Search Publications
White Dwarf Photospheric Abundances in Cataclysmic Variables-II. White Dwarfs with and without a Mask
Sion, Edward M.; Godon, Patrick
Taking advantage of the now-available Gaia EDR3 parallaxes, we carry out an archival Hubble Space Telescope (HST) far-ultraviolet spectroscopic analysis of 10 cataclysmic variable systems, including five carefully selected eclipsing systems. We obtain accurate white dwarf (WD) masses and temperatures, in excellent agreement with the masses for fou…
Homologous Compact Major Blowout-eruption Solar Flares and their Production of Broad CMEs
Joshi, Bhuwan; Moore, Ronald L.; Sterling, Alphonse C. +2 more
We analyze the formation mechanism of three homologous broad coronal mass ejections (CMEs) resulting from a series of solar blowout-eruption flares with successively increasing intensities (M2.0, M2.6, and X1.0). The flares originated from NOAA Active Region 12017 during 2014 March 28-29 within an interval of ≈24 hr. Coronal magnetic field modelin…
Data-driven Derivation of Stellar Properties from Photometric Time Series Data Using Convolutional Neural Networks
Angus, Ruth; Huber, Daniel; Ness, Melissa K. +2 more
Stellar variability is driven by a multitude of internal physical processes that depend on fundamental stellar properties. These properties are our bridge to reconciling stellar observations with stellar physics and to understand the distribution of stellar populations within the context of galaxy formation. Numerous ongoing and upcoming missions …
Investigating the Accretion Nature of Binary Supermassive Black Hole Candidate SDSS J025214.67-002813.7
Shi, Fangzheng; Gültekin, Kayhan; Chen, Yu-Ching +3 more
We present results of a multiwavelength analysis of SDSS J025214.67-002813.7, a system that has been previously classified as a binary active galactic nucleus (AGN) candidate based on periodic signals detected in the optical light curves. We use available radio-X-ray observations of the system to investigate the true accretion nature. Analyzing ne…
Three-dimensional Magnetic and Thermodynamic Structures of Solar Microflares
Cheng, X.; Ding, M. D.; Chen, J. +2 more
Microflares, one of the small-scale solar activities, are believed to be caused by magnetic reconnection. Nevertheless, their three-dimensional (3D) magnetic structures, thermodynamic structures, and physical links to reconnection are unclear. In this Letter, based on a high-resolution 3D radiative magnetohydrodynamic simulation of the quiet Sun s…
Ice Features of Low-luminosity Protostars in Near-infrared Spectra of AKARI/IRC
Choi, Minho; Lee, Jeong-Eun; Dunham, Michael M. +8 more
We present near-infrared spectra of three low-luminosity protostars and one background star in the Perseus molecular cloud, acquired using the infrared camera on board the AKARI space telescope. For the comparison with different star-forming environments, we also present spectra of the massive protostar AFGL 7009S, where the protostellar envelope …
A Multiwavelength Study of the Sgr B Region: Contiguous Cloud-Cloud Collisions Triggering Widespread Star Formation Events?
Fukui, Yasuo; Enokiya, Rei
The Sgr B region, including Sgr B1 and Sgr B2, is one of the most active star-forming regions in the Galaxy. Hasegawa et al. originally proposed that Sgr B2 was formed by a cloud-cloud collision (CCC) between two clouds with velocities of ~45 km s-1 and ~75 km s-1. However, some recent observational studies conflict with this…
Call and Response: A Time-resolved Study of Chromospheric Evaporation in a Large Solar Flare
Milligan, Ryan O.; McAteer, R. T. James; Sellers, Sean G.
We studied an X1.6 solar flare produced by NOAA Active Region 12602 on 2014 October 22. The entirety of this event was covered by RHESSI, IRIS, and Hinode/EIS, allowing analysis of the chromospheric response to a nonthermal electron driver. We derived the energy contained in nonthermal electrons via RHESSI spectral fitting and linked the time-depe…
The Effect of Light Deflection by Solar System Objects on High-precision Square Kilometre Array Astrometry
Xu, Ye; Hao, Chaojie; Li, Yingjie +4 more
We have computed the deflection angles caused by 195 objects in the solar system, including 177 satellites, and eight asteroids; 21 satellites and six asteroids can bend light from distant compact extragalactic sources by more than 0.1 µas, and 14 satellites, and the asteroid Ceres can deflect light by more than 1.0 µas. We calculated …
Detection of a Broad 8 µm UIR Feature in the Mid-infrared Spectrum of WR 125 Observed with Subaru/COMICS
Onaka, Takashi; Sakon, Itsuki; Williams, Peredur M. +3 more
We present the detection of a broad 8 µm feature in newly formed dust around the carbon-rich Wolf-Rayet (WC) binary WR 125 from N-band low-resolution (NL; R ~ 250) spectroscopy between 7.3 and 13.6 µm and N-band (11.7 µm) and Q-band (18.8 µm) imaging with Subaru/COMICS in 2019 October. WR 125 is a colliding-wind binary (WC7…