399 citations · 2.9k across the 79 of their papers we have counts for
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Heating in an Extended Accretion Disk Corona along the Z-Pattern in Cyg X-2
N. S. Schulz, D. P. Huenemoerder, L. Ji +3
We observed at very high spectral resolution the prototype Z-source Cyg x-2 twice along its entire X-ray spectral variation pattern. In this preliminary analysis we find an extende…
X-ray Emission from Young Stellar Objects in the εChamaeleontis Group: the Herbig Ae Star HD 104237 and Associated Low-Mass Stars
Paola Testa, David P. Huenemoerder, Norbert S. Schulz +1
We present Chandra-HETGS observations of the Herbig Ae star HD 104237 and the associated young stars comprising lower mass stars, in the 0.15-1.75\msol mass range, in their pre-mai…
Geometry Diagnostics of a Stellar Flare from Fluorescent X-rays
P. Testa, J. J. Drake, B. Ercolano +5
We present evidence of Fe fluorescent emission in the Chandra HETGS spectrum of the single G-type giant HR 9024 during a large flare. In analogy to solar X-ray observations, we int…
Evidence for Accretion in the High-resolution X-ray Spectrum of the T Tauri Star System Hen 3-600
David P. Huenemoerder, Joel H. Kastner, Paola Testa +2
We present high-resolution X-ray spectra of the multiple T Tauri star system Hen 3-600, obtained with the High Energy Transmission Grating Spectrograph on the Chandra X-ray Observa…
On X-ray Optical Depth in the Coronae of Active Stars
Paola Testa, Jeremy J. Drake, Giovanni Peres +1
We have investigated the optical thickness of the coronal plasma through the analysis of high-resolution X-ray spectra of a large sample of active stars observed with the High Ener…
Detailed diagnostics of an X-ray flare in the single giant HR 9024
Paola Testa, Fabio Reale, David Garcia-Alvarez +1
We analyze a 96 ks Chandra/HETGS observation of the single G-type giant HR 9024. The high flux allows us to examine spectral line and continuum diagnostics at high temporal resolut…
X-ray Variability in the Young Massive Triple theta2 Ori A
Norbert S. Schulz, Paola Testa, David P. Huenemoerder +2
Massive stars rarely show intrinsic X-ray variability. The only O-stars credited to be intrinsically variable are theta1 Ori C due to effects from magnetic confinement of its wind,…
X-ray Spectroscopy of the Contact Binary VW Cephei
David P. Huenemoerder, Paola Testa, Derek L. Buzasi
Short-period binaries represent extreme cases in the generation of stellar coronae via a rotational dynamo. Such stars are important for probing the origin and nature of coronae in…
Chandra/HETGS Observations of the Capella System: the Primary as a Dominating X-ray Source
Kazunori Ishibashi, Daniel Dewey, David P. Huenemoerder +1
Using the Chandra/High Energy Transmission Grating Spectrometer (hereafter HETGS) we have detected Doppler motion of Capella's X-ray emission lines in the 6 -- 25AA wave-band. The…
Star Formation in the Era of the Three Great Observatories
Scott J. Wolk, Norbert Schulz, John Stauffer +6
This paper summarizes contributions and suggestions as presented at the Chandra Workshop Star Formation in the Era of Three Great Observatories conducted in July 2005. One of the d…
X-ray flare modeling in the single giant HR 9024
Paola Testa, David Garcia-Alvarez, Fabio Reale +1
We analyze a Chandra-HETGS observation of the single G-type giant HR 9024. The high flux allows us to examine spectral line and continuum diagnostics at high temporal resolution, t…
The Chandra High Energy Transmission Grating: Design, Fabrication, Ground Calibration and Five Years in Flight
Claude R. Canizares, John E. Davis, Daniel Dewey +11
Details of the design, fabrication, ground and flight calibration of the High Energy Transmission Grating, HETG, on the Chandra X-ray Observatory are presented after five years of…
An Assessment of the Fe XVIII and Fe XIX Line Ratios from the Chandra Grating Observations of Capella
P. Desai, N. S. Brickhouse, J. J. Drake +8
Observations of Fe XVIII and Fe XIX X-ray, EUV, and FUV line emission, formed at the peak of Capella's (alpha Aurigae) emission measure distribution and ubiquitous in spectra of ma…
HETGS Spectroscopy of a Coronally Active Contact Binary, VW Cep
David P. Huenemoerder, Adrienne Hunacek
Short-period binaries represent extreme cases in the generation of stellar coronae via a rotational dynamo. Such stars are important for probing the origin and nature of coronae in…
Variation in Emission and Absorption Lines and Continuum Flux by Orbital Phase in Vela X-1
Greg Goldstein, David P. Huenemoerder, David Blank
High resolution spectral studies were undertaken at orbital phases 0, 0.25 and 0.5 on the high-mass X-ray binary (HMXB) Vela X-1 using archival Chandra data. We present (a) the fir…
Chandra X-ray Observatory High-resolution X-ray Spectroscopy of Stars: Modeling and Interpretation
David P. Huenemoerder
The Chandra X-ray Observatory grating spectrometers allow study of stellar spectra at resolutions on the order of 1000. Prior x-ray observatories' low resolution data have shown th…
The Coronal X-ray Spectrum of the Multiple Weak-Lined T Tauri Star System HD 98800
Joel H. Kastner, David P. Huenemoerder, Norbert S. Schulz +3
We present high-resolution X-ray spectra of the multiple (hierarchical quadruple) weak-lined T Tauri star system HD 98800, obtained with the High Energy Transmission Gratings Spect…
Stellar Coronal Spectroscopy with the Chandra HETGS
David P. Huenemoerder, Bram Boroson, Norbert S. Schulz +4
Spectroscopy with the Chandra High Energy Transmission Grating Spectrometer provides details on X-ray emission and activity from young and cool stars through resolution of emission…
Modeling the NeIX Triplet Spectral Region of Capella with the Chandra and XMM-Newton Gratings
Jan-Uwe Ness
High resolution X-ray spectroscopy with the diffraction gratings of Chandra and XMM-Newton offers new chances to study a large variety of stellar coronal phenomena. A popular X-ray…
The Coronae of AR Lac
David P. Huenemoerder, Claude R. Canizares, Jeremy J. Drake +1
We observed the coronally active eclipsing binary, AR Lac, with the High Energy Transmission Grating on Chandra for a total of 97 ks, spaced over five orbits, at quadratures and co…
X-ray Modeling of Very Young Early Type Stars in the Orion Trapezium: Signatures of Magnetically Confined Plasmas and Evolutionary Implications
Norbert S. Schulz, Claude R. Canizares, Dave P. Huenemoerder +1
We analyzed high resolution X-ray spectra in the wavelength range of 1.5 -- 25 A of three of its X-ray brightest members obtained with the High Energy Transmission Grating Spectrom…
Evidence for Accretion: High-Resolution X-ray Spectroscopy of the Classical T Tauri Star TW Hydrae
Joel H. Kastner, David P. Huenemoerder, Norbert S. Schulz +2
We present high resolution X-ray spectra of the X-ray bright classical T Tauri star, TW Hydrae, covering the wavelength range of 1.5-25 AA. The differential emission measure derive…
X-Ray Plasma Diagnostics of Stellar Winds in Young Massive Stars
N. S. Schulz, C. R. Canizares, D. P. Huenemoerder +2
High resolution X-ray spectra of very young massive stars opened a new chapter in the diagnostics and understanding of the properties of stellar wind plasmas. Observations of sever…
X-ray Spectra and Light Curves of AR Lac: Temperature Structure, Abundances, and Variability
David Huenemoerder, Claude Canizares, Kevin Tibbetts
We observed AR Lac, an eclipsing RS CVn binary star, with the Chandra High Energy Grating Spectrometer for a total of 100 ks divided into six intervals covering both quadratures an…