Search Publications
Hot Subdwarf Stars Identified in Gaia DR2 with Spectra of LAMOST DR6 and DR7. I. Single-lined Spectra
Zhao, Gang; Németh, Péter; Zhao, Jingkun +1 more
182 single-lined hot subdwarf stars are identified by using spectra from the sixth and seventh data releases (DR6 and DR7) of the Large Sky Area Multi-Object Fibre Spectroscopic Telescope survey. We classified all the hot subdwarf stars using a canonical classification scheme, and got 89 sdB, 37 sdOB, 26 sdO, 24 He-sdOB, 3 He-sdO, and 3 He-sdB sta…
An Exact, Generalized Laplace Resonance in the HR 8799 Planetary System
Goździewski, Krzysztof; Migaszewski, Cezary
A system of four super-Jupiter planets around HR 8799 is the first multiplanet configuration discovered via the direct imaging technique. Despite over a decade of research, the system's architecture is still not fully resolved. The main difficulty comes from a still narrow observing window of ∼20 yr that covers small arcs of orbits with periods fr…
Mapping the Escape Fraction of Ionizing Photons Using Resolved Stars: A Much Higher Escape Fraction for NGC 4214
Skillman, Evan D.; Williams, Benjamin F.; Gordon, Karl D. +6 more
We demonstrate a new method for measuring the escape fraction of ionizing photons using Hubble Space Telescope imaging of resolved stars in NGC 4214, a local analog of high-redshift starburst galaxies that are thought to be responsible for cosmic reionization. Specifically, we forward model the UV through near-IR spectral energy distributions of ∼…
Spitzer + VLTI-GRAVITY Measure the Lens Mass of a Nearby Microlensing Event
Feliz, Dax L.; Zang, Weicheng; Gould, Andrew +26 more
We report the lens mass and distance measurements of the nearby microlensing event TCP J05074264+2447555 (Kojima-1). We measure the microlens parallax vector ${{\boldsymbol{\pi }}}_{{\rm{E}}}$ using Spitzer and ground-based light curves with constraints on the direction of lens-source relative proper motion derived from Very Large Telescope Interf…
Hunting for Runaways from the Orion Nebula Cluster
Tan, Jonathan C.; Eyer, Laurent; Farias, Juan P.
We use Gaia DR2 to hunt for runaway stars from the Orion Nebula Cluster (ONC). We search a region extending 45° around the ONC and out to 1 kpc to find sources that have overlapped in angular position with the cluster in the last ∼10 Myr. We find ∼17,000 runaway/walkaway candidates that satisfy this 2D traceback condition. Most of these are expect…
Characterization of Temporarily Captured Minimoon 2020 CD3 by Keck Time-resolved Spectrophotometry
Duev, Dmitry A.; Riddle, Reed; Ip, Wing-Huen +42 more
We present time-resolved visible spectrophotometry of 2020 CD3, the second known minimoon. The spectrophotometry was taken with the Keck I/Low Resolution Imaging Spectrometer between wavelengths 434 and 912 nm in the B, g, V, R, I, and RG850 filters as it was leaving the Earth-Moon system on 2020 March 23 UTC. The spectrum of 2020 CD
The Hidden Past of M92: Detection and Characterization of a Newly Formed 17° Long Stellar Stream Using the Canada-France Imaging Survey
Jensen, Jaclyn; Navarro, Julio F.; Cuillandre, Jean-Charles +17 more
We present an analysis of the structure, kinematics, and orbit of a newly found stellar stream emanating from the globular cluster M92 (NGC 6341). This stream was discovered in an improved matched-filter map of the outer Galaxy, based on a "color-color-magnitude" diagram, created using photometry from the Canada-France Imaging Survey and the Pan-S…
Irregular Dust Features around Intermediate-mass Young Stars with GPI: Signs of Youth or Misaligned Disks?
Monnier, John D.; Kraus, Stefan; Hinkley, Sasha +14 more
We are undertaking a large survey of over 30 disks using the Gemini Planet Imager (GPI) to see whether the observed dust structures match spectral energy distribution predictions and have any correlation with stellar properties. GPI can observe near-infrared light scattered from dust in circumstellar environments using high-resolution Polarimetric…
Onset of Turbulent Fast Magnetic Reconnection Observed in the Solar Atmosphere
Chitta, L. P.; Lazarian, A.
Fast magnetic reconnection powers explosive events throughout the universe, from gamma-ray bursts to solar flares. Despite its importance, the onset of astrophysical fast reconnection is the subject of intense debate and remains an open question in plasma physics. Here we report high-cadence observations of two reconnection-driven solar microflare…
A Tidal Disruption Event Candidate Discovered in the Active Galactic Nucleus SDSS J022700.77-042020.6
Lu, Youjun; Liu, Zhu; Yuan, Weimin +4 more
We report the discovery of a tidal disruption event (TDE) candidate occurring in the active galactic nucleus (AGN) SDSS J022700.77-042020.6. A sudden increase in flux from J0227-0420 during the second half of 2009 appears in the long-term optical, UV, and near-IR (NIR) light curves. A plateau phase, following an initial decline, is seen in the nea…