Search Publications
Eta Carinae: An Evolving View of the Central Binary, Its Interacting Winds and Its Foreground Ejecta
Hamaguchi, Kenji; Corcoran, Michael F.; Russell, Christopher M. P. +13 more
FUV spectra of η Car, recorded across two decades with HST/STIS, document multiple changes in resonant lines caused by dissipating extinction in our line of sight. The FUV flux has increased nearly tenfold, which has led to increased ionization of the multiple shells within the Homunculus and photodestruction of H2. Comparison of observ…
Effect of the Heliospheric State on CME Evolution
Gopalswamy, Nat; Akiyama, Sachiko; Yashiro, Seiji +2 more
The culmination of solar cycle 24 by the end of 2019 has created the opportunity to compare the differing properties of coronal mass ejections (CMEs) between two whole solar cycles: solar cycle 23 (SC 23) and solar cycle 24 (SC 24). We report on the width evolution of limb CMEs in SCs 23 and 24 in order to test the suggestion by Gopalswamy et al. …
Y Gem: A White Dwarf Symbiotic Star?
Wang, Q. Daniel; Shao, Yong; Li, Xiang-Dong +2 more
In this work we conduct a thorough investigation of the X-ray and ultraviolet (UV) properties of Y Gem based on six archival XMM-Newton and Chandra observations to explore the nature of the system. The results show that Y Gem has strong (1032-34 erg s-1) X-ray emission, including a hard (with a maximum emission temperature of…
First Images of the Molecular Gas around a Born-again Star Revealed by ALMA
Treviño-Morales, Sandra P.; Toalá, Jesús A.; Guerrero, Martín A. +7 more
Born-again stars allow probing stellar evolution in human timescales and provide the most promising path for the formation of hydrogen-deficient post-asymptotic giant branch objects, but their cold and molecular components remain poorly explored. Here we present ALMA observations of V 605 Aql that unveil for the first time the spatio-kinematic dis…
Gas and Dust Shadows in the TW Hydrae Disk
Andrews, Sean M.; Bae, Jaehan; Huang, Jane +4 more
We present new observations of CO J = 2 - 1 emission from the protoplanetary disk around TW Hya. Emission is detected out to 240 au (4″) and found to exhibit azimuthal variations up to 20% beyond 180 au (3″), with the west side of the disk brighter than the east. This asymmetry is interpreted as tracing the shadow previously seen in scattered ligh…
The Quantitative Relation of the Time Profiles of Intensities in the Well-connected Solar Energetic Particle Events
Wang, Yang; Lyu, Dan; Qin, Gang +1 more
In this work, the quantitative relation of the intensity time profiles in the well-connected energetic particle events has been identified. Focusing on the propagation processes of energetic protons in the energy channels of about 13-64 MeV, solar energetic particle (SEP) events observed by STEREO A, STEREO B, and SOHO have been studied. The inten…
Determination of Sodium Abundance Ratio from Low-resolution Stellar Spectra and Its Applications
Koo, Jae-Rim; Beers, Timothy C.; Lee, Young Sun +2 more
We present a method to determine sodium abundance ratios ([Na/Fe]) using the Na I D doublet lines in low-resolution (R ~ 2000) stellar spectra. As stellar Na I D lines are blended with those produced by the interstellar medium, we developed a technique for removing the interstellar Na I D lines using the relationship between extinction, which is p…
Contribution of Spicules to Solar Coronal Emission
Klimchuk, James A.; Sarkar, Aveek; Sow Mondal, Shanwlee
Recent high-resolution imaging and spectroscopic observations have generated renewed interest in spicules' role in explaining the hot corona. Some studies suggest that some spicules, often classified as type II, may provide significant mass and energy to the corona. Here we use numerical simulations to investigate whether such spicules can produce…
Kinematical Analysis of Substructure in the Southern Periphery of the Large Magellanic Cloud
Monachesi, Antonela; Choi, Yumi; Majewski, Steven R. +10 more
We report the first 3D kinematical measurements of 88 stars in the direction of several recently discovered substructures in the southern periphery of the Large Magellanic Cloud (LMC) using a combination of Gaia proper motions and radial velocities from the APOGEE-2 survey. More specifically, we explore stars in assorted APOGEE-2 pointings in a re…
Radiative Magnetohydrodynamic Simulation of the Confined Eruption of a Magnetic Flux Rope: Magnetic Structure and Plasma Thermodynamics
Ding, Mingde; Chen, Feng; Wang, Can +1 more
It is widely believed that magnetic flux ropes are the key structure of solar eruptions; however, their observable counterparts are not clear yet. We study a flare associated with flux rope eruption in a comprehensive radiative magnetohydrodynamic simulation of flare-productive active regions, especially focusing on the thermodynamic properties of…