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      Permanent link:
      https://www.ias.ac.in/article/fulltext/joaa/042/0077

    • Keywords

       

      Stars: individual: HIP 19265; HIP 88580; Capella; HIP 23309; stars: coronae; X-rays: stars.

    • Abstract

       

      We present observations of four bright stars observed with the AstroSat Soft X-ray Telescope (SXT). Visible light from bright stars like these can leak through the very thin filter in front of the CCD in the focal plane CCD camera of the SXT and thus making the extraction of X-ray events difficult. Here, we showhow to extract the X-ray events without contamination by the visible light. The procedure applied to four bright stars here demonstrates how reliable X-ray information can be derived in such cases. The sample of bright stars studied here consists of two A spectral types (HIP 19265, HIP 88580), one G/K giant (Capella), and a nearby M-type dwarf (HIP 23309). No X-ray emission is observed from the A-type stars, as expected. X-ray spectra of Capella and HIP 23309 are derived and modeled here, and compared with the previous X-ray observations of these stars to show the reliability of the method used. We find that optical light can start to leak in the very soft energy bands below 0.5 keV for stars with $V= 8$ mag. In the process, we present the first X-ray spectrum of HIP 23309.

    • Author Affiliations

       

      K. P. SINGH1 G. STEWART2 S. CHANDRA3 G. C. DEWANGAN4,4 S. BHATTACHARYYA5 N. S. KAMBLE5 S. VISHWAKARMA5 J. G. KOYANDE5

      1. Indian Institute of Science Education and Research Mohali, Sector 81, P.O. Manauli, SAS Nagar 140 306, India.
      2. Department of Physics and Astronomy, The University of Leicester, University Road, Leicester LE1 7RH, UK.
      3. Center for Space Research, North-West University, Potchefstroom 2520, South Africa.
      4. Inter-University Centre for Astronomy and Astrophysics, Ganeshkhind, Pune 411 007, India
      5. Department of Astronomy and Astrophysics, Tata Institute of Fundamental Research, Homi Bhabha Road, Mumbai 400 005, India.

    • Dates

       
      Published
      17 July 2021
      Manuscript received
      5 November 2020
      Accepted
      4 December 2020
      Final version published online
      17 July 2021

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