Results 121 to 130 of about 17,719 (230)

Determining the Nature of IC 10 X-2: A Comprehensive Study of the Optical/IR Emission from an Extragalactic BeHMXB

The Astrophysical Journal
We present a comprehensive analysis of the optical and infrared (IR) properties of high-mass X-ray binary (HMXB) IC 10 X-2, classified as a supergiant HMXB and superfast X-ray transient by previous work.
Jwaher Alnaqbi, Joseph D. Gelfand, Payaswini Saikia, Craig Heinke, M. C. Baglio, David M. Russell, Guobao Zhang, Antonios Manousakis, Ivan Yu. Katkov, Fraser Lewis   +9 more
doaj   +1 more source

Chandra and XMM-Newton X-ray Observations of the Hyperactive T Tauri Star RY Tau

, 2016
We present results of pointed X-ray observations of the accreting jet-driving T Tauri star RY Tau using Chandra and XMM-Newton. We obtained high-resolution grating spectra and excellent-quality CCD spectra and light curves with the objective of ...
Audard, Marc, Guedel, Manuel, Skinner, Stephen L.   +2 more
core   +1 more source

Ionospheric Characterization Over Iran Using Multi‐Frequency IMB HF Transmitters and Global WSPRNET Reception During the 12 November 2025 Geomagnetic Storm

Space Weather, Volume 24, Issue 6, June 2026.
Abstract The Ionospheric Monitoring Beacon network in Iran provides continuous, multi‐frequency high‐frequency (HF) transmissions using WSPRNET modulation, enabling global reception and near–real‐time monitoring of ionospheric propagation conditions.
A. Mahmoudian, Saba Hafizi Lotfabadi, Mohammad Azimi   +2 more
wiley   +1 more source

The Sun as an X-ray star

Astronomy & Astrophysics
Context. Stellar coronae are unresolved in X-rays, so inferences about their structure rely on spectral analysis. The Sun-as-an-X-ray-star (SaXS) approach uses the Sun as a spatially resolved template to interpret stellar spectra, but previous SaXS ...
Joseph W. M., Stelzer B., Orlando S., Klawin M.   +3 more
doaj   +1 more source

Syn‐ to Post‐Collisional Tectonic History of the Paleo‐Tethyan Orogenic Belt: Insights From Triassic Igneous Rocks in the North–Central Tibetan Plateau, China

Geochemistry, Geophysics, Geosystems, Volume 27, Issue 6, June 2026.
Abstract The closure of the Paleo‐Tethys Ocean was one of the most important global geological events which formed the framework of the East Asian continent during the early Mesozoic. The Longmu Co‐Shuanghu suture zone is considered to record closure of the main basin of the Paleo‐Tethys Ocean.
Jinyong Li, Qingguo Zhai, Yiming Liu, Peiyuan Hu, Yue Tang, Lingfang Wu, Ning Yang   +6 more
wiley   +1 more source

Apache Point Observatory (APO)/SMARTS Flare Star Campaign Observations. I. Blue Wing Asymmetries in Chromospheric Lines during Mid-M-Dwarf Flares from Simultaneous Spectroscopic and Photometric Observation Data

The Astrophysical Journal
We conducted the time-resolved simultaneous optical spectroscopic and photometric observations of mid-M-dwarf flare stars YZ CMi, EV Lac, and AD Leo. Spectroscopic observations were obtained using Apache Point Observatory 3.5 m and Small and Moderate ...
Yuta Notsu, Adam F. Kowalski, Hiroyuki Maehara, Kosuke Namekata, Kenji Hamaguchi, Teruaki Enoto, Isaiah I. Tristan, Suzanne L. Hawley, James R. A. Davenport, Satoshi Honda, Kai Ikuta, Shun Inoue, Keiichi Namizaki, Daisaku Nogami, Kazunari Shibata   +14 more
doaj   +1 more source

The complex phenomena of YSOs revealed by their X-ray variability

, 2019
X-ray observations of Young Stellar Objects (YSOs) have shown several complex phenomena at work.In recent years a few X-ray programs based on long, continuous and, sporadically, simultaneous coordinated multi-wavelengths observations have paved the way ...
Flaccomio, Ettore, Pillitteri, Ignazio, Reale, Fabio, Sciortino, Salvatore   +3 more
core   +1 more source

Jupiter's Auroral Ionosphere: Hybrid Monte Carlo, Auroral Spectrum and Conductivity Modeling

Journal of Geophysical Research: Space Physics, Volume 131, Issue 6, June 2026.
Abstract We present a new model of auroral precipitation and associated phenomena at Jupiter, called the Jupiter Auroral Ionosphere Code (JAIC). The hybrid model follows the primary electron population using a Monte Carlo code that runs on a GPU, and computes the contribution of the secondaries using a two‐stream approximation.
J. D. Nichols
wiley   +1 more source

Multiwavelength Campaign Observations of a Young Solar-type Star, EK Draconis. II. Understanding Prominence Eruption through Data-driven Modeling and Observed Magnetic Environment

The Astrophysical Journal
EK Draconis, a nearby young solar-type star (G1.5V, 50–120 Myr), is known as one of the best proxies for inferring the environmental conditions of the young Sun.
Kosuke Namekata, Kai Ikuta, Pascal Petit, Vladimir S. Airapetian, Aline A. Vidotto, Petr Heinzel, Jiří Wollmann, Hiroyuki Maehara, Yuta Notsu, Shun Inoue, Stephen Marsden, Julien Morin, Sandra V. Jeffers, Coralie Neiner, Rishi R. Paudel, Antoaneta A. Avramova-Boncheva, Keith Gendreau, Kazunari Shibata   +17 more
doaj   +1 more source

Close stars and an inactive accretion disk in Sgr A*: Eclipses and flares

, 2003
A cold neutral and extremely dim accretion disk may be present as a remnant of a past vigorous activity around the black hole in our Galactic Center (GC).
., Nayakshin, Sergei, Sunyaev, Rashid
core   +1 more source