Search Publications
Massive White Dwarfs in Young Star Clusters
Caiazzo, Ilaria; Richer, Harvey B.; Heyl, Jeremy +6 more
We have carried out a search for massive white dwarfs (WDs) in the direction of young open star clusters using the Gaia DR2 database. The aim of this survey was (1) to provide robust data for new and previously known high-mass WDs regarding cluster membership, (2) to highlight WDs previously included in the initial final mass relation (IFMR) that …
Gaia EDR3 Proper Motions of Milky Way Dwarfs. II Velocities, Total Energy, and Angular Momentum
Hammer, Francois; Babusiaux, Carine; Bonifacio, Piercarlo +5 more
Here we show that precise Gaia EDR3 proper motions have provided robust estimates of 3D velocities, angular momentum, and total energy for 40 Milky Way dwarfs. The results are statistically robust and are independent of the Milky Way mass profile. Dwarfs do not behave like long-lived satellites of the Milky Way because of their excessively large v…
Forward Modeling of Solar Coronal Magnetic-field Measurements Based on a Magnetic-field-induced Transition in Fe X
Chen, Yajie; Tian, Hui; Deng, Yuanyong +6 more
It was recently proposed that the intensity ratios of several extreme ultraviolet spectral lines from Fe X ions can be used to measure the solar coronal magnetic field based on magnetic-field-induced transition (MIT) theory. To verify the suitability of this method, we performed forward modeling with a three-dimensional radiation magnetohydrodynam…
Ultra-steep-spectrum Radio "Jellyfish" Uncovered in A2877
Johnston-Hollitt, Melanie; Hodgson, Torrance; Bartalucci, Iacopo +3 more
We report on the discovery of a mysterious ultra-steep-spectrum (USS) synchrotron source in the galaxy cluster A2877. We have observed the source with the Murchison Widefield Array at five frequencies across 72-231 MHz and found the source to exhibit strong spectral curvature over this range, as well as the steepest known spectra of a synchrotron …
Formation of a Solar Filament by Magnetic Reconnection, Associated Chromospheric Evaporation, and Subsequent Coronal Condensation
Yang, Bo; Yang, Jiayan; Bi, Yi +2 more
We present the first observation of a solar filament formed by magnetic reconnection, associated chromospheric evaporation, and subsequent coronal condensation. Driven by shearing motion during flux emergence, a sequential tether-cutting reconnection process occurred and resulted in an M1.3 confined flare accompanied by the formation of a sigmoid …
Revealing Efficient Dust Formation at Low Metallicity in Extragalactic Carbon-rich Wolf-Rayet Binaries
Moffat, Anthony F. J.; Smith, Nathan; Bond, Howard E. +6 more
We present Spitzer/InfraRed Array Camera observations of dust formation from six extragalactic carbon-rich Wolf-Rayet (WC) binary candidates in low-metallicity (Z ≲ 0.65 Z⊙) environments using multiepoch mid-infrared (IR) imaging data from the SPitzer InfraRed Intensive Transients Survey (SPIRITS). Optical follow-up spectroscopy of SPIR…
Transients from the Cataclysmic Deaths of Cataclysmic Variables
Strader, Jay; Chomiuk, Laura; Shen, Ken J. +2 more
We explore the observational appearance of the merger of a low-mass star with a white dwarf (WD) binary companion. We are motivated by recent work finding that multiple tensions between the observed properties of cataclysmic variables (CVs) and standard evolution models are resolved if a large fraction of CV binaries merge as a result of unstable …
A Wide Planetary Mass Companion Discovered through the Citizen Science Project Backyard Worlds: Planet 9
Debes, John H.; Gonzales, Eileen C.; Meisner, Aaron M. +22 more
Through the Backyard Worlds: Planet 9 citizen science project we discovered a late-type L dwarf co-moving with the young K0 star BD+60 1417 at a projected separation of 37″ or 1662 au. The secondary-CWISER J124332.12+600126.2 (W1243)-is detected in both the CatWISE2020 and 2MASS reject tables. The photometric distance and CatWISE proper motion bot…
Flare-forecasting Algorithms Based on High-gradient Polarity Inversion Lines in Active Regions
Piana, Michele; Benvenuto, Federico; Cicogna, Domenico +6 more
Solar flares emanate from solar active regions hosting complex and strong bipolar magnetic fluxes. Estimating the probability of an active region to flare and defining reliable precursors of intense flares are extremely challenging tasks in the space weather field. In this work, we focus on two metrics as flare precursors, the unsigned flux R, tes…
A Layered Debris Disk around M Star TWA 7 in Scattered Light
Stark, Christopher C.; Debes, John H.; Roberge, Aki +15 more
We have obtained Hubble Space Telescope (HST) coronagraphic observations of the circumstellar disk around M star TWA 7 using the Space Telescope Imaging Spectrograph (STIS) instrument in visible light. Together with archival observations, including HST/NICMOS using the F160W filter and Very Large Telescope/SPHERE at the H-band in polarized light, …