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TIC 435850195: The Second Triaxial Tidally Tilted Pulsator
Rappaport, Saul A.; Gagliano, Robert; Jayaraman, Rahul +8 more
The Transiting Exoplanet Survey Satellite (TESS) has enabled the discovery of numerous tidally tilted pulsators (TTPs), which are pulsating stars in close binaries where the presence of a tidal bulge has the effect of tilting the primary star's pulsation axes into the orbital plane. Recently, the modeling framework developed to analyze TTPs has be…
Expanding the Ultracompacts: Gravitational-wave-driven Mass Transfer in the Shortest-period Binaries with Accretion Disks
Kulkarni, S. R.; Rappaport, Saul A.; Riddle, Reed +35 more
We report the discovery of three ultracompact binary white dwarf systems hosting accretion disks, with orbital periods of 7.95, 8.68, and 13.15 minutes. This significantly augments the population of mass-transferring binaries at the shortest periods, and provides the first evidence that accretors in ultracompacts can be dense enough to host accret…
Tests of Disk-locking in T Tauri Stars of the Orion Nebula Cluster
Dixon, Don M.; Stassun, Keivan G.; Johns-Krull, Christopher M. +1 more
We look for specific correlations predicted by magnetospheric accretion models for young stars that assume disk-locking using stellar and accretion parameters derived from low-resolution HST-STIS spectra of 33 T Tauri stars in the Orion Nebula Cluster. Our results provide strong support for the correlation predicted by a model that does not constr…
Analysis of the Full Spitzer Microlensing Sample. I. Dark Remnant Candidates and Gaia Predictions
Han, Cheongho; Udalski, Andrzej; Lee, Chung-Uk +70 more
In the pursuit of understanding the population of stellar remnants within the Milky Way, we analyze the sample of ∼950 microlensing events observed by the Spitzer Space Telescope between 2014 and 2019. In this study we focus on a subsample of nine microlensing events, selected based on their long timescales, small microlensing parallaxes, and join…
Ba Enrichment in Gaia MS+WD Binaries: Tracing s-process Element Production
Hallakoun, Na'ama; Toonen, Silvia; Rix, Hans-Walter +3 more
A large population of intermediate-separation binaries, consisting of a main-sequence (MS) star and a white dwarf (WD), recently emerged from Gaia's third data release (DR3), posing challenges to current models of binary evolution. Here we examine the s-process element abundances in these systems using data from GALAH DR3. Following refined sample…
Galactic-Seismology Substructures and Streams Hunter with LAMOST and Gaia. I. Methodology and Local Halo Results
Ting, Yuan-Sen; Bland-Hawthorn, Joss; Wang, Hai-Feng +4 more
We present a novel, deep-learning-based method—dubbed Galactic-Seismology Substructures and Streams Hunter, or GS3 Hunter for short—to search for substructures and streams in stellar kinematics data. GS3 Hunter relies on a combined application of Siamese neural networks to transform the phase space information and the K-means…
Probing the Nature of Rotation in the Pleiades, Alpha Persei, and Hyades Clusters
Hao, C. J.; Xu, Y.; Hou, L. G. +5 more
Unraveling the internal kinematics of open clusters is crucial for understanding their formation and evolution. However, there is a dearth of research on this topic, primarily due to the lack of high-quality kinematic data. Using the exquisite-precision astrometric parameters and radial velocities provided by Gaia data release 3, we investigate th…
Discovery of a Proto–White Dwarf with a Massive Unseen Companion
Hermes, J. J.; Zakamska, Nadia L.; El-Badry, Kareem +8 more
We report the discovery of SDSS J022932.28+713002.7, a nascent extremely low-mass (ELM) white dwarf (WD) orbiting a massive (>1 M ⊙ at 2σ confidence) companion with a period of 36 hr. We use a combination of spectroscopy, including data from the ongoing fifth-generation Sloan Digital Sky Survey (SDSS-V), and photometry to measure the…
The Clearing Timescale for Infrared-selected Star Clusters in M83 with HST
Calzetti, Daniela; Johnson, Kelsey E.; Sabbi, Elena +6 more
We present an analysis of Hubble Space Telescope data from Wide Field Camera 3 (WFC3)/Ultraviolet Imaging Spectrometer, WFC3/IR, and the Advanced Camera for Surveys, investigating the young stellar cluster (YSC) population in the face-on spiral galaxy M83. Within the field of view of the IR pointings, we identify 454 sources with compact F814W con…
Relative Yield of Thermal and Nonthermal Emission during Weak Flares Observed by STIX during 2021 September 20–25
Awasthi, Arun Kumar; Mrozek, Tomasz; Kołomański, Sylwester +3 more
The disparate nature of the thermal–nonthermal energy partition during flares, particularly during weak flares, is still an open issue. Following the Neupert effect, quantifying the relative yield of X-ray emission in different energy bands can enable the inferring of the underlying energy release mechanism. During 2021 September 20–25, the Solar …