399 citations · 2.9k across the 79 of their papers we have counts for
15 papers · 1 filter
A Time-Dependent Spectral Analysis of Cassiopeiae
Sean J. Gunderson, David P. Huenemoerder, José M. Torrejón +7
We investigated the temporal and spectral features of Cassiopeiae's X-ray emission within the context of the white dwarf accretion hypothesis. We find that the variabilities pr…
Observed epochal variations in X-ray lines from the O Supergiant Puppis do not require substantial changes in the wind mass flux
Sean J. Gunderson, Kenneth G. Gayley, David P. Huenemoerder +2
We fit the high resolution \textit{Chandra} X-ray spectra of the O supergiant Puppis using the variable boundary condition (VBC) line model to test the stability of its mass-lo…
Chandra/HETG Doppler velocity measurements in stellar coronal sources
E. Bozzo, D. P. Huenemoerder, M. Falanga +4
Stellar coronal sources have been observed in the past not only for their astrophysical interest in the field of binary system evolution and interaction, but also for their invalua…
A detailed analysis of X-ray emission line velocities of Capella from over 20 years of Chandra/HETG spectroscopy
E. Bozzo, D. P. Huenemoerder, N. Produit +3
Capella is the brightest chromospherically active binary in the sky, hosting a cooler G8III giant (Aa) and an hotter G1III companion (Ab). The source has been extensively observed…
Clumpy wind studies and the non-detection of cyclotron line in OAO 1657-415
Pragati Pradhan, Carlo Ferrigno, Biswajit Paul +11
Winds of massive stars are suspected to be inhomogeneous (or clumpy), which biases the measures of their mass loss rates. In High Mass X-ray Binaries (HMXBs), the compact object ca…
Testing the Reliability of X-rays as a Tool for Constraining Mass-loss Rates of Hot Stars
Sean J. Gunderson, Kenneth G. Gayley, Pragati Pradhan +2
We fit a new line shape model to \textit{Chandra} X-ray spectra of the O supergiant Puppis to test the robustness of mass-loss rates derived from X-ray wind line profiles again…
The Colliding Winds of WR 25 in High Resolution X-rays
Pragati Pradhan, David P. Huenemoerder, Richard Ignace +2
WR 25 is a colliding-wind binary star system comprised of a very massive O2.5If*/WN6 primary and an O-star secondary in a 208-day period eccentric orbit. These hot stars have stron…
Correlated X-ray and optical variability in the O-type supergiant zeta Puppis
Joy S. Nichols, Yael Naze, David P. Huenemoerder +11
Analysis of the recent long exposure Chandra X-ray observation of the early-type O star zeta Pup shows clear variability with a period previously reported in optical photometric st…
The clumpy absorber in the high-mass X-ray binary Vela X-1
V. Grinberg, N. Hell, I. El Mellah +13
Bright and eclipsing, the high-mass X-ray binary Vela X-1 offers a unique opportunity to study accretion onto a neutron star from clumpy winds of O/B stars and to disentangle the c…
A Coordinated X-ray and Optical Campaign of the Nearby Massive Binary Orionis Aa: II. X-ray Variability
J. S. Nichols, D. P. Huenemoerder, M. F. Corcoran +18
We present time-resolved and phase-resolved variability studies of an extensive X-ray high-resolution spectral dataset of the Orionis Aa binary system. The four observations, o…
Detailed X-Ray Line Properties of Theta2 Ori A in Quiescence
Arik W. Mitschang, Norbert S. Schulz, David P. Huenemoerder +2
We investigate X-ray emission properties of the peculiar X-ray source Theta2 Ori A in the Orion trapezium region using more than 500 ksec of HETGS spectral data in the quiescent st…
X-ray Flares of EV Lac: Statistics, Spectra, Diagnostics
David P. Huenemoerder, Norbert S. Schulz, Paola Testa +3
We study the spectral and temporal behavior of X-ray flares from the active M-dwarf EV Lac in 200 ks of exposure with the Chandra/HETGS. We derive flare parameters by fitting an em…
X-ray variation statistics and wind clumping in Vela X-1
Felix Fürst, Ingo Kreykenbohm, Katja Pottschmidt +8
We investigate the structure of the wind in the neutron star X-ray binary system Vela X-1 by analyzing its flaring behavior. Vela X-1 shows constant flaring, with some flares reach…
Structure and Evolution of Pre-Main Sequence Stars
Norbert S. Schulz, Glenn Allen, Mark W. Bautz +28
Low-mass pre-main sequence (PMS) stars are strong and variable X-ray emitters, as has been well established by EINSTEIN and ROSAT observatories. It was originally believed that thi…
Distribution and Structure of Matter in and around Galaxies
Norbert S. Schulz, Glenn Allen, Mark W. Bautz +24
Understanding the origins and distribution of matter in the Universe is one of the most important quests in physics and astronomy. Themes range from astro-particle physics to chemi…