Search Publications
α TrA Junior
Ayres, Thomas R.; Harper, Graham M.; Brown, Alexander
The ``hybrid chromosphere'' star α Trianguli Australis (K2 Ib-IIa) displays atypical coronal properties for its class: elevated soft X-ray emission, flare outbursts, and a superhot (T~10 MK) spectrum. The Wide Field Planetary Camera 2 (WFPC2) on board the Hubble Space Telescope (HST) now has found a faint object close to the red supergiant, 0.4" n…
Imaging Spectroscopy of a Gradual Hardening Flare on 2000 November 25
Masuda, Satoshi; Nakajima, Hiroshi; Yokoyama, Takaaki +5 more
We present an examination of multiwavelength observations of an M8.2 long-duration flare which occurred on 2000 November 25. During the flare, we can see a hard X-ray (HXR) source on one Hα flare ribbon in the HXR images obtained with the Hard X-ray Telescope aboard Yohkoh, and a compact microwave emission source on the other flare ribbon in the d…
The Effect of Proton Temperature Anisotropy on the Electron Heat Flux Dissipation in Solar Coronal Holes
Markovskii, S. A.
A possible source of the ion cyclotron waves that energize the protons in the fast solar wind is the electron heat flux launched by reconnection events at the base of coronal holes. A strong enough heat flux becomes unstable and generates cyclotron waves that interact with the protons. When the protons are energized via the cyclotron resonance, th…
Identification of a Peculiar Radio Source in the Aftermath of Large Coronal Mass Ejection Events
Vourlidas, Angelos; Démoulin, Pascal; Hoang, Sang +1 more
We report the discovery of a new radio feature associated with coronal mass ejection (CME) events. The feature is a low-frequency (<1 MHz), relatively wide (~300 kHz) continuum that appears just after the main phase of the eruptive event, lasts for several hours, and exhibits a slow negative frequency drift. So far, we have identified this radi…
Evidence for Deuterium Astration in the Planetary Nebula Sh 2-216?
Rauch, Thomas; Chayer, Pierre; Kruk, Jeffrey W. +2 more
We present FUSE observations of the line of sight to WD 0439+466 (LS V +46 21), the central star of the old planetary nebula Sh 2-216. The FUSE data show absorption by many interstellar and stellar lines, in particular D I, H2 (J=0-9), HD J=0-1, and CO. Many other stellar and ISM lines are detected in the STIS E140M HST spectra of this …
Dynamical Parameters for AM 0644-741
Antunes, Alex; Wallin, John
We present a simulation match to the 2004 Hubble Heritage high-resolution optical images of AM 0644-741. In N-body/smoothed particle hydrodynamics (SPH) simulations of AM 0644-741, we recreate the star formation features, as well as the underlying kinematics. Our simulations contain sufficient numerical density to accurately distinguish the overla…
Extraction of Halo Coronal Mass Ejection Asymmetry Information from LASCO Coronagraph Images
Webb, D. F.; Ling, A. G.
A method for quantifying the asymmetry attributes of coronal mass ejections (CMEs) is described. The technique developed is applied to a set of full-halo CMEs observed from 1997 to the end of 2000 by the Large Angle Spectrometric Coronagraph (LASCO) instrument on board the Solar and Heliospheric Observatory (SOHO) spacecraft. A cross section of ev…
Diffusive Compression Acceleration of Energetic Particles with an Application to Shock Acceleration near Injection Energies
Zhang, Ming
The behavior of energetic charged particles accelerated by a continuous plasma compression profile is explored in the framework of diffusion. At high enough energies, the accelerated particles have a power-law spectrum with a slope generally steeper than a shock spectrum with the same compression ratio. The spectral slope depends on the ratio of t…
Erratum: ``A Potential Supernova Remnant-X-Ray Binary Association in M31'' (ApJ, 634, 365 [2005])
Williams, Benjamin F.; Kong, Albert K. H.; Kolb, U. +3 more
We have discovered a flaw in the light curves we previously generated using the XMM-Newton Science Analysis Software (SAS), which can produce spurious Type A power density spectra (R. Barnard et al. 2007, preprints astro-ph/0610035, astro-ph/0703120). This is the type of variability associated with disk-accreting binary systems (R. Barnard et al. …
Ultra-Low-Frequency Solar He II 30.4 nm Pulsations
Didkovsky, L.; Judge, D. L.; Gangopadhyay, P. +2 more
Solar EUV and X-ray measurements from the Charge, Element and Isotope Analysis System/Solar EUV Monitor (CELIAS/SEM) on board Solar and Heliospheric Observatory (SOHO) and the Geostationary Operational Environmental Satellites (GOES) have been studied for four time periods. Two ultra-low-frequency CELIAS/SEM He II 30.4 nm pulsations were observed …