Browsing University of Hertfordshire by Author "Gallardo, J."

Now showing items 1-5 of 5

    • Discovery of a T dwarf + white dwarf binary system 

      Day-Jones, Avril; Pinfield, D.J.; Ruiz, M.; Beaumont, H.; Burningham, B.; Gallardo, J.; Gianninas, A.; Bergeron, P.; Napiwotzki, Ralf; Jenkins, J.S.; Zhang, Z.H.; Murray, D.N.; Catalan, Silvia; Ines Gomes, Joana (2011)
      We present the discovery of the first T dwarf + white dwarf binary system LSPM 1459+0857 AB, confirmed through common proper motion and spectroscopy. The white dwarf is a high proper motion object from the LSPM catalogue ...

    • Discovery of the first L dwarf plus giant binary system and eight other ultracool dwarfs in wide binaries 

      Zhang, Z.; Pinfield, D.J.; Day-Jones, A.C.; Burningham, B.; Jones, H.R.A.; Yu, S.; Jenkins, J.S.; Han, Z.; Galvez-Ortiz, M.C.; Gallardo, J.; Garcia Perez, A.E.; Weights, D.; Tinney, C.G.; Pokorny, R.S. (2010)
      We identify 806 ultracool dwarfs (of which 34 are newly discovered L dwarfs) from their Sloan Digital Sky Survey (SDSS) riz photometry and obtain proper motions through cross-matching with the United Kingdom Infrared ...

    • Discovery of the first white dwarf + T dwarf binary system and the use of white dwarfs as age calibrators 

      Day-Jones, Avril; Pinfield, D.J.; Ruiz, M.; Beaumont, H.; Gallardo, J.; Gianninas, A.; Bergeron, P.; Napiwotzki, Ralf; Jenkins, J.S.; Burningham, B.; Zhang, Z.H.; Jones, H.R.A.; Murray, D.; Catalan, Silvia; Ines Gomes, Joana (American Institute of Physics (AIP), 2010)
      We present the discovery of the first white dwarf + T dwarf binary system. Systems containing a white dwarf and a brown dwarf are rare but can be used to place constraints on the age of the binary, making them valuable ...

    • Rotational velocities for M dwarfs 

      Jenkins, J.S.; Ramsey, L.; Jones, H.R.A.; Pavlenko, Y.; Gallardo, J.; Barnes, J.R.; Pinfield, D.J. (2009)
      We present spectroscopic rotation velocities (v sin i) for 56 M dwarf stars using high-resolution Hobby-Eberly Telescope High Resolution Spectrograph red spectroscopy. In addition, we have also determined photometric ...

    • The sub-stellar birth rate from UKIDSS 

      Day-Jones, A. C.; Marocco, F.; Pinfield, D.J.; Zhang, Z. H.; Burningham, B.; Deacon, Niall; Ruiz, M. T.; Gallardo, J.; Jones, H.R.A.; Lucas, P.W.; Jenkins, J. S.; Gomes, J.; Folkes, S. L.; Clarke, J. R. A. (2013-04)
      We present a new sample of mid-L to mid-T dwarfs with effective temperatures of 11001700 K selected from the UKIDSS Large Area Survey (LAS) and confirmed with infrared spectra from X-shooter/Very Large Telescope. This ...