Search Publications
Hubble Space Telescope Wide Field Planetary Camera 2 Observations of HH 1-2
Hester, J. Jeff; Stapelfeldt, Karl R.; Scowen, Paul A.
We present Hubble Space Telescope Wide Field Planetary Camera 2 images of the bipolar Herbig-Haro complex HH 1-2 in three emission lines (Hα, [S ii], and [O iii]) and one continuum band (F702W). In addition to showing the complex morphology of these objects, the WFPC2 data allow us to resolve the cooling and recombination regions behind radiative …
A New Analysis of RR Lyrae Kinematics in the Solar Neighborhood
Martin, John C.; Morrison, Heather L.
Full space velocities are computed for a sample of 130 nearby RR Lyrae variables using both ground-based and Hipparcos proper motions. In many cases proper motions for the same star from multiple sources have been averaged to produce approximately a factor of 2 improvement in the transverse space velocity errors. In most cases, this exceeds the ac…
The Ultracompact H II Region G5.97-1.17: an Evaporating Circumstellar Disk in M8
Henning, T.; Stecklum, B.; Hayward, T. L. +4 more
We present new high spatial resolution optical, infrared, and radio observations of G5.97-1.17, an ultracompact H ii region 2.7" distant from the O7 star Herschel 36 in the center of M8, the Lagoon Nebula. Infrared imaging was obtained using the adaptive optics system ADONIS on the ESO 3.6 m telescope and a thermal-IR camera on the Hale 5 m; optic…
Ionization Structure in the 30 Doradus Nebula as seen with Hubble Space Telescope Wide Field Planetary Camera 2
Watson, A. M.; Holtzman, J. A.; Stapelfeldt, K. R. +15 more
Using the Hubble Space Telescope (HST) and Wide Field Planetary Camera 2, we have imaged the central 20 pc of the giant H ii region 30 Doradus Nebula in three different emission lines. The images allow us to study the nebula with a physical resolution that is within a factor of 2 of that of typical ground-based observations of Galactic H ii region…
Integrated Ultraviolet Spectra and Line Indices of M31 Globular Clusters and the Cores of Elliptical Galaxies
Rieke, Marcia J.; Frogel, Jay A.; O'Connell, Robert W. +6 more
We present observations of the integrated light of four M31 globular clusters (MIV, MII, K280, and K58) and of the cores of six elliptical galaxies (NGC 3605, 3608, 5018, 5831, 6127, and 7619) made with the Faint Object Spectrograph on the Hubble Space Telescope. The spectra cover the range 2200-4800 Å at a resolution of 8 Å with signal-to-noise r…
The Southern Proper Motion Program. I. Magnitude Equation Correction
Kozhurina-Platais, Vera; Girard, Terrence M.; van Altena, William F. +2 more
As with virtually all photographic plate material, the astrograph plates from which the Southern Proper Motion (SPM) catalog is being compiled suffer from magnitude-dependent systematic shifts in the image positions, i.e., a magnitude equation. If left uncorrected, these would adversely affect both the primary goals of the SPM catalog, the absolut…
Hubble Space Telescope Imaging of the Mass-losing Supergiant VY Canis Majoris
Kastner, Joel H.; Weintraub, David A.
The highly luminous M supergiant VY CMa is a massive star that appears to be in its final death throes, losing mass at high rate en route to exploding as a supernova. Subarcsecond-resolution optical images of VY CMa, obtained with the Faint Object Camera (FOC) aboard the Hubble Space Telescope, vividly demonstrate that mass loss from VY CMa is hig…
Globular Cluster Photometry with the Hubble Space Telescope. VII. Color Gradients and Blue Stragglers in the Central Region of M30 from Wide Field Planetary Camera 2 Observations
Schneider, Donald P.; Yanny, Brian; Bahcall, John N. +2 more
We present F555W (V), F439W (B), and F336W (U) photometry of 9507 stars in the central 2' of the dense, post-core-collapse cluster M30 (NGC 7099) derived from Hubble Space Telescope Wide Field Planetary Camera 2 images. These data are used to study the mix of stellar populations in the central region of the cluster. Forty-eight blue straggler star…
ROSAT and HIPPARCOS Observations of Isolated Pre-Main-Sequence Stars near HD 98800
Cohen, David H.; Jensen, Eric L. N.; Neuhäuser, Ralph
We present new observations of the isolated young stars HD 98800 and CD -33 deg7795. Pointed ROSAT observations show that their X-ray properties, including X-ray luminosity and variability, are consistent with those of pre-main-sequence (PMS) stars. These observations do not reveal any additional PMS candidates in 40' fields centered on HD 98800 a…
The Age Range of Hyades Stars
Eggen, Olin J.
On the basis of canonical models, the age of Hyades supercluster stars, whether in the Hyades and Praesepe clusters or the noncluster field, ranges from (5-6) x 10^8 to 10^9 yr. The difference between the parallax derived from the supercluster motion and that obtained from Hipparcos observations has a dispersion only twice that of the mean dispers…