Piotr M. Kowalski

Spitzer Observations of the Oldest White Dwarfs in the Solar Neighborhood (2009)

Kilic, Mukremin, Kowalski, Piotr M., Reach, William T., Von Hippel, Ted

We present Spitzer 5-15 μm spectroscopy of one cool white dwarf and 3.6-8 μm photometry of 51 cool white dwarfs with T_(eff) < 6000 K. The majority of our targets have accurate BVRIJHK photometry...

Spitzer Observations of the Oldest White Dwarfs in the Solar Neighborhood (2009)

Kilic, Mukremin, Kowalski, Piotr M., Reach, William T., Von Hippel, Ted

We present Spitzer 5-15 micron spectroscopy of one cool white dwarf and 3.6-8 micron photometry of 51 cool white dwarfs with T_eff < 6000 K. The majority of our targets have accurate BVRIJHK...

Composition, structure, and stability of the rutile TiO_2(110) surface: oxygen depletion, hydroxylation, hydrogen migration and water adsorption (2009)

Kowalski, Piotr M., Meyer, Bernd, Marx, Dominik

A comprehensive phase diagram of lowest-energy structures and compositions of the rutile TiO_2(110) surface in equilibrium with a surrounding gas phase at finite temperatures and pressures has been...

The first mid-infrared spectra of cool white dwarfs (2008)

Kilic, Mukremin, Kowalski, Piotr M., Mullally, Fergal, Reach, William T., Von Hippel, Ted

We present the first mid-infrared spectra of two cool white dwarfs obtained with the Spitzer Space Telescope. We also present 3.5-8 µm photometry for 19 cool white dwarfs with 5000 K ≤ T-eff ≤...

A Nearby Old Halo White Dwarf Candidate from the Sloan Digital Sky Survey (2008)

Hall, Patrick B., Kowalski, Piotr M., Harris, Hugh C., Awal, Akshay, Leggett, S. K., Kilic, Mukremin, ...

We report the discovery of a nearby, old, halo white dwarf candidate from the Sloan Digital Sky Survey. SDSS J110217.48+411315.4 has a proper motion of 1.75 arcsec/year and redder optical colors than...

The First Mid-Infrared Spectra of Cool White Dwarfs (2007)

Kilic, Mukremin, Kowalski, Piotr M., Mullally, Fergal, Reach, William T., Von Hippel, Ted

We present the first mid-infrared spectra of two cool white dwarfs obtained with the Spitzer Space Telescope. We also present 3.5-8 micron photometry for 19 cool white dwarfs with 5000K < Teff <...

White dwarf atmosphere models with Ly-$\alpha$ opacity in the analysis of the white dwarf cooling sequence of NGC 6397 (2007)

Kowalski, Piotr M.

We discuss the importance of pure hydrogen white dwarf atmosphere models with Ly-$\rm \alpha$ far red wing opacity in the analysis of the white dwarf cooling sequence of the globular cluster NGC...

The Pseudo-continuum Bound-free Opacity of Hydrogen and its Importance in Cool White Dwarf Atmospheres (2006)

Kowalski, Piotr M.

We investigate the importance of the pseudo-continuum bound-free opacity from hydrogen atoms in the atmospheres of cool white dwarfs. This source of absorption, when calculated by the occupation...

On the Dissociation Equilibrium of H2 in Very Cool, Helium-Rich White Dwarf Atmospheres (2005)

Kowalski, Piotr M.

We investigate the dissociation equilibrium of $\rm H_2$ in very cool, helium-rich white dwarf atmospheres. We present the solution of the non-ideal chemical equilibrium for the dissociation of...