Search Publications
Hubble Space Telescope CALSPEC Flux Standards: Sirius (and Vega)
Bohlin, R. C.
The Space Telescope Imaging Spectrograph (STIS) has measured the flux for Sirius from 0.17 to 1.01 µm on the Hubble Space Telescope (HST) White Dwarf scale. Because of the cool debris disk around Vega, Sirius is commonly recommended as the primary IR flux standard. The measured STIS flux agrees well with predictions of a special Kurucz model…
A CO Survey in Planet-forming Disks: Characterizing the Gas Content in the Epoch of Planet Formation
Ménard, F.; Casassus, S.; Eiroa, C. +13 more
We carried out a 12CO(3-2) survey of 52 southern stars with a wide range of IR excesses (L IR/L *) using the single-dish telescopes APEX and ASTE. The main aims were (1) to characterize the evolution of molecular gas in circumstellar disks using L IR/L * values as a proxy of disk dust evolutio…
The Solar Neighborhood. XXXI. Discovery of an Unusual Red+White Dwarf Binary at ~25 pc via Astrometry and UV Imaging
Gies, Douglas R.; Henry, Todd J.; Winters, Jennifer G. +4 more
We report the discovery of a nearby M5.0V dwarf at 24.6 pc, SCR 1848-6855, that is orbited by an unusual companion causing an astrometric perturbation of more than 200 mas. This is by far the largest perturbation found to date among more than 700 targets observed during our long-term astrometry/photometry program at the CTIO 0.9 m telescope. We pr…
Dusty Disks around Central Stars of Planetary Nebulae
Rauch, Thomas; De Marco, Orsola; Chu, You-Hua +4 more
Only a few percent of cool, old white dwarfs (WDs) have infrared excesses interpreted as originating in small hot disks due to the infall and destruction of single asteroids that come within the star's Roche limit. Infrared excesses at 24 µm were also found to derive from the immediate vicinity of younger, hot WDs, most of which are still ce…
Interesting Features in the Combined GALEX and Sloan Color Diagrams of Solar-like Galactic Populations
Smith, Myron A.; Bianchi, Luciana; Shiao, Bernard
We report on intriguing photometric properties of Galactic stars observed in the Galaxy Evolution Explorer (GALEX) satellite's far-UV (FUV) and near-UV (NUV) bandpasses, as well as from the ground-based Sloan Digital Sky Survey (SDSS) and the Kepler Input Catalog. The first property is that the (FUV - NUV) color distribution of stars in the Kepler…
The Three-body System δ Circini
Mayer, Pavel; Harmanec, Petr; Sana, Hugues +1 more
Delta Cir is known as an O7.5 III eclipsing and spectroscopic binary with an eccentric orbit. Penny et al. discovered the presence of a third component in the IUE spectra. The eclipsing binary and the third body revolve around a common center of gravity with a period of 1644 days in an eccentric orbit with a semimajor axis of 10 AU. We demonstrate…