Search Publications
Magnetic flux cancellation associated with a recurring solar jet observed with Hinode, RHESSI, and STEREO/EUVI
Young, P. R.; Mason, H. E.; Krucker, S. +7 more
Aims: We study the physical properties of a recurring solar active region jet observed in X-rays and extreme-ultraviolet (EUV).
Methods: Multi-wavelength data from all three instruments on board Hinode were analysed. X-ray imaging and spectroscopy of the microflaring emission associated with the jets was performed with the Reuven Ramaty High E…
The weak magnetic field of the O9.7 supergiant ζOrionisA
Bouret, J. -C.; Martins, F.; Donati, J. -F. +4 more
We report here the detection of a weak magnetic field of 50-100G on the O9.7 supergiant ζOrionisA (ζOriA), using spectropolarimetric observations obtained with NARVAL at the 2-m Télescope Bernard Lyot atop Pic du Midi (France). ζOriA is the third O star known to host a magnetic field (along with θ1OriC and HD191612), and the first detec…
Do All Flares Have White-Light Emission?
Mathioudakis, M.; Keenan, F. P.; Jess, D. B. +1 more
High-cadence, multiwavelength optical observations of a solar active region (NOAA AR 10969), obtained with the Swedish Solar Telescope, are presented. Difference imaging of white light continuum data reveals a white-light brightening, 2 minutes in duration, linked to a cotemporal and cospatial C2.0 flare event. The flare kernel observed in the whi…
The red clump absolute magnitude based on revised Hipparcos parallaxes
Groenewegen, M. A. T.
Context: Over the past decade the use of the red clump (RC) as distance indicator has increased in importance as this evolutionary phase is well populated and a good local calibration exists.
Aims: The absolute calibration of the RC in the I and K band is investigated again based on the recently published revised Hipparcos parallaxes.
Meth…
Open Clusters as Galactic Disk Tracers. I. Project Motivation, Cluster Membership, and Bulk Three-Dimensional Kinematics
Majewski, Steven R.; Frinchaboy, Peter M.
We have begun a survey of the chemical and dynamical properties of the Milky Way disk as traced by open star clusters. In this first contribution, the general goals of our survey are outlined and the strengths and limitations of using star clusters as a Galactic disk tracer sample are discussed. We also present medium-resolution (R ~ 15, 0000) spe…
Statistical analysis of plasmaspheric plumes with Cluster/WHISPER observations
de Keyser, J.; Décréau, P. M. E.; Vallières, X. +2 more
Plasmaspheric plumes have been routinely observed by the four Cluster spacecraft. This paper presents a statistical analysis of plumes observed during five years (from 1 February 2001 to 1 February 2006) based on four-point measurements of the plasmasphere (outside 4 Earth radii) as it is sampled by the spacecraft in a narrow local time sector bef…
Proplyds and Massive Disks in the Orion Nebula Cluster Imaged with CARMA and SMA
Carpenter, John M.; Wilner, D.; Eisner, J. A. +3 more
We imaged a 2' × 2' region of the Orion Nebula Cluster (ONC) in 1.3 mm wavelength continuum emission with the recently commissioned Combined Array for Research in Millimeter Astronomy (CARMA) and with the Submillimeter Array (SMA). Our mosaics include >250 known near-IR cluster members, of which 36 are so-called ``proplyds…
The development of new solar indices for use in thermospheric density modeling
Tobiska, W. Kent; Bouwer, S. Dave; Bowman, Bruce R.
New solar indices have been developed to improve thermospheric density modeling for research and operational purposes. Out of 11 new and 4 legacy indices and proxies, we have selected 3 (F10.7, S10.7, and M10.7) for use in the new JB2006 empirical thermospheric density model. In this work, we report on the development of these solar irradiance ind…
Derivation of density and temperature from the Cassini Huygens CAPS electron spectrometer
André, N.; Lewis, G. R.; Coates, A. J. +4 more
In this paper we present two methods to derive electron fluid parameters from the CAPS-ELS spectrometer on board the Cassini spacecraft currently in orbit around Saturn. In the first part of the paper we give a basic overview of the instrument and describe the challenges inherent in the derivation of density and temperature values using these tech…
The Persistence of Memory, or How the X-Ray Spectrum of SNR 0509-67.5 Reveals the Brightness of Its Parent Type Ia Supernova
Hughes, John P.; Badenes, Carles; Bravo, Eduardo +1 more
We examine the dynamics and X-ray spectrum of the young Type Ia supernova remnant 0509-67.5 in the context of the recent results obtained from the optical spectroscopy of its light echo. Our goal is to estimate the kinetic energy of the supernova explosion using Chandra and XMM-Newton observations of the supernova remnant, thus placing the birth e…