Search Publications
Empirically Constrained Color-Temperature Relations. I. BV(RI)C
VandenBerg, Don A.; Clem, James L.
This investigation presents a set of transformations to Johnson B-V, Cousins V-R, and Cousins V-I, as well as bolometric corrections to V, for [Fe/H]=-3, -2, -1, -0.5, 0.0, and +0.3 and, in each case, values of logg from -0.5 to 5.0 for 3000 K<=Teff<=5500 K and from 2.0 to 5.0 for 6000 K<=Teff<=40,000 K. These tra…
Hubble Space Telescope Observations of Binary Very Low Mass Stars and Brown Dwarfs
Kirkpatrick, J. Davy; Burgasser, Adam J.; Gizis, John E. +4 more
We present analysis of Hubble Space Telescope (HST) images of 82 nearby field late M and L dwarfs. We resolve 13 of these systems into double M/L dwarf systems and identify an additional possible binary. Combined with previous observations of 20 L dwarfs, we derive an observed binary fraction for ultracool dwarfs of 17+4-3%, …
Spectral Irradiance Calibration in the Infrared. XIII. ``Supertemplates'' and On-Orbit Calibrators for the SIRTF Infrared Array Camera
Megeath, S. T.; Stauffer, John; Cohen, Martin +2 more
We describe the technique that will be used to develop a set of on-orbit calibrators for the Infrared Array Camera (IRAC) and demonstrate the validity of the method for stars with spectral types either K0-M0 III or A0-A5 V. For application to SIRTF, the approach is intended to operate with all available optical, near-infrared (NIR), and mid-infrar…
The Tycho-2 Spectral Type Catalog
Egan, Michael P.; Kraemer, Kathleen E.; Price, Stephan D. +1 more
The Tycho-2 Catalogue contains positions, proper motions, and BT and VT magnitudes for approximately 2.5 million stars. We have obtained spectral types for 351,864 of the Tycho-2 stars by cross-referencing Tycho-2 to several catalogs containing spectral types, using the VizieR astronomical database. The positional matching re…
Stellar Kinematic Groups. II. A Reexamination of the Membership, Activity, and Age of the Ursa Major Group
Adelman, Saul J.; Soderblom, David R.; King, Jeremy R. +2 more
Utilizing Hipparcos parallaxes, original radial velocities and recent literature values, new Ca II H and K emission measurements, literature-based abundance estimates, and updated photometry (including recent resolved measurements of close doubles), we revisit the Ursa Major moving group membership status of some 220 stars to produce a final clean…
The Globular Cluster System of NGC 1399. I. A Wide-Field Photometric Study
Geisler, D.; Dirsch, B.; Richtler, T. +3 more
We present a photometric investigation of the globular cluster population of NGC 1399, the central galaxy in the Fornax cluster, in Washington C and Kron R filters within a field of 36'×36', corresponding to about 200×200 kpc at the Fornax distance. This is the largest area around this galaxy ever studied with CCD photometry. The cluster system of…
Optical and Infrared Photometry of the Nearby Type Ia Supernova 2001el
Candia, Pablo; Krisciunas, Kevin; Phillips, Mark M. +8 more
We present well-sampled optical (UBVRI) and infrared (JHK) light curves of the nearby (~18.0 Mpc) Type Ia supernova SN 2001el, from 11 days before to 142 days after the time of B-band maximum. The data represent one of the best sets of optical and infrared photometry ever obtained for a Type Ia supernova (SN). Based on synthetic photometry using o…
Hubble Space Telescope ACS Coronagraphic Imaging of the Circumstellar Disk around HD 141569A
Ford, H. C.; Infante, L.; Zheng, W. +31 more
Multicolor coronagraphic images of the circumstellar disk around HD 141569A have been obtained with the Hubble Space Telescope Advanced Camera for Surveys. The B, V, and I images show that the disk's previously described multiple-ring structure is actually a continuous distribution of dust with a tightly wound spiral structure. Extending from the …
Spectroscopic Binaries, Velocity Jitter, and Rotation in Field Metal-poor Red Giant and Red Horizontal-Branch Stars
Latham, David W.; Stefanik, Robert P.; Morse, Jon A. +2 more
We summarize 2007 radial velocity measurements of 91 metal-poor field red giants. Excluding binary systems with orbital solutions, our coverage averages 13.7 yr per star, with a maximum of 18.0 yr. We report four significant findings. (1) Sixteen stars are found to be spectroscopic binaries, and we present orbital solutions for 14 of them. The spe…
Hubble Space Telescope Imaging of Brightest Cluster Galaxies
O'Dea, Christopher P.; van der Marel, Roeland P.; Lauer, Tod R. +3 more
We used the Hubble Space Telescope Wide Field Planetary Camera 2 to obtain I-band images of the centers of 81 brightest cluster galaxies (BCGs), drawn from a volume-limited sample of nearby BCGs. The images show a rich variety of morphological features, including multiple or double nuclei, dust, stellar disks, point-source nuclei, and central surf…