Search Publications
Interstellar Extinction Toward the CAS OB6 Association: Where is the Dust?
Clayton, Geoffrey C.; Hanson, Margaret Murray
We have completed a multiband (ultraviolet, optical, and near-infrared) study of the interstellar extinction properties of nine massive stars in IC 1805 and IC 1848, which are both part of Cas OB6 in the Perseus spiral arm. Our analysis includes determination of absolute extinction over the wavelength range from 3 micrometers to 1250 A. We have at…
Faint Object Camera Observations of the Shape and Expansion of SN 1987A
Panagia, N.; Jakobsen, P.; Macchetto, F.
New visible and near-UV imagery of SN 1987A obtained 1754 days after outburst with the Faint Object Camera on-board the Hubble Space Telescope is presented. A comparison between these data and previous FOC observations obtained 1278 days after outburst reveal that the supernova dimmed by a factor 0.35 +/- 0.04 between the two observations, corresp…
ULYSSES precise localizations of gamma-ray bursts.
Cline, T.; Hurley, K.; Kouveliotou, C. +10 more
The Ulysses mission is presently about 5 AU from Earth, in the vicinity of Jupiter. It carries a gamma-ray burst detector sensitive to ≈ 15 - 150 keV X-rays, with time resolution down to 8 ms. for the purpose of high accuracy burst localization by the time-of-arrival method. This spacecraft, which is farther from Earth than any previous mission wi…
First Ultraviolet Spectropolarimetry of Radio-selected BL Lacertae Objects
Smith, Paul S.; Allen, Richard G.; Angel, J. R. P.
We present ultraviolet spectropolarimetry of the BL Lac objects OJ 287 and 0754+100 (OI 090.4) acquired with the Faint Object Spectrograph of the Hubble Space Telescope. These are the first such observations of radio-selected BL Lac objects and the polarimetry spans the wavelength range 1580-3300 A in the observer's frame. Neither object exhibited…
A Spectroscopic Search for Colliding Stellar Winds in O-Type Close Binary Systems. IV. IOTA Orionis
Wiggs, Michael S.; Gies, Douglas R.; Bagnuolo, William G., Jr.
We present H-alpha and He I 6678 A line profiles for the eccentric orbit binary Iota Ori. We have applied a tomography algorithm which uses the established orbital velocity curves and intensity ratio to reconstruct the spectral line profiles for each star. The He I profiles appear as pure photospheric lines, and H-alpha shows variable emission in …
Doppler tomography of O-type binaries: The physical properties of seven systems
Gies, D. R.; Penny, L. R.; Bagnuolo, W. G.
We have analyzed UV photospheric lines of seven O-type binaries, by means of crosscorrelation and Doppler tomographic methods, with the goal of estimating the physical properties of the individual stars. These systems are HD 1337 (AO Cas), HD 47129 (Plaskett's star), HD 57060 (29 UW CMa), HD 37043 (Iota Ori), HD 215835 (DH Cep), HD 152218, and HD …
Solar energetic particles in the intermediate region of the heliosphere
Kunow, H.; Wibberenz, G.; Heber, B. +2 more
Energetic particle increases in the energy range 4 to 130 MeV observed by the Kiel Electron Telescope (KET) during the in-ecliptic part of the ULYSSES mission between 1 and 5.4 AU differ distinctly from their appearance in the inner heliosphere inside 1 AU. Prompt events are rare, and for most of the events velocity dispersion is lacking. The obse…
The Orbit and Companion of the Cepheid S SGE: A Probable Triple System
Evans, Nancy R.; Welch, Douglas L.; Slovak, Mark H. +2 more
New radial velocities for the classical Cepheid S Sge have been obtained and combined with previous observations to derive a new orbit. The revised orbital elements are: gamma, -10.3 +/- 0.4 km/s; K, 15.5 +/- 0.2 km/s; e, 0.23 +/- 0.02; omega, 203.1 +/- 4.2 deg; T0, 39902.3 +/- 6.6 JD; P, 675.79 +/- 0.18 days; f(m), 0.239 +/- 0.010 solar masses; a…
Langmuir wave decay and collapse in the Jovian foreshock
Kellogg, Paul J.; Thiessen, Jerold P.
Langmuir waves are known to be created upstream of planetary bow shocks by the two-stream instability driven by sunward-streaming particles. In this paper we examine Langmuir waves detected by Ulysses' Unified Radio and Plasma wave experiment (URAP) upstream of Jupiter. Wave envelopes qualitatively consistent with collapsed Langmuir waves are comm…
Possible discovery of threeγ-ray pulsars
Yu, K. N.; Young, E. C. M.; Lu, Tan +1 more
The possible discovery of threeγ-ray pulsars 0656 + 14, 0950 + 08, and 1822 - 09 based on COS-B data analysis is reported. Their light curves, the other related features, and the methods leading to these results are also given. Among these three pulsars, PSR 0656 + 14 is the most significant one for being aγ-ray pulsar.