Search Publications
CCD Measurements of Double and Multiple Stars at ASV and NAO Rozhen in 2017 and 2018
Cvetković, Zorica; Pavlović, Rade; Boeva, Svetlana
We give the results of CCD observations for 789 double or multiple stars obtained during 2017 and 2018. These observations were carried out at both the Serbian Astronomical Station on the mountain of Vidojevica (ASV) and the Bulgarian National Astronomical Observatory at Rozhen (NAOR). They were performed using three telescopes, the 1.4 and 0.6 m …
Probing the Hill Sphere of (486958) 2014 MU69. II. Hubble Space Telescope Fine Guidance Sensors Observations during the 2018 August 4 Stellar Occultation
Stern, S. Alan; Spencer, John R.; Buie, Marc W. +6 more
We observed the 2018 August 4 stellar occultation by the Kuiper Belt object (486958) 2014 MU69, the first close flyby target of the extended New Horizons mission. Rather than capture a solid-body occultation by the KBO itself, our program aimed to constrain the opacity of rings, moons, or other debris in the nearby environment. We used …
Validating the C I 5052.17 Å/Mg II 4481 Å Equivalent Width Ratio as a Diagnostic for F-type Lambda Boo Stars
Cheng, Kwang-Ping; Tarbell, Erik S.; Giacinto, Anthony J. +5 more
The Lambda Boo-type stars are chemically peculiar stars with deficiencies of iron-peak elements but near-solar C, N, O, and S abundances. Since the prototype Lambda Boötis was first reported as peculiar, this group has been expanded from a small group of early A-type stars to a larger group of late B to early F-type dwarfs. Although a detailed abu…
New Variable Stars in NGC 6652 and Its Background Sagittarius Stream
Vivas, A. Katherina; Salinas, Ricardo; Contreras Ramos, Rodrigo
We conducted a variable star search on the metal-rich Galactic globular cluster NGC 6652 using archival Gemini-S/Gemini Multiobject Spectrograph data. We report the discovery of nine new variable stars in the NGC 6652 field, of which we classify six as eclipsing binaries and one as an SX Phoenicis star, leaving two variables without classification…
V348 And and V572 Per: Bright Triple Systems with Eccentric Eclipsing Binaries
Wolf, M.; Uhlař, R.; Zasche, P. +5 more
The eclipsing binaries are still important objects for our understanding of the universe. Especially these ones located within the more complex multiple systems can help us solving the problem of their origin and subsequent evolution of these higher order multiples. Photometry and spectroscopy spanning over more than 25 yr were used for the first …
Upper Limits for Emissions in the Coma of Comet 67P/Churyumov-Gerasimenko near Perihelion as Measured by Rosetta’s Alice Far-UV Spectrograph
Parker, Joel Wm.; Bertaux, Jean-Loup; Stern, S. Alan +13 more
The Alice far-UV imaging spectrograph (700-2050 Å) acquired over 70,000 spectral images during Rosetta’s 2 yr escort mission, including over 20,000 in the months surrounding perihelion when the comet activity level was highest. We have developed automated software to fit and remove ubiquitous H, O, C, S, and CO emissions from Alice spectra, along …
Automatic Detection and Tracking of Plumes from 67P/Churyumov-Gerasimenko in Rosetta/OSIRIS Image Sequences
Sierks, Holger; Thompson, David R.; Brown, David +2 more
Solar system bodies such as comets and asteroids are known to eject material from their surface in the form of jets and plumes. Observations of these transient outbursts can offer insight into the inner workings and makeup of their originating body. However, the detection of and response to these events has thus far been manually controlled by gro…
System Parameters for the Eclipsing B-star Binary BD+11°3569
Gies, Douglas R.; Matson, Rachel A.; Williams, Stephen J. +4 more
We present the results from a combined spectroscopic and photometric in-depth study of the binary system BD+11o3569 (B4 V + B5 V). Fits to Johnson V, Cousins R C and I C photometry, and radial velocities yield an orbital period of 1.49712598 ± 0.00000020 days and an inclination of 82.°93 ± 0.°17. The combined l…
FUSE and IUE Spectroscopy of the Prototype Dwarf Nova ER Ursa Majoris During Quiescence
Sion, Edward M.; Godon, Patrick; Guzman, Giannina
ER Ursae Majoris is the prototype for a subset of SU UMa-type dwarf novae characterized by short cycle times between outburst, high outburst frequency, and negative superhumps. It suffers superoutbursts every 43 days, lasting 20 days, normal outbursts every 4 days, and has an outburst amplitude of 3 mag. We have carried out a far-ultraviolet (FUV)…
Observation, Modern Light-curve Analysis, and 89 yr Period Study of the Short-period Algol, AE Cassiopeia
Caton, Daniel B.; Samec, Ronald G.; Chamberlain, Heather +1 more
AE Cas was observed some 40 yr ago by Srivastava & Kandpal and was analyzed by Kopal’s Fourier frequency -domain technique. No further precision observations have taken place until the present study, which represents the first modern synthetic analysis of light curves using the 2016 version of the Wilson-Devinney (W-D) Program. It was observed…