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Global Axisymmetric Magnetorotational Instability With Density Gradients
(2008-05)
We examine global incompressible axisymmetric perturbations of a differentially rotating MHD plasma with radial density gradients. It is shown that the standard magnetorotational instability (MRI) criterion drawn from the ...
SDSS J142625.71+575218.3: the First Pulsating White Dwarf With A Large Detectable Magnetic Field
(2008-08)
We report the discovery of a strong magnetic field in the unique pulsating carbon- atmosphere white dwarf SDSS J142625.71 + 575218.3. From spectra gathered at the MMT and Keck telescopes, we infer a surface field of B(s) ...
Limits On Planets Around Pulsating White Dwarf Stars
(2008-03)
We present limits on planetary companions to pulsating white dwarf stars. A subset of these stars exhibit extreme stability in the period and phase of some of their pulsation modes; a planet can be detected around such a ...
A New ZZ Ceti White Dwarf Pulsator: G30-20
(2002-11)
We report the discovery of a new hydrogen atmosphere variable white dwarf (DAV; ZZ Ceti), G30-20, a high-amplitude, long-period pulsator. The Fourier transform of its light curve shows power around 1050-1125 s. We suspect ...
White Dwarf Luminosity And Mass Functions From Sloan Digital Sky Survey Spectra
(2008-01)
We present the first phase in our ongoing work to use Sloan Digital Sky Survey (SDSS) data to create separate white dwarf (WD) luminosity functions (LFs) for two or more different mass ranges. In this paper, we determine ...
The Century Survey Galactic Halo Project. III. A Complete 4300 Deg(2) Survey Of Blue Horizontal Branch Stars In The Metal-Weak Thick Disk And Inner Halo
(2008-02)
We present a complete spectroscopic survey of 2414 2MASS-selected blue horizontal branch ( BHB) candidates selected over 4300 deg(2) of the sky. We identify 655 BHB stars in this non-kinematically selected sample. We ...
A "Starless'' Core That Isn't: Detection of A Source in the L1014 Dense Core With the Spitzer Space Telescope
(2004-09)
We present observations of L1014, a dense core in the Cygnus region previously thought to be starless, but data from the Spitzer Space Telescope show the presence of an embedded source. We propose a model for this source ...
The Mid-Infrared Extinction Law In The Ophiuchus, Perseus, And Serpens Molecular Clouds
(2009-01)
We compute the mid-IR extinction law from 3.6 to 24 mu m in three molecular clouds-Ophiuchus, Perseus, and Serpens-by combining data from the "Cores to Disks" Spitzer Legacy Science program with deep JHK(s) imaging. Using ...
The Dust Cloud Around The White Dwarf G 29-38. II. Spectrum From 5 To 40 Mu M And Mid-Infrared Photometric Variability
(2009-03)
We model the mineralogy and distribution of dust around the white dwarf G29-39 using the infrared spectrum from 1 to 35 mu m. The spectral model for G29-38 dust combines a wide range of materials based on spectral studies ...
A Young-Planet Search in Visible and Infrared Light: Dn Tauri, V836 Tauri, and V827 Tauri
(2008-11)
In searches for low-mass companions to late-type stars, correlation between radial velocity variations and line bisector slope changes indicates contamination by large starspots. Two young stars demonstrate that this test ...