Search Publications
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, …
The Nuclear Star Cluster and Nuclear Stellar Disk of the Milky Way: Different Stellar Populations and Star Formation Histories
Neumayer, Nadine; Schödel, Rainer; Nogueras-Lara, Francisco
The Milky Way's nuclear stellar disk (NSD) and nuclear star cluster (NSC) are the main features of the Galactic center. Nevertheless, their observation is hampered by the extreme source crowding and high extinction. Hence, their relation and formation scenario are not fully clear yet. We aim to detect the stellar populations from the NSC and the N…
Disk Masses and Dust Evolution of Protoplanetary Disks around Brown Dwarfs
Espaillat, Catherine C.; Rilinger, Anneliese M.
We present the largest sample of brown dwarf (BD) protoplanetary disk spectral energy distributions modeled to date. We compile 49 objects with ALMA observations from four star-forming regions: ρ Ophiuchus, Taurus, Lupus, and Upper Scorpius. Studying multiple regions with various ages enables us to probe disk evolution over time. Specifically, fro…
The First Retrieval of a Substellar Subdwarf: A Cloud-free SDSS J125637.13-022452.4
Gonzales, Eileen C.; Marley, Mark; Faherty, Jacqueline K. +5 more
We present the first retrieval analysis of a substellar subdwarf, SDSS J125637.13-022452.4 (SDSS J1256-0224), using the Brewster retrieval code base. We find SDSS J1256-0224 is best fit by a cloud-free model with an ion (neutral H, H-, and electron) abundance corresponding to ${\left[\mathrm{Fe}/{\rm{H}}\right]}_{\mathrm{ion}}=-1.5$ . H…
Comparative Analysis of the 2020 November 29 Solar Energetic Particle Event Observed by Parker Solar Probe
Lario, D.; Palmerio, E.; Mitchell, D. G. +15 more
We analyze two specific features of the intense solar energetic particle (SEP) event observed by Parker Solar Probe (PSP) between 2020 November 29 and 2020 December 2. The interplanetary counterpart of the coronal mass ejection (CME) on 2020 November 29 that generated the SEP event (hereafter ICME-2) arrived at PSP (located at 0.8 au from the Sun)…