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Near- and Mid-ultraviolet Observations of X-6.3 Flare on 2024 February 22 Recorded by the Solar Ultraviolet Imaging Telescope on board Aditya-L1
Solanki, Sami K.; Tripathi, Durgesh; Nandy, Dibyendu +10 more
Solar flares are regularly observed in extreme-ultraviolet soft X-rays (SXRs) and hard X-rays (HXRs). However, those in near- and mid-ultraviolet are sparse. The Solar Ultraviolet Imaging Telescope (SUIT) on board the Aditya-L1, launched on 2023 September 2, provides regular observations in the 200–400 nm wavelength range through 11 filters. Here,…
First unambiguous detection of ammonia in the atmosphere of a planetary mass companion with JWST/MIRI coronagraphs
Henning, Thomas; Güdel, Manuel; Boccaletti, Anthony +28 more
Context. The newly accessible mid-infrared (MIR) window offered by the James Webb Space Telescope (JWST) for exoplanet imaging is expected to provide valuable information to characterize their atmospheres. In particular, coronagraphs on board the JWST Mid-InfraRed instrument (MIRI) are capable of imaging the coldest directly imaged giant planets a…
Stellar X-Ray Variability and Planetary Evolution in the DS Tucanae System
Ramsay, Gavin; Wheatley, Peter J.; Bourrier, Vincent +5 more
We present an analysis of four Chandra observations of the 45 Myr old DS Tuc binary system. We observed X-ray variability of both stars on timescales from hours to months, including two strong X-ray flares from star A. The implied flaring rates are in agreement with past observations made with XMM-Newton, though these rates remain imprecise due to…
Disentangling the stellar atmosphere and the focused wind in different accretion states of Cygnus X-1
Russell, D. M.; Svoboda, J.; Skarka, M. +8 more
Context. In high-mass X-ray binaries (HMXBs), the compact object accretes the strong stellar wind of an O-B supergiant companion star. X-ray flux variations alter the stellar wind's ionization state and optical line profiles, which are important in the determination of the orbital parameters of the system. Aims. We analyzed the state-dependent var…
Signatures of simulated spiral arms on radial actions
Recio-Blanco, A.; McMillan, P. J.; Palicio, P. A. +7 more
Context. Spiral arms play a key role in the evolution of disc galaxies, defining their morphology, star formation, chemistry, and dynamics. Among their various implications, it has been observed in the Milky Way disc that the distribution of Gaia Data Release 3 (DR3) radial actions exhibits structures that might be related to the spiral arms. Aims…
JOYS: The [D/H] abundance derived from protostellar outflows across the Galactic disk measured with JWST
Henning, T.; Güdel, M.; Ray, T. P. +11 more
Context. The total deuterium abundance [D/H] in the universe is set by just two processes: the creation of deuterium in Big Bang nucleosynthesis at an abundance of [D/H] = 2.58 ± 0.13 × 10‑5, and its destruction within stellar interiors (astration). Measurements of variations in the total [D/H] abundance can thus potentially provide a p…
Resolving Pleiades Binary Stars with Gaia and Speckle Interferometric Observations
Chulkov, Dmitry; Strakhov, Ivan; Safonov, Boris
The Pleiades is the most prominent open star cluster visible from Earth and an important benchmark for simple stellar populations unified by common origin, age, and distance. Binary stars are its essential ingredient, yet their contribution remains uncertain due to heavy observational biases. A resolved multiplicity survey was conducted for a magn…
Ca II K Polar Network Index of the Sun: A Proxy for Historical Polar Magnetic Field
Chatzistergos, Theodosios; Ermolli, Ilaria; Banerjee, Dipankar +4 more
The Sun's polar magnetic field is pivotal in understanding solar dynamo processes and forecasting future solar cycles. However, direct measurements of the polar field have only been available since the 1970s. The chromospheric Ca II K polar network index (PNI; the fractional area of the chromospheric network regions above a certain latitude) has r…
Connecting Dust and Outflows in Active Galactic Nuclei: The Intriguing Case of NGC 6860
Costantini, E.; Mehdipour, M.; Rogantini, D. +4 more
Cosmic dust plays a crucial role in the evolution of galaxies, significantly influencing star formation and the interstellar medium. However, in active galactic nuclei (AGNs), the role and origin of dust remain poorly understood. High-resolution X-ray spectroscopy is a powerful tool for probing the properties of dust in AGN. NGC 6860, an X-ray bri…
An X-Ray View of the Cataclysmic Variable V902 Mon: Discovery of an X-Ray Eclipse
Mukai, Koji; Islam, Nazma
V902 Mon is one of a few eclipsing intermediate polars (IPs) and shows deep eclipses in the optical lightcurves. The presence of a strong Fe Kα fluorescence line in its X-ray spectrum and its low X-ray flux compared to other IPs suggests significant absorption, most likely from an accretion disk. In an observation carried out using the Nuclear Spe…