Search Publications
A H I Imaging Survey of Asymptotic Giant Branch Stars
Le Bertre, T.; Matthews, L. D.; Johnson, M. C. +1 more
We present an imaging study of a sample of eight asymptotic giant branch stars in the H I 21 cm line. Using observations from the Very Large Array, we have unambiguously detected H I emission associated with the extended circumstellar envelopes of six of the targets. The detected H I masses range from M H I ≈ 0.015-0.055 M solar
Herschel Observations of Cataclysmic Variables
Harrison, Thomas E.; Campbell, Ryan K.; Tappert, Claus +2 more
We have used the PACS instrument on the Herschel Space Observatory to observe eight cataclysmic variables at 70 and 160 µm. Of these eight objects, only AM Her was detected. We have combined the Herschel results with ground-based, Spitzer, and WISE observations to construct spectral energy distributions for all of the targets. For the two dw…
Meter-sized Moonlet Population in Saturn's C Ring and Cassini Division
Colwell, Joshua E.; Esposito, Larry W.; Lewis, Mark C. +1 more
Stellar occultations observed by the Cassini Ultraviolet Imaging Spectrograph reveal the presence of transparent holes a few meters to a few tens of meters in radial extent in otherwise optically thick regions of the C ring and the Cassini Division. We attribute the holes to gravitational disturbances generated by a population of ~10 m boulders in…
Hipparcos Photocentric Orbits of 72 Single-lined Spectroscopic Binaries
Ren, Shulin; Fu, Yanning
By fitting the Hipparcos Intermediate Astrometric Data (HIAD), photocentric orbits can be obtained for the single-lined spectroscopic binaries (SB1s). In previous work, a simplifying approximation used in the fitting process was that the photocenter coincides with the primary, but simple arguments based on a mass-luminosity relation show that this…
HST/WFC3 Observations of Low-mass Globular Clusters AM 4 and Palomar 13: Physical Properties and Implications for Mass Loss
Dolphin, Andrew E.; Smith, Graeme H.; Grillmair, Carl J. +4 more
We investigate the loss of low-mass stars in two of the faintest globular clusters known, AM 4 and Palomar 13 (Pal 13), using HST/WFC3 F606W and F814W photometry. To determine the physical properties of each cluster—age, mass, metallicity, extinction, and present day mass function (MF)—we use the maximum likelihood color-magnitude diagram (CMD) fi…
The Vast Population of Wolf-Rayet and Red Supergiant Stars in M101. I. Motivation and First Results
Drissen, Laurent; Moffat, Anthony F. J.; Shara, Michael M. +3 more
Assembling a catalog of at least 10,000 Wolf-Rayet (W-R) stars is an essential step in proving (or disproving) that these stars are the progenitors of Type Ib and Type Ic supernovae. To this end, we have used the Hubble Space Telescope (HST) to carry out a deep, He II optical narrowband imaging survey of the ScI spiral galaxy M101. Almost the enti…
A Detailed Spatiokinematic Model of the Conical Outflow of the Multipolar Planetary Nebula NGC 7026
López, J. A.; Steffen, W.; Richer, M. G. +1 more
We present extensive, long-slit, high-resolution coverage of the complex planetary nebula (PN) NGC 7026. We acquired 10 spectra using the Manchester Echelle Spectrometer at San Pedro Martir Observatory in Baja California, Mexico, and each shows exquisite detail, revealing the intricate structure of this object. Incorporating these spectra into the…
HH 222: A Giant Herbig-Haro Flow from the Quadruple System V380 Ori
Kraus, Stefan; Bally, John; Geballe, T. R. +5 more
HH 222 is a giant shocked region in the L1641 cloud, and is popularly known as the Orion Streamers or "the waterfall" on account of its unusual structure. At the center of these streamers are two infrared sources coincident with a nonthermal radio jet aligned along the principal streamer. The unique morphology of HH 222 has long been associated wi…
Late-time Dust Emission from the Type IIn Supernova 1995N
Van Dyk, Schuyler D.
Type IIn supernovae (SNe IIn) have been found to be associated with significant amounts of dust. These core-collapse events are generally expected to be the final stage in the evolution of highly massive stars, either while in an extreme red supergiant phase or during a luminous blue variable phase. Both evolutionary scenarios involve substantial …
Very Low Mass Stellar and Substellar Companions to Solar-like Stars from MARVELS. IV. A Candidate Brown Dwarf or Low-mass Stellar Companion to HIP 67526
Bizyaev, Dmitry; Brewington, Howard; Ebelke, Garrett +50 more
We report the discovery of a candidate brown dwarf (BD) or a very low mass stellar companion (MARVELS-5b) to the star HIP 67526 from the Multi-object Apache point observatory Radial Velocity Exoplanet Large-area Survey (MARVELS). The radial velocity curve for this object contains 31 epochs spread over 2.5 yr. Our Keplerian fit, using a Markov Chai…