Browsing by Author "Pavlenko, Ya V."

Now showing items 1-4 of 4

    • A detailed study of Lithium in 107 CHEPS dwarf stars 

      Pavlenko, Ya V.; Jenkins, J. S.; Ivanyuk, O. M.; Jones, Hugh; Kaminsky, B. M.; Lyubchik, Yu. P.; Yakovina, L. A. (2018-03-20)
      Context. We report results from lithium abundance determinations using high resolution spectral analysis of the 107 metal-rich stars from the Calan-Hertfordshire Extrasolar Planet Search programme. Aims. We aim to set out ...

    • Primeval very low-mass stars and brown dwarfs -- II. The most metal-poor substellar object 

      Zhang, Z. H.; Homeier, D.; Pinfield, David; Lodieu, N.; Jones, Hugh; Allard, F.; Pavlenko, Ya V. (2017-06-01)
      SDSS J010448.46+153501.8 has previously been classified as an sdM9.5 subdwarf. However, it's very blue J-K colour (-0.15+/-0.17) suggests a much lower metallicity compared to normal sdM9.5 subdwarfs. Here we re-classify ...

    • A spectroscopic and proper motion search of Sloan Digital Sky Survey : red subdwarfs in binary systems 

      Zhang, Z. H.; Pinfield, D.J.; Burningham, B.; Jones, H.R.A.; Galvez-Ortiz, M. C.; Catalan, S.; Smart, R. L.; Lepine, S.; Clarke, J. R. A.; Pavlenko, Ya V.; Murray, D. N.; Kuznetsov, M. K.; Day-Jones, A. C.; Gomes, J.; Marocco, F.; Sipocz, B. (2013-09)
      Red subdwarfs in binary systems are crucial for both model calibration and spectral classification. We search for red subdwarfs in binary systems from a sample of high proper motion objects with Sloan Digital Sky Survey ...

    • Surprisingly different starspot distributions on the near equal-mass equal-rotation-rate stars in the M dwarf binary GJ 65 AB 

      Barnes, J. R.; Jeffers, S. V.; Haswell, C. A.; Jones, H. R. A.; Shulyak, D.; Pavlenko, Ya V.; Jenkins, J. S. (2017-10-11)
      We aim to understand how stellar parameters such as mass and rotation impact the distribution of starspots on the stellar surface. To this purpose, we have used Doppler imaging to reconstruct the surface brightness ...