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The System Parameters of DW Ursae Majoris
Knigge, C.; Dhillon, V. S.; Szkody, P. +8 more
We present new constraints on the system parameters of the SW Sextantis star DW Ursae Majoris, based on ultraviolet (UV) eclipse observations with the Hubble Space Telescope. Our data were obtained during a low state of the system, in which the UV light was dominated by the hot white dwarf (WD) primary. The duration of the WD eclipse allows us to …
Deuterium toward Two Milky Way Disk Stars: Probing Extended Sight Lines with the Far Ultraviolet Spectroscopic Explorer
Hoopes, Charles G.; Sembach, Kenneth R.; Hébrard, Guillaume +2 more
We have carried out an investigation of the abundance of deuterium along two extended sight lines through the interstellar medium (ISM) of the Galactic disk. The data include Far Ultraviolet Spectroscopic Explorer (FUSE) observations of HD 195965 (B1 Ib) and HD 191877 (B0 V), as well as Space Telescope Imaging Spectrograph (STIS) observations of H…
The Early Ultraviolet Evolution of the ONeMg Nova V382 Velorum 1999
Gehrz, Robert D.; Bond, Howard E.; Krautter, Joachim +7 more
We present a multiwavelength study of the ONeMg Galactic nova V382 Velorum 1999 using HST/STIS and FUSE ultraviolet spectra and comparisons with published ground-based optical spectra. We find a close match to the basic phenomenology of another well-studied ONeMg nova, V1974 Cygni (Nova Cyg 1992), in particular, to the spectral development through…
Transit Target Selection Using Reduced Proper Motions
Gould, Andrew; Morgan, Christopher W.
In searches for planetary transits in the field, well over half of the survey stars are typically giants or other stars that are too large to permit straightforward detection of planets. For all-sky searches of bright V<~11 stars, the fraction is ~90%. We show that the great majority of these contaminants can be removed from the sample by analy…
Coronal Structure of a Flaring Region and Associated Coronal Mass Ejection
Kundu, M. R.; Manoharan, P. K.
We report the multiwavelength investigations of an eruptive flare event that occurred on 2001 April 2 at about 11 UT. The manifestations associated with this flare event have been studied from the near-Sun region to about 0.5 AU. The Hα images from the Meudon Spectroheliograph reveal a fast spectacular eruption of plasmoids from the flare site to …
The Evolution of Vector Magnetic Fields in an Emerging Flux Region
Kubo, M.; Lites, B. W.; Shimizu, T.
Collaborative observations of NOAA Active Region 9231 were carried out during 9 days in 2000 November using the Advanced Stokes Polarimeter (ASP), Yohkoh/SXT, TRACE, and SOHO/MDI, in order to record the evolution of the photospheric magnetic field and its related coronal response. During this period an emerging flux region (EFR) appeared in the ph…
The origin of the Fe K features in Markarian 205 and Markarian 509
Page, M. J.; Salvi, N. J.; Davis, S. W.
We examine the 3-10 keV EPIC spectra of Mrk 205 and 509 to investigate their Fe K features. The most significant feature in the spectra of both objects is an emission line at 6.4 keV. The spectra can be adequately modelled with a power law and a relatively narrow (σ < 0.2 keV) Fe Kα emission line. Better fits are obtained when an additional Gau…
A new model of solar EUV irradiance variability 2. Comparisons with empirical models and observations and implications for space weather
Mariska, J. T.; Warren, H. P.; Bishop, J. +1 more
Motivated by the need for reliable specification of the Sun's electromagnetic radiation in the extreme ultraviolet (EUV) spectrum, we have developed a new model of solar EUV irradiance variability at wavelengths from 50 to 1200 Å. Solar images are used to quantify changes in the sources of EUV irradiance during the solar cycle. Optically thin EUV …
Wavelike Properties of Solar Supergranulation Detected in Doppler Shift Data
Schou, J.
Recently, Gizon, Duvall, & Schou suggested that supergranulation has a wavelike component. In this Letter, I show that the same phenomenon can be observed using surface Doppler shift data, thereby confirming their observations, which were made using a helioseismic time-distance technique. In addition to confirming those results, I show that th…
The Trumpler 14 photodissociation region in the Carina Nebula
Poglitsch, A.; Schneider, N.; Cox, P. +4 more
We report the results of observations of the fine-structure emission lines [C II] 158 µm and [O I] 63 µm using FIFI on the Kuiper Airborne Observatory (KAO) and the Long Wavelength Spectrometer (LWS) on board ISO, towards the molecular cloud associated with the stellar cluster Trumpler 14 (Tr 14) in the Carina Nebula. These data are co…