High-Resolution Chandra Spectroscopy of τ Scorpii: A Narrow-Line X-Ray Spectrum from a Hot Star

  title={High-Resolution Chandra Spectroscopy of $\tau$ Scorpii: A Narrow-Line X-Ray Spectrum from a Hot Star},
  author={David H Cohen and Genevi{\`e}ve E. de Messi{\`e}res and J. J. Macfarlane and Nathan A. Miller and Joseph Patrick Cassinelli and Stanley P. Owocki and Duane A. Liedahl},
  journal={The Astrophysical Journal},
Long known to be an unusual early-type star by virtue of its hard and strong X-ray emission, τ Scorpii poses a severe challenge to the standard picture of O-star wind-shock X-ray emission. The Chandra HETGS spectrum now provides significant direct evidence that this B0.2 star does not fit this standard wind-shock framework. The many emission lines detected with the Chandra gratings are significantly narrower than what would be expected from a star with the known wind properties of τ Sco… 
High-Resolution Chandra Spectroscopy of γ Cassiopeiae (B0.5e)
γ Cas is the prototypical classical B0.5e star and is now known to be the primary in a wide binary system. It has long been famous for its unique hard X-ray characteristics, among which are
Chandra spectroscopy of the hot star β Crucis and the discovery of a pre-main-sequence companion
In order to test the O star wind-shock scenario for X-ray production in less luminous stars with weaker winds, we made a pointed 74-ks observation of the nearby early B giant, β Crucis (β Cru; B0.5
gamma Cassiopeiae: an X-ray Be star with personality
An exciting unsolved problem in the study of high energy processes of early type stars concerns the physical mechanism for producing X-rays near the Be starγ Cassiopeiae. By now we know that this
High-Resolution Chandra X-Ray Imaging and Spectroscopy of the σ Orionis Cluster
We present results of a 90 ks Chandra X-ray observation of the young ? Orionis cluster ( -->age ~ 3 Myr ) obtained with the HETGS. We use the high-resolution grating spectrum and moderate-resolution
Detailed X-ray line properties of θ² Ori A in quiescence
We investigate X-ray emission properties of the peculiar X-ray source θ2 Ori A in the Orion Trapezium region using more than 500 ks of HETGS spectral data in the quiescent state. The amount of
Extraordinarily Hot X-Ray Emission from the O9 Emission-Line Star HD 119682
We present new optical and X-ray observations to show that the X-ray source 1WGA J1346.5-6255 previously associated with the SNR G309.2-0.6 can be unequivocally identified with the emission-line star
Wind signatures in the X-ray emission-line profiles of the late-O supergiant ζ Orionis
X-ray line-profile analysis has proved to be the most direct diagnostic of the kinematics and spatial distribution of the very hot plasma around O stars. The Doppler-broadened line profiles provide
X-Ray Modeling of Very Young Early-Type Stars in the Orion Trapezium: Signatures of Magnetically Confined Plasmas and Evolutionary Implications
The Orion Trapezium is one of the youngest and closest star-forming regions within our Galaxy. With a dynamic age of ~3 × 105 yr, it harbors a number of very young hot stars, which likely are on the
High-resolution X-ray spectroscopy ofθ Carinae
Context. The peculiar hot starθ Car in the open cluster IC 2602 is a blue straggler as well as a single-line binary of short period (2.2d). Aims. Its high-energy properties are not well known, though
A Multiphase Suzaku Study of X-rays from τ Sco
We obtained relatively high signal-to-noise X-ray spectral data of the early massive star τ Sco (B0.2V) with the Suzaku X-ray Imaging Spectrometer (XIS) instrument. This source displays several


ASCA X-Ray Spectroscopy of the Unusual B0 V Star τ Scorpii
We have obtained a high-quality ASCA spectrum of the MK standard B0 V star τ Sco in order to test the standard wind-shock picture of OB star X-ray production. The fluxes in three line complexes from
New Challenges for Wind Shock Models: The Chandra Spectrum of the Hot Star δ Orionis
The Chandra spectrum ofOri A shows emission lines from hydrogen- and helium-like states of Si, Mg, Ne, and O, along with Nvii Lyand lines from ions in the range Fe xvii-Fexxi. In contrast to the
High resolution X-ray spectroscopy of $\zeta$ Puppis with the XMM-Newton reflection grating spectrometer
We present the rst high resolution X-ray spectrum of the bright O4Ief supergiant star Puppis, obtained with the Reflection Grating Spectrometer on-board XMM-Newton. The spectrum exhibits bright
Stagnation and Infall of Dense Clumps in the Stellar Wind of τ Scorpii
Observations of the B0.2 V star q Scorpii have revealed unusual stellar wind characteristics: redshifted absorption in the far-ultraviolet O VI resonance doublet up to D)250 km s~1 and extremely hard
Chandra Observations of Variable Embedded X-ray sources in Orion. Paper I: Resolving Orion Trapezium
We used the High Energy Transmission Grating Spectrometer (HETGS) onboard the Chandra X-ray Observatory to perform two observations, separated by three weeks, of the Orion Trapezium region. The
ROSAT PSPC Observations of 27 Near-Main-Sequence B Stars
In this paper, we report on ROSAT Position Sensitive Proportional Counter (PSPC) observations of 27 near-main-sequence B stars made with unprecedented sensitivity. Contrary to the results of previous
The effects of coronal regions on the X-ray flux and ionization conditions in the winds of OB supergiants and Of stars.
The anomalously strong O VI and N V lines in O stars and the C IV lines in B supergiants may be due to Auger ionization by X-rays from a thin coronal zone at the base of the cool stellar winds. We
X-ray induced ionization in the winds of near-main-sequence O and B stars
We investigate the effects of X-rays on the ionization state of stellar winds for O and early-B stars along the main sequence. In our investigation, detailed statistical equilibrium, radiative
The magnetic field and wind confinement of θ1 Orionis C
We report the detection, through spectropolarimetric observations, of a strong dipolar magnetic field of presumably fossil origin at the surface of the very young O star theta (1) Ori C. The Stokes V
The magnetic field and wind confinement of beta Cephei: new clues for interpreting the Be phenomenon?
In this paper, we use the very recent spectropolarimetric observations of β Cep collected by Henrichs et al. and propose for this star a consistent model of the large-scale magnetic field and of the