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The Orbital and Physical Properties of Five Southern Be+sdO Binary Systems
Gies, Douglas R.; Wang, Luqian; Peters, Geraldine J. +1 more
Close binary interactions may play a critical role in the formation of the rapidly rotating Be stars. Mass transfer can result in a mass gainer star spun up by the accretion of mass and angular momentum, while the mass donor is stripped of its envelope to form a hot and faint helium star. Far-UV spectroscopy has led to the detection of about 20 su…
The On-orbit Performance of the Colorado Ultraviolet Transit Experiment Mission
France, Kevin; Fleming, Brian; Nell, Nicholas +5 more
We present the on-orbit performance of the Colorado Ultraviolet Transit Experiment (CUTE). CUTE is a 6U CubeSat that launched on 2021 September 27 and is obtaining near-ultraviolet (NUV; 2480 Å-3306 Å) transit spectroscopy of short-period exoplanets. The instrument comprises a 20 cm × 8 cm rectangular Cassegrain telescope, an NUV spectrograph with…
The Emergence of a Neutral Wind Region in the Orbital Plane of Symbiotic Binaries during Their Outbursts
Skopal, Augustin
Accretion of mass onto a white dwarf (WD) in a binary system can lead to stellar explosions. If a WD accretes from stellar wind of a distant evolved giant in a symbiotic binary, it can undergo occasional outbursts in which it brightens by several magnitudes, produces a low- and high-velocity mass outflow, and, in some cases, ejects bipolar jets. I…
The Mass-Temperature Relation for B and Early A Stars Based on International Ultraviolet Explorer Spectra of Detached Eclipsing Binaries
Torres, Guillermo; Evans, Nancy Remage; Kuraszkiewicz, Joanna +4 more
Ultraviolet spectra were taken of 25 detached eclipsing binaries (DEBs) with spectral types O, B, and early A with the International Ultraviolet Explorer satellite in the 1150-1900 Å region. The spectra were compared with BOSZ model atmospheres. The composite spectra of the DEBs were modeled by a combination of models representing the hot and cool…
Precise Age for the Binary Star System 12 Com in the Coma Berenices Cluster
Klement, Robert; Monnier, John D.; Schaefer, Gail H. +11 more
We present measurements of the interferometrically resolved binary star system 12 Com and the single giant star 31 Com in the cluster Coma Berenices. 12 Com is a double-lined spectroscopic binary system consisting of a G7 giant and an A3 dwarf at the cluster turnoff. Using an extensive radial velocity data set and interferometric measurements from…
The Unexpected Optical and Ultraviolet Variability of the Standard Star α Sex (HD 87887)
Bowman, Dominic M.; Lebreton, Yveline; Monier, Richard +1 more
The analysis of the available Transiting Exoplanet Survey Satellite (TESS) light curves of α Sex (HD 87887) reveals low-frequency pulsations with a period of about 9.1 hr in this spectroscopic A0 III standard star. The IUE observations in 1992 December reveal large flux variations both in the far-UV and in the mid-UV, which are accompanied by vari…
AU Microscopii in the Far-UV: Observations in Quiescence, during Flares, and Implications for AU Mic b and c
France, Kevin; Youngblood, Allison; Gaidos, Eric +13 more
High-energy X-ray and ultraviolet (UV) radiation from young stars impacts planetary atmospheric chemistry and mass loss. The active ~22 Myr M dwarf AU Mic hosts two exoplanets orbiting interior to its debris disk. Therefore, this system provides a unique opportunity to quantify the effects of stellar X-ray and UV irradiation on planetary atmospher…
The Transformative Journey of HD 93521
Gies, Douglas R.; Shepard, Katherine; Klement, Robert +1 more
HD 93521 is a massive, rapidly rotating star that is located about 1 kpc above the Galactic disk, and the evolutionary age for its estimated mass is much less than the time of flight if it was ejected from the disk. Here we present a reassessment of both the evolutionary and kinematical timescales for HD 93521. We calculate a time of flight of 39 …
Multiwavelength Modeling the SED of Luminous Supersoft X-Ray Sources in Large Magellanic Cloud and Small Magellanic Cloud
Skopal, Augustin
Classical supersoft X-ray sources (SSSs) are understood as close binary systems in which a massive white dwarf accretes from its companion at rates sustaining steady hydrogen burning on its surface generating bolometric luminosities of 1036-2 × 1038 erg s-1. Here, we perform for the first time the global supersoft …
The Detection and Characterization of Be+sdO Binaries from HST/STIS FUV Spectroscopy
Gies, Douglas R.; Lester, Kathryn V.; Wang, Luqian +4 more
The B emission-line stars are rapid rotators that were probably spun up by mass and angular momentum accretion through mass transfer in an interacting binary. Mass transfer will strip the donor star of its envelope to create a small and hot subdwarf remnant. Here we report on Hubble Space Telescope/STIS far-ultraviolet spectroscopy of a sample of …