Search Publications
Observational Estimates for the Mass-Loss Rates of α Centauri and Proxima Centauri Using Hubble Space Telescope Lyα Spectra
Zank, Gary P.; Wood, Brian E.; Linsky, Jeffrey L. +1 more
We study H I Lyα absorption observed by the Hubble Space Telescope toward the nearby binary system α Centauri (G2 V + K0 V) and its distant companion star Proxima Centauri (M5.5 Ve). Absorption from heliospheric H I heated by the solar wind/interstellar medium interaction is observed toward both α Cen and Proxima Cen. Absorption from analogous ``a…
Methylpolyynes and Small Hydrocarbons in CRL 618
Waters, L. B. F. M.; Cernicharo, José; Tielens, A. G. G. M. +5 more
We report on the detection with the Infrared Space Observatory of strong infrared absorption from NH3 and C2H4 in CRL 618. The observed NH3 and C2H4 bands arise from a region with kinetic temperatures ~=200 K, i.e., the dense gas in the photodissociation region associated to the den…
Luminous Compact Galaxies at Intermediate Redshifts: Progenitors of Bulges of Massive Spirals?
Infante, Leopoldo; Hammer, François; Thuan, Trinh X. +2 more
VLT spectra of 14 luminous compact galaxies (LCGs) reveal strong metallic absorption-line systems as well as narrow and intense emission lines. Their gas extinction is found to be large (AV~1.5 mag), leading to an upward revision of their star formation rate (SFR) to an average value of ~40 Msolar yr-1. Large extin…
High-Resolution Near-Infrared Images and Models of the Circumstellar Disk in HH 30
Schneider, Glenn; Rieke, Marcia; Wood, Kenneth +6 more
We present Hubble Space Telescope near-infrared camera and multiobject spectrometer observations of the reflection nebulosity associated with the T Tauri star HH 30. The images show the scattered-light pattern characteristic of a highly inclined, optically thick disk with a prominent dust lane whose width decreases with increasing wavelength. The …
Hubble Space Telescope Spectroscopy of V471 Tauri: Oversized K Star, Paradoxical White Dwarf
Bond, Howard E.; Sion, Edward M.; O'Brien, M. Sean
We have used the Goddard High Resolution Spectrograph on board the Hubble Space Telescope to obtain Lyα spectra of the hot white dwarf (WD) component of the short-period eclipsing DA+dK2 precataclysmic binary V471 Tauri, a member of the Hyades star cluster. Radial velocities of the WD were determined from eight post-COSTAR spectra obtained near th…
Observational Constraints on Coronal Heating Models Using Coronal Diagnostics Spectrometer and Soft X-Ray Telescope Data
Schmelz, J. T.; Scopes, R. T.; Cirtain, J. W. +2 more
We have constructed a multithermal differential emission measure distribution for several pixels along a relatively isolated coronal loop on the southwest limb of the solar disk using spectral line data from the Solar and Heliospheric Observatory coronal diagnostics spectrometer (CDS) and broadband data from the Yohkoh soft X-ray telescope. The te…
Source Regions of Coronal Mass Ejections
Dere, K. P.; Subramanian, Prasad
Observations of the solar corona with the Large Angle and Spectrometric Coronagraph Experiment (LASCO) and EUV Imaging Telescope (EIT) instruments on the Solar and Heliospheric Observatory (SOHO) provide an unprecedented opportunity to study coronal mass ejections (CMEs) from their initiation through their evolution out to 30 Rsolar. Th…
SOHO Observations of a Coronal Mass Ejection
Vourlidas, Angelos; Wu, R.; Raymond, John C. +5 more
We describe a coronal mass ejection (CME) observed on 1999 April 23 by the Ultraviolet Coronagraph Spectrometer (UVCS), the Extreme-Ultraviolet Imaging Telescope (EIT), and the Large-Angle and Spectrometric Coronagraphs (LASCO) aboard the Solar and Heliospheric Observatory (SOHO). In addition to the O VI and C III lines typical of UVCS spectra of …
Detection of Cosmic Shear with the Hubble Space Telescope Survey Strip
Refregier, Alexandre; Rhodes, Jason; Groth, Edward J.
Weak lensing by large-scale structure provides a unique method to directly measure matter fluctuations in the universe and has recently been detected from the ground. Here we report the first detection of this ``cosmic shear'' based on space-based images. The detection was derived from the Hubble Space Telescope (HST) Survey Strip (or ``Groth Stri…
The Proper Motion, Parallax, and Origin of the Isolated Neutron Star RX J185635-3754
Walter, Frederick M.
The isolated neutron star RX J185635-3754 is the closest known neutron star to the Sun. Based on Hubble Space Telescope Wide Field Planetary Camera 2 observations over a 3 yr baseline, I report its proper motion (332+/-1 mas yr-1 at a position angle of 100.3d+/-0.1d) and parallax (16.5+/-2.3 mas, 61 pc). This proper motion brings the ne…