69 citations · 69 across the 1 of their papers we have counts for
6 papers
V605 Aql: The Older Twin of Sakurai's Object
Geoffrey C. Clayton, F. Kerber, N. Pirzkal +3
New optical spectra have been obtained with VLT/FORS2 of the final helium shell flash (FF) star, V605 Aql, which peaked in brightness in 1919. New models suggest that this star is…
A Spectroscopic Analysis of Blue Stragglers, Horizontal Branch and Turn-Off Stars in Four Globular Clusters
Orsola De Marco, Michael M. Shara, D. Zurek +4
We present a spectroscopic analysis of HST/STIS and FOS low- and intermediate-resolution spectroscopy of 55 stars (turn-off stars, horizontal branch stars and blue stragglers) in f…
X-ray Imaging of Planetary Nebulae with Wolf-Rayet-type Central Stars: Detection of the Hot Bubble in NGC 40
Rodolfo Montez, Joel H. Kastner, Orsola De Marco +1
We present the results of Chandra X-ray Observatory (CXO) observations of the planetary nebulae (PNs) NGC 40 and Hen 2-99. Both PNs feature late-type Wolf-Rayet central stars that…
First Evidence of Circumstellar Disks around Blue Straggler Stars
Orsola De Marco, Thierry Lanz, John A. Ouellette +2
We present an analysis of optical HST/STIS and HST/FOS spectroscopy of 6 blue stragglers found in the globular clusters M3, NGC6752 and NGC6397. These stars are a subsample of a se…
Indications of a Large Fraction of Spectroscopic Binaries Among Nuclei of Planetary Nebulae
Orsola De Marco, Howard E. Bond, Dianne Harmer +1
Previous work indicates that about 10% of planetary-nebula nuclei (PNNi) are photometrically variable short-period binaries with periods of hours to a few days. These systems have…
Freshly ionized matter around the final Helium shell flash object V4334 Sgr (Sakurai's object)
F. Kerber, N. Pirzkal, Orsola De Marco +3
We report on the discovery of recently ionized hydrogen-deficient gas in the immediate circumstellar environment of the final helium shell flash star V4334 Sgr (Sakurai's object).…