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HST Imagery of the Non-Expanding, Clumped "Shell" of the Recurrent Nova T Pyxidis
Williams, Robert E.; Zurek, David R.; Moffat, Anthony F. J. +3 more
The "shell" of the recurrent nova T Pyxidis has been resolved with HST imagery into more than two thousand individual knots. Hydrogen and [N II] emission have very similar spatial distributions. Four epochs of observation allow us to place an upper limit of 40 km/s on the systematic expansion velocity of the knots. This is in contrast to our 1985 …
Molecular Hydrogen in the Direction of ζ Orionis A
Jenkins, Edward B.; Peimbert, Antonio
A spectrum of ζ Ori A over the wavelength interval 950-1150 Å recorded by the Interstellar Medium Absorption Profile Spectrograph (IMAPS) on the ORFEUS-SPAS I mission shows Lyman and Werner band absorption features from molecular hydrogen in rotational levels J = 0, 1, 2, 3, and 5. Most of the molecules are found in two distinct velocity component…
First View of the Solar Core from GOLF Acoustic Modes
Baudin, F.; Christensen-Dalsgaard, J.; Eff-Darwich, A. +16 more
After 8 months of nearly continuous measurements the GOLF instrument, aboard SOHO, has detected acoustic mode frequencies of more than 100 modes, extending from 1.4 mHz to 4.9 mHz. In this paper, we compare these results with the best available predictions coming from solar models. To verify the quality of the data, we examine the asymptotic seism…
Solar-type stars with planetary companions: 51 Pegasi and 47 Ursae Majoris.
Fuhrmann, K.; Pfeiffer, M. J.; Bernkopf, J.
Accurate stellar parameters are presented for the solar-type stars 51 Peg and 47 UMa. The announcement of the detection of jovian planets around these objects has recently caused much attention to extrasolar planet research. From the analysis of high resolution spectrograms we obtain for 51 Peg: T_eff_=5793+/-70K, log(g)=4.33+/-0.1, [Fe/H]=+0.20+/…
The Structure of the Super-Star Clusters in NGC 1569 from Hubble Space Telescope WFPC2 Images
Leitherer, Claus; Clampin, Mark; Nota, Antonella +3 more
We present high-resolution observations of the super-star clusters in the nearby irregular galaxy NGC 1569, obtained with the WFPC2 on board the Hubble Space Telescope. Our analysis shows that the brightest of these clusters, NGC 1569A, results from the superposition of two clusters with an angular separation of ~0.2". Recent ground-based spectros…
Evolution of Cluster Ellipticals at 0.2 < z < 1.2 from Hubble Space Telescope Imaging,
Barrientos, L. Felipe; López-Cruz, Omar; Schade, David
Two-dimensional surface photometry derived from Hubble Space Telescope imaging is presented for a sample of 225 early-type galaxies (assumed to be cluster members) in the fields of nine clusters at redshifts 0.17 < z < 1.21. The 94 luminous ellipticals (MAB(B) < -20 selected by morphology alone with no reference to color) form …
The Apparent Morphology of Peculiar Galaxies at Intermediate to High Redshifts
Vacca, W. D.; Hibbard, J. E.
To understand the range of morphologies observed in the galaxy population at high redshift, it is instructive to evaluate the appearance of local peculiar galaxies when placed at cosmological distances. To this end, we use rest-frame ultraviolet (UV), B- and V-band images of five nearby (ζ<0.02) interacting and/or starbursting galaxies to simul…
Kinematics of the Interstellar Medium in NGC 1705: Implications for Distant Star-Forming Galaxies
Heckman, Timothy M.; Leitherer, Claus
We report the results of space-ultraviolet (UV) spectroscopy of the super star cluster `1' in the nearby dwarf starburst galaxy NGC 1705, using the Goddard High Resolution Spectrograph on the Hubble Space Telescope. The exceptionally high UV flux and surface brightness of NGC 1705-1 makes it ideal for studying how UV spectral diagnostics can be us…
The Variability and Spectrum of NGC 5548 in the Extreme Ultraviolet
Malkan, M. A.; Clavel, J.; Kriss, G. A. +8 more
We have measured the light curve and spectrum of NGC 5548 obtained with the Extreme Ultraviolet Explorer (EUVE) during a period when the galaxy was also intensively monitored with the Hubble Space Telescope, the International Ultraviolet Explorer, and ground-based telescopes. NGC 5548 was observed with EUVE for a total of about 20 days spread over…
Low-Mass Binaries in the Hyades: A Scarcity of Brown Dwarfs
Gizis, John E.; Reid, I. Neill
We have obtained HST Planetary Carnera observations of a total of 53 low-mass (M<0.3Msun) members of the Hyades cluster. Nine of these stars are resolved as binaries, with separations between 0.1 and 3.1 arcseconds, while a further three are probably equal-mass systems at smaller separations. Allowing for observational selection effe…