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OGLE-BLAP-009 -- A Case Study for the Properties and Evolution of Blue Large-Amplitude Pulsators
Corey W. Bradshaw, Matti Dorsch, Thomas Kupfer +5
Blue large-amplitude pulsators (BLAPs) make up a rare class of hot pulsating stars with effective temperatures of 30,000 K and surface gravities of 4.0 - 5.0 dex (cgs). Th…
Electromagnetic characterization of the LISA verification binary ZTF J05265934
Alekzander Kosakowski, Thomas Kupfer, P. Bergeron +1
We present an analysis of new and archival data to the 20.506-minute LISA verification binary J052610.42593445.32 (J05265934). Our joint spectroscopic and photometric analysi…
LISA Galactic binaries with astrometry from Gaia DR3
Thomas Kupfer, Valeriya Korol, Tyson B. Littenberg +11
Galactic compact binaries with orbital periods shorter than a few hours emit detectable gravitational waves at low frequencies. Their gravitational wave signals can be detected wit…
New Variable Hot Subdwarf Stars Identified from Anomalous Gaia Flux Errors, Observed by TESS, and Classified via Fourier Diagnostics
Brad N. Barlow, Kyle A. Corcoran, Isabelle M. Parker +7
Hot subdwarf stars are mostly stripped red giants that can exhibit photometric variations due to stellar pulsations, eclipses, the reflection effect, ellipsoidal modulation, and Do…
Discovery of a double detonation thermonuclear supernova progenitor
Thomas Kupfer, Evan B. Bauer, Jan van Roestel +12
We present the discovery of a new double detonation progenitor system consisting of a hot subdwarf B (sdB) binary with a white dwarf companion with an P=76.34179(2) min orbital per…
A hot subdwarf-white dwarf super-Chandrasekhar candidate supernova Ia progenitor
Ingrid Pelisoli, P. Neunteufel, S. Geier +8
Supernova Ia are bright explosive events that can be used to estimate cosmological distances, allowing us to study the expansion of the Universe. They are understood to result from…
Phases of Mass Transfer from Hot Subdwarfs to White Dwarf Companions and Their Photometric Properties
Evan B. Bauer, Thomas Kupfer
Binary systems of a hot subdwarf B (sdB) star + a white dwarf (WD) with orbital periods less than 2-3 hours can come into contact due to gravitational waves and transfer mass from…
ZTFJ0038+2030: a long period eclipsing white dwarf and a substellar companion
Jan van Roestel, Thomas Kupfer, Keaton J. Bell +11
In a search for eclipsing white dwarfs using the Zwicky Transient Facility lightcurves, we identified a deep eclipsing white dwarf with a dark, substellar companion. The lack of an…
A systematic search for outbursting AM CVn systems with the Zwicky Transient Facility
Jan van Roestel, Leah Creter, Thomas Kupfer +15
AM CVn systems are a rare type of accreting binary that consists of a white dwarf and a helium-rich, degenerate donor star. Using the Zwicky Transient Facility (ZTF), we searched f…
Year 1 of the ZTF high-cadence Galactic Plane Survey: Strategy, goals, and early results on new single-mode hot subdwarf B-star pulsators
Thomas Kupfer, Thomas A. Prince, Jan van Roestel +18
We present the goals, strategy and first results of the high-cadence Galactic plane survey using the Zwicky Transient Facility (ZTF). The goal of the survey is to unveil the Galact…
HO Puppis: Not a Be Star but a Newly Confirmed IW And-Type Star
Chien-De Lee, Jia-Yu Ou, Po-Chieh Yu +19
HO Puppis (HO Pup) was considered as a Be-star candidate based on its gamma-Cassiopeiae-type light curve, but lacked spectroscopic confirmation. Using distance measured from Gaia D…
The luminous red nova AT 2018bwo in NGC 45 and its binary yellow supergiant progenitor
Nadejda Blagorodnova, Jakub Klencki, Ondrej Pejcha +12
Luminous Red Novae (LRNe) are astrophysical transients associated with the partial ejection of a binary system's common envelope (CE) shortly before its merger. Here we present the…
An Outburst by AM CVn binary SDSS J113732.32+405458.3
Tin Long Sunny Wong, Jan van Roestel, Thomas Kupfer +1
We report the discovery of a one magnitude increase in the optical brightness of the 59.63 minute orbital period AM CVn binary SDSS J113732.32+405458.3. Public , , and ba…
EVR-CB-004: An Inflated Hot Subdwarf O star + Unseen WD Companion in a Compact Binary Discovered with the Evryscope
Jeffrey K. Ratzloff, Thomas Kupfer, Brad N. Barlow +10
We present the discovery of EVR-CB-004, a close binary with a remnant stellar core and an unseen white dwarf companion. The analysis in this work reveals the primary is potentially…
A systematic search of Zwicky Transient Facility data for ultracompact binary LISA-detectable gravitational-wave sources
Kevin B. Burdge, Thomas A. Prince, Jim Fuller +31
Using photometry collected with the Zwicky Transient Facility (ZTF), we are conducting an ongoing survey for binary systems with short orbital periods ( with…
A new class of Roche lobe-filling hot subdwarf binaries
Thomas Kupfer, Evan B. Bauer, Kevin B. Burdge +30
We present the discovery of the second binary with a Roche lobe-filling hot subdwarf transferring mass to a white dwarf (WD) companion. This 56 minute binary was discovered using d…
A Search for Extra-Tidal RR Lyrae in the Globular Cluster NGC 5024 and NGC 5053
Chow-Choong Ngeow, Justin Belecki, Rick Burruss +9
Recently, Kundu et al (2019) reported that the globular cluster NGC 5024 (M53) possesses five extra-tidal RR Lyrae. In fact, four of them were instead known members of a nearby glo…
Cataclysmic Variables in the First Year of the Zwicky Transient Facility
Paula Szkody, Brooke Dicenzo, Anna Y. Q. Ho +25
Using selection criteria based on amplitude, time and color, we have identified 329 objects as known or candidate cataclysmic variable (CVs) during the first year of testing and op…
The first ultracompact Roche lobe-filling hot subdwarf binary
Thomas Kupfer, Evan B. Bauer, Thomas R. Marsh +29
We report the discovery of the first short period binary in which a hot subdwarf star (sdOB) fills its Roche lobe and started mass transfer to its companion. The object was discove…
Orbital Decay in a 20 Minute Orbital Period Detached Binary with a Hydrogen Poor Low Mass White Dwarf
Kevin B Burdge, Jim Fuller, E. Sterl Phinney +14
We report the discovery of a detached double white dwarf binary with an orbital period of , PTF J053332.05+020911.6. The visible object in this binary, PT…
EVR-CB-001: An evolving, progenitor, white dwarf compact binary discovered with the Evryscope
Jeffrey K. Ratzloff, Brad N. Barlow, Thomas Kupfer +7
We present EVR-CB-001, the discovery of a compact binary with an extremely low mass () helium core white dwarf progenitor (pre-He WD) and an unseen low mass…
Variability of massive stars in M31 from the Palomar Transient Factory
Monika D. Soraisam, Lars Bildsten, Maria R. Drout +5
Using data from the (intermediate) Palomar Transient Factory (iPTF), we characterize the time variability of ~500 massive stars in M31. Our sample is those stars which are spectral…
General relativistic orbital decay in a seven-minute-orbital-period eclipsing binary system
Kevin B. Burdge, Michael W. Coughlin, Jim Fuller +23
General relativity predicts that short orbital period binaries emit significant gravitational radiation, and the upcoming Laser Interferometer Space Antenna (LISA) is expected to d…
Variability of Red Supergiants in M31 from the Palomar Transient Factory
Monika D. Soraisam, Lars Bildsten, Maria R. Drout +9
Most massive stars end their lives as Red Supergiants (RSGs), a short-lived evolution phase when they are known to pulsate with varying amplitudes. The RSG period-luminosity (PL) r…