Search Publications
A Large and Pristine Sample of Standard Candles across the Milky Way: ∼100,000 Red Clump Stars with 3% Contamination
Ting, Yuan-Sen; Rix, Hans-Walter; Hawkins, Keith
Core helium-burning red clump (RC) stars are excellent standard candles in the Milky Way. These stars may have more precise distance estimates from spectrophotometry than from Gaia parallaxes beyond 3 kpc. However, RC stars have values of T eff and {log}g that are very similar to some red giant branch (RGB) stars. Especially for low-res…
Reconciling Observed and Simulated Stellar Halo Masses
Faucher-Giguère, Claude-André; Hopkins, Philip F.; Wetzel, Andrew +6 more
We use cosmological hydrodynamical simulations of Milky Way-mass galaxies from the FIRE project to evaluate various strategies for estimating the mass of a galaxy’s stellar halo from deep, integrated-light images. We find good agreement with integrated-light observations if we mimic observational methods to measure the mass of the stellar halo by …
Characterizing Accreting Double White Dwarf Binaries with the Laser Interferometer Space Antenna and Gaia
Larson, Shane L.; Breivik, Katelyn; Kremer, Kyle +3 more
We demonstrate a method to fully characterize mass-transferring double white dwarf (DWD) systems with a helium-rich (He) white dwarf (WD) donor based on the mass-radius (M-R) relationship for He WDs. Using a simulated Galactic population of DWDs, we show that donor and accretor masses can be inferred for up to ∼60 systems observed by both Laser In…
Gaia 17bpi: An FU Ori-type Outburst
Naylor, Tim; Mainzer, Amy K.; Hillenbrand, Lynne A. +7 more
We report on the source Gaia 17bpi and identify it as a new, ongoing FU Ori-type outburst, associated with a young stellar object. The optical light curve from Gaia exhibited a 3.5 mag rise with the source appearing to plateau in mid-/late 2018. Mid-infrared observations from NEOWISE also show a >3 mag rise that occurred in two stages, with the…
Larger Mutual Inclinations for the Shortest-period Planets
Winn, Joshua N.; Dai, Fei; Masuda, Kento
The Kepler mission revealed a population of compact multiple-planet systems with orbital periods shorter than a year, and occasionally even shorter than a day. By analyzing a sample of 102 Kepler and K2 multiple-planet systems, we measure the minimum difference ΔI between the orbital inclinations, as a function of the orbital distance of the inner…
Old, Metal-poor Extreme Velocity Stars in the Solar Neighborhood
Bell, Eric F.; Hattori, Kohei; Roederer, Ian U. +1 more
We report the discovery of 30 stars with extreme space velocities (≳480 {km} {{{s}}}-1) in the Gaia-DR2 archive. These stars are a subset of 1743 stars with high-precision parallax, large tangential velocity (v tan > 300 {km} {{{s}}}-1), and measured line-of-sight velocity in DR2. By tracing the orbits of the st…
Streamer-blowout Coronal Mass Ejections: Their Properties and Relation to the Coronal Magnetic Field Structure
Vourlidas, Angelos; Webb, David F.
We present a comprehensive analysis of a particular class of coronal mass ejection (CME) event called streamer-blowout CMEs (SBOs). The events are characterized by a gradual swelling of the overlying streamer, lasting hours to days, followed by a slow, wide CME, generally exhibiting a three-part structure, which leaves the streamer significantly d…
Polar Dust, Nuclear Obscuration, and IR SED Diversity in Type-1 AGNs
Lyu, Jianwei; Rieke, George H.
Despite the hypothesized similar face-on viewing angles, the infrared emission of type-1 active galactic nuclei (AGNs) has diverse spectral energy distribution (SED) shapes that deviate substantially from the well-characterized quasar templates. Motivated by the commonly seen UV-optical obscuration and the discovery of parsec-scale mid-IR polar du…
Statistics of Coronal Dimmings Associated with Coronal Mass Ejections. I. Characteristic Dimming Properties and Flare Association
Temmer, M.; Veronig, A. M.; Vanninathan, K. +2 more
Coronal dimmings, localized regions of reduced emission in the extreme-ultraviolet and soft X-rays (SXRs), are interpreted as density depletions due to mass loss during the coronal mass ejection (CME) expansion. They contain crucial information on the early evolution of CMEs low in the corona. For 62 dimming events, characteristic parameters are d…
HAZMAT. IV. Flares and Superflares on Young M Stars in the Far Ultraviolet
Loyd, R. O. Parke; Peacock, Sarah; Meadows, Victoria S. +4 more
M stars are powerful emitters of far-ultraviolet light. Over long timescales, a significant, possibly dominant, fraction of this emission is produced by stellar flares. Characterizing this emission is critical to understanding the atmospheres of the stars producing it and the atmospheric evolution of the orbiting planets subjected to it. Ultraviol…