K-H_2 Quasi-molecular absorption detected in the T-dwarf epsilon Indi Ba (2007)
Allard, France, Allard, Nicole F., Homeier, Derek, Kielkopf, John, McCaughrean, Mark J., Spiegelman, Fernand
T-type dwarfs present a broad and shallow absorption feature centred around 6950 A in the blue wing of the K doublet at 0.77 micron which resembles in depth and shape the satellite absorption...
Alkali Line Profiles in Ultracool White Dwarfs (2007)
Homeier, Derek, Allard, Nicole F., Johnas, Christine M. S., Hauschildt, Peter H., Allard, France
We present PHOENIX atmosphere models for metal-rich cool white dwarfs using improved line shapes for the Na I and K I resonance doublets. Profiles for collisional broadening due to H2 and He based on...
Alkali Line Profiles in Degenerate Dwarfs (2007)
Homeier, Derek, Allard, Nicole F., Allard, France
Ultracool stellar atmospheres show absorption by alkali resonance lines severely broadened by collisions with neutral perturbers. In the coolest and densest atmospheres, such as those of T dwarfs, Na...
Modelling Alkali Line Absorption and Molecular Bands in Cool DAZs (2005)
Homeier, Derek, Allard, Nicole F., Allard, France, Hauschildt, Peter H., Schweitzer, Andreas, Stancil, Phillip C., ...
Two peculiar stars showing an apparent extremely broadened and strong NaI D absorption have been discovered in surveys for cool white dwarfs by Oppenheimer et al. (2001) and Harris et al. (SDSS,...