{
  "id": "2401.04955",
  "version": "v1",
  "published": "2024-01-10T06:45:26.000Z",
  "updated": "2024-01-10T06:45:26.000Z",
  "title": "Classification and characterization using HCT/HFOSC spectra of carbon stars selected from the HES survey",
  "authors": [
    "Meenakshi Purandardas",
    "Aruna Goswami"
  ],
  "comment": "Accepted for publication in the journal Astrophysics and Space Science",
  "categories": [
    "astro-ph.SR",
    "astro-ph.GA"
  ],
  "abstract": "We present results from the analysis of 88 carbon stars selected from Hamburg/ESO (HES) survey using low-resolution spectra (R$\\sim$1330 \\& 2190). The spectra were obtained with the Himalayan Faint Object Spectrograph Camera (HFOSC) attached to the 2-m Himalayan Chandra Telescope (HCT). Using a well-defined spectral criteria based on the strength of carbon molecular bands, the stars are classified into different groups. In our sample, we have identified 53 CH stars, four C-R stars, and two C-N type stars. Twenty-nine stars could not be classified due to the absence of prominent C$_{2}$ molecular bands in their spectra. We could derive the atmospheric parameters for 36 stars. The surface temperature is determined using photometric calibrations and synthesis of the H-alpha line profile. The surface gravity log g estimates are obtained using parallax estimates from the Gaia DR3 database whenever possible. Microturbulent velocity ($\\zeta$) is derived using calibration equation of log g \\& ${\\zeta}$. We could determine metallicity for 48 objects from near-infrared Ca II triplet features using calibration equations. The derived metallicity ranges from $-$0.43$\\leq$[Fe/H]$\\leq$$-$3.49. Nineteen objects are found to be metal-poor ([Fe/H] $\\leq$$-$1), 14 very metal-poor ([Fe/H]$\\leq$$-$2), and five extremely metal-poor ([Fe/H]$\\leq$$-$3.0) stars. Eleven objects are found to have a metallicity in the range $-$0.43 $\\leq$[Fe/H]$\\leq$$-$0.97. We could derive the carbon abundance for 25 objects using the spectrum synthesis calculation of the C$_{2}$ band around 5165\\AA. The most metal-poor objects found will make important targets for follow-up detailed chemical composition studies based on high-resolution spectroscopy, that are likely to provide insight into the Galactic chemical evolution.",
  "revisions": [
    {
      "version": "v1",
      "updated": "2024-01-10T06:45:26.000Z"
    }
  ],
  "analyses": {
    "keywords": [
      "carbon stars",
      "hct/hfosc spectra",
      "detailed chemical composition studies",
      "himalayan faint object spectrograph camera",
      "classification"
    ],
    "note": {
      "typesetting": "TeX",
      "pages": 0,
      "language": "en",
      "license": "arXiv",
      "status": "editable"
    }
  }
}