Search Publications
Observations of the Ultraviolet-bright Star Y453 in the Globular Cluster M4 (NGC 6121)
Chayer, Pierre; Benjamin, Robert A.; Latour, Marilyn +2 more
We present a spectral analysis of the UV-bright star Y453 in M4. Model fits to the star’s optical spectrum yield {T}{eff} ∼ 56,000 K. Fits to the star’s FUV spectrum, obtained with the Cosmic Origins Spectrograph on board the Hubble Space Telescope, reveal it to be considerably hotter, with {T}{eff} ∼ 72,000 K. We adopt {T}
New Binaries in the ɛ Cha Association
Tokovinin, Andrei; Briceño, César
We present Adaptive Optics-aided speckle observations of 47 young stars in the ɛ Cha association made at the 4 m Southern Astrophysical Research Telescope in the I-band. We resolved 10 new binary pairs, 5 previously known binaries, and 2 triple systems, also previously known. In the separation range between 4 and 300 au, the 30 association members…
New Precision Orbits of Bright Double-lined Spectroscopic Binaries. X. HD 96511, HR 7578, and KZ Andromedae
Henry, Gregory W.; Fekel, Francis C.; Tomkin, Jocelyn
From an extensive number of newly acquired radial velocities we determine the orbital elements for three late-type dwarf systems, HD 96511, HR 7578, and KZ And. The orbital periods are 18.89737 ± 0.00002, 46.81610 ± 0.00006, and 3.0329113 ± 0.0000005 days, respectively, and all three systems are eccentric, although KZ And is just barely so. We hav…
Collisions of Terrestrial Worlds: The Occurrence of Extreme Mid-infrared Excesses around Low-mass Field Stars
Theissen, Christopher A.; West, Andrew A.
We present the results of an investigation into the occurrence and properties (stellar age and mass trends) of low-mass field stars exhibiting extreme mid-infrared (MIR) excesses ({L}{IR}/{L}* ≳ 0.01). Stars for the analysis were initially selected from the Motion Verified Red Stars (MoVeRS) catalog of photometric stars with …
Hubble Space Telescope Ultraviolet Light Curves Reveal Interesting Properties of CC Sculptoris and RZ Leonis
Szkody, Paula; Sion, Edward M.; Godon, Patrick +6 more
Time-tag ultraviolet data obtained on the Hubble Space Telescope in 2013 reveal interesting variability related to the white dwarf spin in the two cataclysmic variables RZ Leo and CC Scl. RZ Leo shows a period at 220 s and its harmonic at 110 s, thus identifying it as a likely Intermediate Polar (IP). The spin signal is not visible in a short sing…
Imaging Parity-violating Modes in the CMB
Contaldi, Carlo R.
Correlations of polarization components in the coordinate frame are a natural basis for searches of parity-violating modes in the cosmic microwave background. This fact can be exploited to build estimators of parity-violating modes that are local and robust with respect to partial-sky coverage or inhomogeneous weighting. As an example application …
FUSE Spectroscopy of the Accreting Hot Components in Symbiotic Variables
Sion, Edward M.; Godon, Patrick; Mikolajewska, Joanna +2 more
We have conducted a spectroscopic analysis of the far-ultraviolet archival spectra of four symbiotic variables, EG And, AE Ara, CQ Dra, and RW Hya. RW Hya and EG And have never had a recorded outburst, while CQ Dra and AE Ara have outburst histories. We analyze these systems while they are in quiescence in order to help reveal the physical propert…
Interpretation of a Variable Reflection Nebula Associated with HBC 340 and HBC 341 in NGC 1333
Hillenbrand, L. A.; Dahm, S. E.
We present multi-epoch, R-band imaging obtained from the Palomar Transient Factory of a small, fan-shaped reflection nebula in NGC 1333 that experiences prominent brightness fluctuations. Photometry of HBC 340 (K7e) and HBC 341 (M5e), a visual pair of late-type, young stellar objects lying near the apex of the nebula, demonstrates that while both …
Thermal Modeling of Comet-like Objects from AKARI Observation
Usui, Fumihiko; Ishiguro, Masateru; Bach, Yoonsoo P.
We investigated the physical properties of the comet-like objects 107P/(4015) Wilson-Harrington (4015WH) and P/2006 HR30 (Siding Spring; HR30) by applying a simple thermophysical model to the near-infrared spectroscopy and broadband observation data obtained by the AKARIsatellite of JAXA when they showed no detectable comet-like activity. We selec…
The Kepler Eclipsing Binary V2281 Cygni with Twin Stars
Koo, Jae-Rim; Hong, Kyeongsoo; Lee, Jae Woo
We present the physical properties of the eclipsing binary V2281 Cyg, which shows a light-time effect due to a supposed tertiary component from its eclipse timing variation according to the Kepler observations. The high-resolution spectra and BVR photometric data of the system were obtained at Bohyunsan Optical Astronomy Observatory and Mount Lemm…