Now showing items 1-9 of 9

    • 70 DA white dwarfs identified in LAMOST pilot survey 

      Luo, A.L.; Oswalt, Terry D.; Zhao, J.K.; Zhao, G. (2013-06)
      We present a spectroscopically identified catalog of 70 DA white dwarfs (WDs) from the LAMOST pilot survey. Thirty-five are found to be new identifications after cross-correlation with the Eisenstein et al. and Villanova ...
    • The chromospheric activity, age, metallicity, and space motions of 36 wide binaries 

      Zhao, Jingkun; Oswalt, Terry D.; Rudkin, Mark J.; Zhao, Gang; Chen, Yuqin (2011-02-14)
      We present the chromospheric activity (CA) levels, metallicities, and full space motions for 41 F, G, K, and M dwarf stars in 36 wide binary systems. Thirty-one of the binaries contain a white dwarf (WD) component. In such ...
    • A determination of the local density of white dwarf stars 

      Holberg, Jay B.; Oswalt, Terry D.; Sión, Edward M. (2002)
      The most recent version of the Catalog of Spectroscopically Identified White Dwarfs lists 2249 white dwarf stars. Among these stars are 109 white dwarfs that have either reliable trigonometric parallaxes or color-based ...
    • Fragile binary candidates in the SDSS DR8 spectroscopic archive 

      Zhao, J.K; Oswalt, Terry D.; Zhao, G. (2012-02)
      We present a catalog of 80 very wide fragile binary candidates (projected separations >10,000 AU) from the Sloan Digital Sky Survey Data Release Eight spectral archive. The pairs were selected based on proper motion, radial ...
    • LP 400-22, a Very Low Mass and High-Velocity White Dwarf 

      Kawka, Adéla; Vennes, Stéphane; Oswalt, Terry D.; Smith, J. Allyn; Silvestri, Nicole M. (2006-03-08)
      We report the identification of LP 400-22 (WD 2234+222) as a very low mass and high-velocity white dwarf. The ultraviolet GALEX and optical photometric colors and a spectral line analysis of LP 400-22 show this star to ...
    • Multi-site photometry of the pulsating Herbig Ae star V346 Ori 

      Oswalt, Terry D.; Bernabei, S.; Ripepi, V.; Ruoppo, A.; Marconi, M.; Monteiro, M. J. P. F. G.; Rodriguez, E.; Leccia, S.; Palla, F.; Catanzaro, G. (2009-04-16)
      Context. The study of pulsation in pre-main-sequence intermediate-mass stars represents an important tool for deriving information about fundamental stellar parameters and internal structure, as well as testing theoretical ...
    • Observational constraints on the degenerate mass-radius relation 

      Holberg, Jay B.; Oswalt, Terry D.; Barstow, M. A. (2012-02-09)
      The white dwarf mass-radius relationship is fundamental to modern astrophysics. It is central to routine estimation of DA white dwarf masses derived from spectroscopic temperatures and gravities. It is also the basis for ...
    • Tracers of chromospheric structure.I. Ca ii H&K emission distribution of 13,000 F, G, and K stars in SDSS DR7 spectroscopic sample 

      Zhao, J.K.; Oswalt, Terry D.; Lu, Q.H.; Luo, A.L.; Zhang, L.Y.; Zhao, G. (2013-05)
      We present chromospheric activity index SHK measurements for over 13,000 F, G, and K disk stars with high signal-to-noise ratio (>60) spectra in the Sloan Digital Sky Survey (SDSS) Data Release 7 (DR7) spectroscopic sample. ...
    • The white dwarfs within 25 pc of the sun: Kinematics and spectroscopic subtypes 

      Sión, Edward M.; Holberg, Jay B.; Oswalt, Terry D.; McCook, George P.; Wasatonic, Richard P.; Myszka, Janine (2014-05-01)
      We present the fractional distribution of spectroscopic subtypes, range and distribution of surface temperatures, and kinematical properties of the white dwarfs (WDs) within 25 pc of the Sun. There is no convincing evidence ...