Angular Momentum Loss and Stellar spin-down in Magnetic Massive Stars (2008)
Ud-Doula, Asif, Owocki, Stanley P., Townsend, Richard H. D.
We examine the angular momentum loss and associated rotational spin-down for magnetic hot stars with a line-driven stellar wind and a rotation-aligned dipole magnetic field. Our analysis here is...
Ud-Doula, Asif, Owocki, Stanley P., Townsend, Richard H. D.
We examine the angular momentum loss and associated rotational spindown for magnetic hot stars with a line-driven stellar wind and a rotation-aligned dipole magnetic field. Our analysis here is based...
The B and Be star population of NGC 3766 (2008)
McSwain, M. Virginia, Huang, Wenjin, Gies, Douglas R., Grundstrom, Erika D., Townsend, Richard H.D.
We present multiple epochs of Hα spectroscopy for 47 members of the open cluster NGC 3766 to investigate the long-term variability of its Be stars. Sixteen of the stars in this sample are Be stars,...
Quantitative analysis of resolved X-ray emission line profiles of O stars (2007)
Cohen, David H., Leutenegger, Maurice A., Townsend, Richard H. D.
By quantitatively fitting simple emission line profile models that include both atomic opacity and porosity to the Chandra X-ray spectrum of $\zeta$ Pup, we are able to explore the trade-offs between...
The B and Be Star Population of NGC 3766 (2007)
McSwain, M. Virginia, Huang, Wenjin, Gies, Douglas R., Grundstrom, Erika D., Townsend, Richard H. D.
We present multiple epochs of H-alpha spectroscopy for 47 members of the open cluster NGC 3766 to investigate the long term variability of its Be stars. Sixteen of the stars in this sample are Be...
Smith, Nathan, Townsend, Richard H. D.
We present a semi-analytic model for shaping the nebula around eta Carinae that accounts for the simultaneous production of bipolar lobes and an equatorial disk through a rotating surface explosion....
Chandra HETGS Multi-Phase Spectroscopy of the Young Magnetic O Star theta^1 Orionis C (2005)
Gagne, Marc, Oksala, Mary E., Cohen, David H., Tonnesen, Stephanie K., Ud-Doula, Asif, Owocki, Stanley P., ...
We report on four Chandra grating observations of the oblique magnetic rotator theta^1 Ori C (O5.5 V) covering a wide range of viewing angles with respect to the star's 1060 G dipole magnetic field....
Diagnostics of Disks Around Hot Stars (2004)
Cohen, David H., Hanson, Margaret M., Townsend, Richard H. D., Bjorkman, Karen S., Gagné, Marc
We discuss three different observational diagnostics related to disks around hot stars: absorption line determinations of rotational velocities of Be stars; polarization diagnostics of circumstellar...
Be-star rotation: how close to critical? (2003)
Townsend, Richard H. D., Owocki, Stanley P., Howarth, Ian D.
We argue that, in general, observational studies of Be-star rotation have paid insufficient attention to the effects of equatorial gravity darkening. We present new line-profile calculations that...