Analysis of the Hot Stellar Population of the Globular Cluster! Centauri (2007)
Jonathan H. Whitney, Robert T. Rood, Robert W. O'connell, Noella L. D'cruz, Ben Dorman, Wayne B. Landsman, ...
We analyze the far UV and Stromgren u photometric data of the globular cluster! Cen presented in an earlier paper (Whitney et al. 1994). The color-magnitude diagram of the cluster from these two...
THE ORIGIN OF EXTREME HORIZONTAL BRANCH STARS (2007)
Noella L. D'cruz, Ben Dorman, Robert T. Rood, Robert W. O'connell
Strong mass loss on the red giant branch (RGB) can result in the formation of extreme horizontal branch (EHB) stars. The EHB stars spend most of their He core & shell burning phase at high...
Age and Abundance Discrimination in Old Stellar Populations Using Mid-Ultraviolet Colors (2003)
Dorman, Ben, O'Connell, Robert W., Rood, Robert T.
The restframe mid-ultraviolet spectral region (2000-3200 A) is important in analyzing the stellar populations of the "red envelope" systems observed at high redshifts. Here, we explore the usefulness...
Blue Horizontal Branch Stars in Old, Metal-Rich Stellar Systems (2003)
Peterson, Ruth C., Carney, Bruce W., Dorman, Ben, Green, Elizabeth M., Landsman, Wayne, Liebert, James, ...
Twenty years ago, Burstein et al. (1984)suggested that strong CN and Hbeta absorption meant younger ages among globular clusters in the Andromeda galaxy (M31), unless blue stars above the...
Modeling Mid-Ultraviolet Spectra. I. Temperatures of Metal-Poor Stars (2000)
Peterson, Ruth C., Dorman, Ben, Rood, Robert T.
Determining the properties of old stellar systems using evolutionary population synthesis requires a library of reliable model stellar fluxes. Empirical libraries are limited to spectra of stars in...
HST Observations of New Horizontal Branch Structures in the Globular Cluster omega Centauri (1999)
D'Cruz, Noella L., O'Connell, Robert W., Rood, Robert T., Whitney, Jonathan H., Dorman, Ben, Landsman, Wayne B., ...
The globular cluster omega Centauri contains the largest known population of very hot horizontal branch (HB) stars. We have used the Hubble Space Telescope to obtain a far-UV/optical color-magnitude...
Blue Straggler Stars: The Spectacular Population in M80 (1999)
Ferraro, Francesco R., Paltrinieri, Barbara, Rood, Robert T., Dorman, Ben
Using HST-WFPC2 observations in two ultraviolet (UV) filters (F225W and F336W) of the central region of the high density Galactic Globular cluster (GGC) M80 we have identified 305 Blue Straggler...
Ultraviolet Imaging of the z=0.23 Cluster Abell 2246 (1998)
Cornett, Robert H., Dorman, Ben, Smith, Eric P., Fanelli, Michael A., Oegerle, William R., Bohlin, Ralph C., ...
We present deep ultraviolet observations of a field containing the cluster Abell 2246 (z=0.225) which provide far-ultraviolet (FUV) images of some of the faintest galaxies yet observed in that...
Multimodal Distributions along the Horizontal Branch (1997)
Ferraro, Francesco R., Paltrinieri, Barbara, Pecci, Flavio Fusi, Dorman, Ben, Rood, Robert T.
We report on HST/WFPC2 U,V and far-ultraviolet observations of two Galactic Globular Clusters (GGCs), NGC 6205 = M13 and NGC 6093 = M80. Both of these clusters have horizontal-branch (HB) tails that...
Ferraro, Francesco R., Paltrinieri, Barbara, Pecci, Flavio Fusi, Rood, Robert T., Dorman, Ben
The core of the galactic globular cluster M13 (NGC 6205) has been observed with WFPC2 on the Hubble Space Telescope through visual, blue and mid- and far-UV filters in a programme devoted to study...
Constraining the Abundances and Ages of Early-type Galaxies (1997)
Dorman, Ben, O'Connell, Robert W.
We consider the extent to which broadband mid-UV (2000 - 3000 Angstrom) colors can give superior constraints on the ages and abundances of old stellar populations than can their optical counterparts....
HST UV Observations of the Cores of M3 and M13 (1997)
Ferraro, Francesco R., Paltrinieri, Barbara, Pecci, Flavio Fusi, Cacciari, Carla, Dorman, Ben, Rood, Robert T.
We present preliminary results from HST/WFPC2 observations of the central regions of the of the Galactic globular clusters M13 and M3. The clusters are almost identical in most respects including...
Discovery of Extended Blue Horizontal Branches in Two Metal-Rich Globular Clusters (1997)
Rich, R. Michael, Sosin, Craig, Djorgovski, S. George, Piotto, Giampaolo, King, Ivan R., Renzini, Alvio, ...
We have used WFPC2 to construct B, V color-magnitude diagrams of four metal-rich globular clusters, NGC 104 (47 Tuc), NGC 5927, NGC 6388, and NGC 6441. All four clusters have well populated red...
Ultraviolet Imaging of the Globular Cluster 47 Tucanae (1997)
O'Connell, Robert W., Dorman, Ben, Shah, Ronak Y., Rood, Robert T., Landsman, Wayne B., Bohlin, Ralph C., ...
We have used the Ultraviolet Imaging Telescope to obtain deep far-UV (1620 Angstrom), 40' diameter images of the prototypical metal-rich globular cluster 47 Tucanae. We find a population of about 20...
UIT Detection of Hot Stars in the Globular Cluster NGC362 (1997)
Dorman, Ben, Shah, Ronak Y., O'Connell, Robert W., Landsman, Wayne B., Rood, Robert T., Bohlin, Ralph C., ...
We used the Ultraviolet Imaging Telescope during the March 1995 Astro-2 mission to obtain a deep far-UV image of the globular cluster NGC 362, which was formerly thought to have an almost entirely...
Peculiar Multimodality on the Horizontal Branch of the Globular Cluster NGC 2808 (1997)
Sosin, Craig, Dorman, Ben, Djorgovski, S. George, Piotto, Giampaolo, Rich, R. Michael, King, Ivan R., ...
We present distributions of colors of stars along the horizontal branch of the globular cluster NGC 2808, from Hubble Space Telescope WFPC2 imaging in B, V, and an ultraviolet filter (F218W). This...
The Far-Ultraviolet Radiation from Elliptical Galaxies (1997)
Since the discovery of the Ultraviolet Upturn Phenomenon (``UVX'') in early-type galaxies it has been clear that the stellar populations of such systems contain an unexpected hot component. Recent...
Ultraviolet Light from Old Stellar Populations (1996)
We consider the general theoretical problem of ultraviolet light from old stellar populations (t > 2 Gyr), and the interpretation of galaxy spectra at short wavelengths (lamda < 3200A) The sources...
The Potential of Asteroseismology for Hot, Subdwarf B Stars: A New Class of Pulsating Stars? (1996)
Charpinet, Stephane, Fontaine, Gilles, Brassard, Pierre, Dorman, Ben
We present key sample results of a systematic survey of the pulsation properties of models of hot B subdwarfs. We use equilibrium structures taken from detailed evolutionary sequences of solar...
The G Dwarf Problem Exists in Other Galaxies (1996)
Worthey, Guy, Dorman, Ben, Jones, Lewis
Stellar population models with abundance distributions determined from the analytic Simple model of chemical evolution fail to match observations of the nuclei of bulge-dominated galaxies in three...
Dixon, W. Van Dyke, Davidsen, Arthur F., Dorman, Ben, Ferguson, Harry
The globular cluster M79 was observed with the Hopkins Ultraviolet Telescope (HUT) during the Astro-1 space shuttle mission in 1990 December. The cluster's far-UV integrated spectrum shows strong...
Constraints on the Stellar Populations of Elliptical Galaxies from Ultraviolet Spectra (1996)
Dorman, Ben, O'Connell, Robert W.
We present preliminary results from spectral synthesis models of old stellar populations for the spectral range 912-4000 A with ~ 10A resolution, which can be used to investigate the UVX phenomenon...
A database for galaxy evolution modeling (1996)
Leitherer, Claus, Alloin, Danielle, Alvensleben, Uta Fritze-V, Gallagher, John, Huchra, John, Matteucci, Francesca, ...
This paper represents a collective effort to provide an extensive electronic database useful for the interpretation of galaxy properties.
A database for galaxy evolution modeling (1996)
Leitherer, Claus, Alloin, Danielle, Alvensleben, Uta Fritze-V, Gallagher, John, Huchra, John, Matteucci, Francesca, ...
This paper represents a collective effort to provide an extensive electronic database useful for the interpretation of galaxy properties.
A database for galaxy evolution modeling (1996)
Leitherer, Claus, Alloin, Danielle, Alvensleben, Uta Fritze-V, Gallagher, John, Huchra, John, Matteucci, Francesca, ...
This paper represents a collective effort to provide an extensive electronic database useful for the interpretation of galaxy properties.
A database for galaxy evolution modeling (1996)
Leitherer, Claus, Alloin, Danielle, Alvensleben, Uta Fritze-V, Gallagher, John, Huchra, John, Matteucci, Francesca, ...
This paper represents a collective effort to provide an extensive electronic database useful for the interpretation of galaxy properties.
Horizontal Branch Stellar Evolution (1995)
I review aspects of the evolution of horizontal branch (HB) stars. I start by discussing current topics in the study of HB stellar evolution, including a brief review of the main determinants of the...
The Origin of Extreme Horizontal Branch Stars (1995)
D'Cruz, Noella Lambert, Dorman, Ben, Rood, Robert T., O'Connell, Robert W.
Strong mass loss on the red giant branch (RGB) can result in the formation of extreme horizontal branch (EHB) stars. The EHB stars spend most of their He core and shell burning phase at high...
Derived Parameters for NGC 6791 from High-Metallicity Isochrones (1995)
Tripicco, Michael J., Bell, Roger A., Dorman, Ben, Hufnagel, Beth
We have computed 8, 10, and 12 Gyr isochrones and physically consistent models of zero-age red horizontal branch stars for stellar masses between 0.55 and 1.3~\msun, all at [Fe/H] $=+0.15$....
Dorman, Ben, O'Connell, Robert W., Rood, Robert T.
We present an analysis of the far-ultraviolet upturn phenomenon (UVX) observed in elliptical galaxies and spiral galaxy bulges. Our premise is that the UV radiation from these systems emanates...
Are Analogues of Hot Subdwarf Stars Responsible for the UVX Phenomenon in Galaxy Nuclei? (1994)
Dorman, Ben, O'Connell, R. W., Rood, R. T.
We present the case that populations of sdB/sdOB/sdO-type stars may be a common constituent of galactic stellar populations, responsible for the UV upturn (`UVX') observed in the spectra of spiral...
Mass Loss In M67 Giants: Evidence From Isochrone Fitting (1993)
Tripicco, Michael J., Dorman, Ben, Bell, Roger A.
We present a study of the stellar content of the open cluster M67. We have computed new evolutionary sequences of stellar models with solar abundance that cover all phases of evolution from the...