Search Publications

Electron Vorticity Indicative of the Electron Diffusion Region of Magnetic Reconnection
DOI: 10.1029/2019GL082710 Bibcode: 2019GeoRL..46.6287H

Russell, C. T.; Khotyaintsev, Y.; Hasegawa, H. +17 more

While vorticity defined as the curl of the velocity has been broadly used in fluid and plasma physics, this quantity has been underutilized in space physics due to low time resolution observations. We report Magnetospheric Multiscale (MMS) observations of enhanced electron vorticity in the vicinity of the electron diffusion region of magnetic reco…

2019 Geophysical Research Letters
Cluster 27
NuSTAR Detection of X-Rays Concurrent with Gamma-Rays in the Nova V5855 Sgr
DOI: 10.3847/1538-4357/aafb6d Bibcode: 2019ApJ...872...86N

Sokoloski, J. L.; Chomiuk, Laura; Mukai, Koji +7 more

We report the first detection of hard (>10 keV) X-ray emission simultaneous with gamma-rays in a nova eruption. Observations of the nova V5855 Sgr carried out with the NuSTAR satellite on Day 12 of the eruption revealed faint, highly absorbed thermal X-rays. The extreme equivalent hydrogen column density toward the X-ray emitting region (∼3 × 1…

2019 The Astrophysical Journal
eHST 27
Smoking gun of the dynamical processing of solar-type field binary stars
DOI: 10.1093/mnras/stz2274 Bibcode: 2019MNRAS.490..550L

Liu, Chao

I investigate the binarity properties of field stars using more than 50 000 main-sequence stars with stellar mass from 0.4 to 0.85 M observed by LAMOST and Gaia in the solar neighbourhood. By adopting a power-law shape for the mass-ratio distribution with a power index of γ, I conduct a hierarchical Bayesian model to derive the binary …

2019 Monthly Notices of the Royal Astronomical Society
Gaia 27
Exploring Plasma Heating in the Current Sheet Region in a Three-dimensional Coronal Mass Ejection Simulation
DOI: 10.3847/1538-4357/ab4ce8 Bibcode: 2019ApJ...887..103R

Reeves, Katharine K.; Mikić, Zoran; Török, Tibor +2 more

We simulate a coronal mass ejection using a three-dimensional magnetohydrodynamic code that includes coronal heating, thermal conduction, and radiative cooling in the energy equation. The magnetic flux distribution at 1 R s is produced by a localized subsurface dipole superimposed on a global dipole field, mimicking the presence of an…

2019 The Astrophysical Journal
Hinode 27
HIDES spectroscopy of bright detached eclipsing binaries from the Kepler field - III. Spectral analysis, updated parameters and new systems
DOI: 10.1093/mnras/sty3528 Bibcode: 2019MNRAS.484..451H

Kambe, E.; Pigulski, A.; Maehara, H. +5 more

We present the latest results of our spectroscopic observations and refined modelling of a sample of detached eclipsing binaries, selected from the Kepler Eclipsing Binary Catalog, that are also double-lined spectroscopic binaries (SB2s). New high-resolution spectra obtained with the HIgh-Dispersion Echelle Spectrograph (HIDES), attached to the 1.…

2019 Monthly Notices of the Royal Astronomical Society
Gaia 27
Observation of a Reversal of Breakout Reconnection Preceding a Jet: Evidence of Oscillatory Magnetic Reconnection?
DOI: 10.3847/1538-4357/ab0c9d Bibcode: 2019ApJ...874..146H

Yang, Bo; Yang, Jiayan; Bi, Yi +3 more

Recent studies have revealed that solar jets involving minifilament eruptions may be initiated under the well-known magnetic-breakout mechanism. Before or just at the onset of those jets, there should be a current sheet, where breakout magnetic reconnection takes place, between open fields and the outside of the jet-base arcade carrying a minifila…

2019 The Astrophysical Journal
IRIS 27
Cloud Atlas: High-contrast Time-resolved Observations of Planetary-mass Companions
DOI: 10.3847/1538-3881/ab037f Bibcode: 2019AJ....157..128Z

Schneider, Glenn; Metchev, Stanimir; Apai, Dániel +11 more

Directly imaged planetary-mass companions offer unique opportunities in atmospheric studies of exoplanets. They share characteristics of both brown dwarfs and transiting exoplanets, and therefore are critical for connecting atmospheric characterizations for these objects. Rotational phase mapping is a powerful technique to constrain the condensate…

2019 The Astronomical Journal
Gaia eHST 27
The JCMT Transient Survey: An Extraordinary Submillimeter Flare in the T Tauri Binary System JW 566
DOI: 10.3847/1538-4357/aaf3b1 Bibcode: 2019ApJ...871...72M

Herczeg, Gregory J.; Johnstone, Doug; Lee, Jeong-Eun +7 more

The binary T Tauri system JW 566 in the Orion Molecular Cloud underwent an energetic, short-lived flare observed at submillimeter wavelengths by the SCUBA-2 instrument on 2016 November 26 (UT). The emission faded by nearly 50% during the 31 minute integration. The simultaneous source fluxes averaged over the observation are 500+/- 107 {mJy} {beam}…

2019 The Astrophysical Journal
Gaia 27
Stellar Properties of Active G and K Stars: Exploring the Connection between Starspots and Chromospheric Activity
DOI: 10.3847/1538-3881/ab2e04 Bibcode: 2019AJ....158..101M

Hawley, Suzanne L.; Agol, Eric; Curtis, Jason L. +2 more

We gathered high resolution spectra for an ensemble of 55 bright active and inactive stars using the ARC 3.5 m Telescope Echelle Spectrograph at Apache Point Observatory (R ≈ 31,500). We measured spectroscopic effective temperatures, surface gravities, and metallicities for most stars in the sample with SME and MOOG. Our stellar property results a…

2019 The Astronomical Journal
Gaia 27
Two Types of Confined Solar Flares
DOI: 10.3847/1538-4357/ab3121 Bibcode: 2019ApJ...881..151L

Hou, Yijun; Li, Ting; Zhang, Jun +1 more

With the aim of understanding the physical mechanisms of confined flares, we selected 18 confined flares during 2011-2017, and first classified them into two types based on their different dynamic properties and magnetic configurations. “Type I” confined flares are characterized by slipping reconnection, strong shear, and a stable filament. “Type …

2019 The Astrophysical Journal
IRIS SOHO 27