Search Publications
Spectroscopic and photometric study for five late G- to K-type short-period contact binaries
Michel, Raúl; Mora Zamora, I.; Wang, Zhi-Hua +1 more
We reported spectroscopy and photometry for five ultra-short period W UMa-type contact binaries. Eleven sets of low resolution spectra are obtained from the Large Sky Area Multiobject Fiber Spectroscopic Telescope (LAMOST) database and analyzed. It has been determined that these systems are late G- to K-type stars: G7V for J0658, G9V for LINEAR 35…
Long-term X-Ray Variability on the Benchmark YSO HL Tau
Schneider, P. C.; Kastner, Joel H.; Principe, David A. +4 more
HL Tau is one of the most well-studied Class I young stellar objects (YSOs), including frequent observations at near- and mid-infrared, (sub)millimeter, and X-ray wavelengths. We present the results of an X-ray variability monitoring campaign with XMM-Newton in 2020 and X-ray grating spectroscopy from Chandra/HETGS in 2018. We find that the X-ray …
Characterizing planetary material accreted by cool helium-atmosphere white dwarfs using an exponentially decaying disc model
Melis, Carl; Klein, Beth L.; Veras, Dimitri +5 more
We present Keck High Resolution Echelle Spectrometer observations and model atmosphere analysis for two nearby, cool, helium-dominated atmosphere white dwarfs that have been polluted by accretion: WD J1927-0355 and WD J2141-3300. Detected elements common to both white dwarfs are Mg, Ca, Ti, Cr, Fe, and Ni, with additional detections of Na, Al, Si,…
The Eclipsing Binaries via Artificial Intelligence. II. Need for Speed in PHOEBE Forward Models
Wrona, Marcin; Prša, Andrej
In modern astronomy, the quantity of data collected has vastly exceeded the capacity for manual analysis, necessitating the use of advanced artificial intelligence (AI) techniques to assist scientists with the most labor-intensive tasks. AI can optimize simulation codes where computational bottlenecks arise from the time required to generate forwa…
Observations of Small-Scale Magnetic Flux Ropes Associated With Significant Values of Partial Variance Increment Indices
Hu, Qiang; Chen, Yu
We report recent findings for the magnetic field configurations of small-scale magnetic flux ropes (SFRs) broadly defined and identified by using the Grad-Shafranov-based techniques for in situ measurements via the Parker Solar Probe (PSP), Solar Orbiter (SolO), and two Helios spacecraft. Since the current sheets were found to occur at boundaries …
A Be star that turned bright and blue during a major outburst
Wang, Wei; Rivinius, Thomas; Baade, Dietrich +16 more
Context. Classical Be stars are rapidly rotating B-type stars exhibiting Balmer emission lines originating from circumstellar Keplerian gaseous disks, which likely form through episodic mass-ejection events. The currently favored model for Be star disks is the viscous decretion disk (VDD) model. However, the mechanism behind the mass ejection proc…
Can Active Galactic Nuclei Activity Be Enhanced by Ram Pressure Stripping?—X-Ray Perspective
Fossati, Matteo; Tiwari, Juhi; Sun, Ming +3 more
Ram pressure stripping (RPS) is an important process that plays a significant role in shaping the evolution of cluster galaxies and their surrounding environment. Despite its recognized significance, the potential connection between RPS and active galactic nuclei (AGN) activity in cluster galaxies remains poorly understood. Recent claims, based on…
Searching for Galactic red supergiants with Gaia RVS spectra
Yang, Ming; Ren, Yi; Jiang, Biwei +2 more
Red supergiants (RSGs) are essential to understanding the evolution and the contribution to the interstellar medium of massive stars. However, the number of identified RSGs within the Milky Way is still limited, mainly due to the difficulty of measuring stellar extinction and distance. The release of approximately one million RVS spectra in Gaia D…
Stellar atmospheric parameters and chemical abundances of ~5 million stars from S-PLUS multiband photometry
Mendes de Oliveira, C.; Placco, V. M.; Borges Fernandes, M. +30 more
Context. The APOGEE, GALAH, and LAMOST spectroscopic surveys have substantially contributed to our understanding of the Milky Way by providing a wide range of stellar parameters and chemical abundances. Complementing these efforts, photometric surveys that include narrowband and medium-band filters, such as Southern Photometric Local Universe Surv…
Near-ultraviolet absorption distribution of primitive asteroids from photometric surveys: II. Collisional families
Tatsumi, Eri; Vilas, Faith; de León, Julia +5 more
Context. Primitive asteroids consisting of mainly phyllosilicates and opaque minerals have great variation at near-ultraviolet (NUV) wavelengths (0.35–0.5 µm). The absorption in NUV could be indicative of phyllosilicates that reflect their formation environments such as the distribution of water, temperature, and pressure. The asteroid colli…