Search Publications
Detection of Diffuse X-Ray Emission from Planetary Nebulae with Nebular O VI
Steffen, M.; Gruendl, R. A.; Chu, Y. -H. +4 more
The presence of O VI ions can be indicative of plasma temperatures of a few ×105 K that are expected in heat conduction layers between the hot shocked stellar wind gas at several 106 K and the cooler (104 K) nebular gas of planetary nebulae (PNe). We have used FUSE observations of PNe to search for nebular O VI emi…
Further Evidence of the Planetary Nature of HD 95086 b from Gemini/NICI H-band Data
Boccaletti, A.; Lagrange, A. -M.; Bonnefoy, M. +8 more
We present our analysis of the Gemini/NICI H-band data of HD 95086, following the discovery of the planet HD 95086 b in L'. The H-band data reach a contrast of 12.7 mag relative to the host star at 5σ levels in the location of HD 95086 b, and no point source is found. Our non-detection and H - L' color limit rules out the possibility that the obje…
Copious Amounts of Hot and Cold Dust Orbiting the Main Sequence A-type Stars HD 131488 and HD 121191
Zuckerman, B.; Murphy, Simon J.; Song, Inseok +3 more
We report two new dramatically dusty main sequence stars: HD 131488 (A1 V) and HD 121191 (A8 V). HD 131488 is found to have substantial amounts of dust in its terrestrial planet zone (L IR/L bol ≈ 4 × 10-3), cooler dust farther out in its planetary system, and an unusual mid-infrared spectral feature. HD 121191 sho…
Characterizing the Dust Coma of Comet C/2012 S1 (ISON) at 4.15 AU from the Sun
Kolokolova, Ludmilla; Weaver, Harold A.; A'Hearn, Michael F. +7 more
We report results from broadband visible images of comet C/2012 S1 (ISON) obtained with the Hubble Space Telescope Wide Field Camera 3 on 2013 April 10. C/ISON's coma brightness follows a 1/ρ (where ρ is the projected distance from the nucleus) profile out to 5000 km, consistent with a constant speed dust outflow model. The turnaround distance in …
Timing and Interstellar Scattering of 35 Distant Pulsars Discovered in the PALFA Survey
Popa, L.; Camilo, F.; Ransom, S. M. +34 more
We have made extensive observations of 35 distant slow (non-recycled) pulsars discovered in the ongoing Arecibo PALFA pulsar survey. Timing observations of these pulsars over several years at Arecibo Observatory and Jodrell Bank Observatory have yielded high-precision positions and measurements of rotation properties. Despite being a relatively di…
The Location of Non-thermal Velocity in the Early Phases of Large Flares—Revealing Pre-eruption Flux Ropes
Culhane, J. L.; Harra, Louise K.; Hara, Hirohisa +3 more
Non-thermal velocity measurements of the solar atmosphere, particularly from UV and X-ray emission lines have demonstrated over the decades that this parameter is important in understanding the triggering of solar flares. Enhancements have often been observed before intensity enhancements are seen. However, until the launch of Hinode, it has been …
A CHARA Array Survey of Circumstellar Disks around Nearby Be-type Stars
Gies, D. R.; Goldfinger, P. J.; McAlister, H. A. +11 more
We report on a high angular resolution survey of circumstellar disks around 24 northern sky Be stars. The K-band continuum survey was made using the CHARA Array long baseline interferometer (baselines of 30-331 m). The interferometric visibilities were corrected for the flux contribution of stellar companions in those cases where the Be star is a …
Complex Diffuse Radio Emission in the Merging Planck ESZ Cluster A3411
van Weeren, R. J.; Forman, W. R.; Murray, S. S. +7 more
We present Very Large Array (VLA) radio and Chandra X-ray observations of the merging galaxy cluster A3411. For the cluster, we find an overall temperature of 6.4^{+0.6}_{-1.0} keV and an X-ray luminosity of 2.8 ± 0.1 × 1044 erg s-1 between 0.5 and 2.0 keV. The Chandra observation reveals the cluster to be undergoing a merger…
Hot Water in the Inner 100 AU of the Class 0 Protostar NGC 1333 IRAS2A
Bergin, Edwin A.; van Dishoeck, Ewine F.; Visser, Ruud +2 more
Evaporation of water ice above 100 K in the inner few 100 AU of low-mass embedded protostars (the so-called hot core) should produce quiescent water vapor abundances of ~10-4 relative to H2. Observational evidence so far points at abundances of only a few 10-6. However, these values are based on spherical models, w…
B- and A-type Stars in the Taurus-Auriga Star-forming Region
Padgett, Deborah; Rebull, Luisa; Mooley, Kunal +2 more
We describe the results of a search for early-type stars associated with the Taurus-Auriga molecular cloud complex, a diffuse nearby star-forming region noted as lacking young stars of intermediate and high mass. We investigate several sets of possible O, B, and early A spectral class members. The first is a group of stars for which mid-infrared i…