID:
- ivo://CDS.VizieR/J/A+AS/101/513
- Title:
- JHKLM photometry of C stars
- Short Name:
- J/A+AS/101/513
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- We present J H K L M photometry for 25 Carbon stars, and 450, 600, 800 and 1100 {mu}m for 12 carbon stars and the S-star W Aql. Carbon stars reside on a different part of the [12-25], [K-L] diagram than O-rich stars. Our work confirms earlier observations and shows this relation to hold up at least [K-L] ~ 8mag.
- ID:
- ivo://CDS.VizieR/J/A+A/227/82
- Title:
- JHKLM photometry of 'IRAS-discovered' stars
- Short Name:
- J/A+A/227/82
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- This paper presents results of JHKLM photometry data analysis of 249 southern 'IRAS-discovered' stars, which exhibit an emission feature at 11.3 microns in their low-resolution spectra (class 4n stars). The method of Epchtein et al. (1987A&AS...71...39E) is used to separate oxygen-rich and carbon-rich stars on the basis of their sole NIR and IRAS broad-band fluxes. It is shown that NIR data are necessary to calculate the total IR energy received from IRAS stars and such fundamental parameters as individual mass loss rates. An evolutionary model is developed to match the sequence of stars in color diagrams. It is suggested that the sequence of increasing optical depths might not be an evolutionary sequence, but would rather reflect the termination of a process in which the near-IR index increases very quickly at the beginning and is strongly dependent on the mass loss rate.
- ID:
- ivo://CDS.VizieR/J/A+A/445/69
- Title:
- JHK' photometry of C stars in NGC 147
- Short Name:
- J/A+A/445/69
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- Near-infrared J, H and K' images were used to investigate the stellar contents of the asymptotic giant branch (AGB) population in the nearby dwarf elliptical galaxy NGC 147. The obtained (K,J-K) and (K,H-K) color-magnitude diagrams contain stars of AGB and red giant branch populations, where the former consists of a group of bright blue stars, a dominant population of M giant and a red C star population.We identified 91 AGB C stars in NGC 147 with the mean absolute magnitude and colors of <M_K_>=-7.56, <(J-K)_0_>=1.81 and <(H-K)_0_>=0.74. The estimated number ratio of C stars to M giant stars (C/M) is 0.16+/-0.02. The estimated local C/M ratios of 0.14+/-0.02 for the inner region (r<70") and 0.19+/-0.03 for the outer region (r>70") indicate a weak radial gradient. The mean bolometric magnitude of 91 C stars in NGC 147 is <M_bol_>=-4.32+/-0.49. The bolometric luminosity function of M giant stars in NGC 147 extends up to M_bol_=-5.8 magnitude, and that of only C stars spans -5.6<M_bol_<-3.5. The color histograms of AGB stars in (J-K) and (H-K) show a main peak containing M giant stars, a red tail containing C stars with a weak excess, and a blue excess possibly due to bright blue foreground stars and AGB stars younger than M giants. The comparison of the theoretical isochrone models with the color distribution and the brightness of AGB stars indicates that most of the bright M giants in NGC 147 were formed at log(t_yr_)~8.4 with a range of 8.2~8.6. Ages of the majority of M giant stars in NGC 147 are similar to those of younger M giant stars in its companion NGC 185, while their formation occurred more recently than the older M giant stars in NGC 185 by ~2Gyrs.
- ID:
- ivo://CDS.VizieR/J/A+A/456/905
- Title:
- JKs, i'g'r' photometry of C stars in NGC 6822
- Short Name:
- J/A+A/456/905
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- From a 2{deg}x2{deg} survey of NGC 6822 we have previously established that this Local Group dwarf irregular galaxy possesses a huge spheroid having more than one degree in length. This spheroid is in rotation but its rotation curve is known only within ~15' from the center. It is therefore critical to identify bright stars belonging to the spheroid to characterize, as far as possible, its outer kinematics. We use the new wide field near infrared imager CPAPIR, operated by the SMARTS consortium, to acquire J, K_s_ images of two 34.8'x34.8' areas in the outer spheroid to search for C stars. The colour diagram of the fields allows the identification of 192 C stars candidates but a study of the FWHM of the images permits the rejection of numerous non-stellar objects with colours similar to C stars. We are left with 75 new C stars, their mean K_s_ magnitude and mean colour are similar to the bulk of known NGC 6822 C stars. This outer spheroid survey confirms that the intermediate-age AGB stars are a major contributor to the stellar populations of the spheroid. The discovery of some 50 C stars well beyond the limit of the previously known rotation curve calls for a promising spectroscopic follow-up to a major axis distance of 40'.
- ID:
- ivo://CDS.VizieR/J/A+A/474/35
- Title:
- JKs photometry of C stars in IC10 and WLM
- Short Name:
- J/A+A/474/35
- Date:
- 21 Oct 2021
- Publisher:
- CDS
- Description:
- The selection of AGB C and M stars from NIR colours has been done in recent years using adjustable criteria that are in needs of standardization if one wants to compare, in a coherent manner, properties of various populations. We intend to assess the NIR colour technique to identify C and M stars. We compare the NIR colours of several C stars previously identified from spectroscopy or narrow band techniques in WLM, IC 10 and NGC 6822. We demonstrate that very few M stars have (J-K)_0_>1.4 but a non negligible number of C stars are bluer than this limit. Thus, counts of M and C stars based on such limit do not produce pure samples. C/M ratios determined from NIR colours must be regarded as underestimates mainly because the M numbers include many warm C stars and also K stars if no blue limit is considered.
