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An imaged 15 MJup companion within a hierarchical quadruple system
Henning, T.; Janson, M.; Langlois, M. +20 more
Context. Since 2019, the direct imaging B-star Exoplanet Abundance STudy (BEAST) at SPHERE@VLT has been scanning the surroundings of young B-type stars in order to ascertain the ultimate frontiers of giant planet formation. Recently, the 17−4+3 Myr HIP 81208 was found to host a close-in (∼50 au) brown dwarf and a wider (∼230 …
A survey for variable young stars with small telescopes: VI - Analysis of the outbursting Be stars NSW 284, gaia 19eyy, and VES 263
De, Kishalay; Hillenbrand, Lynne A.; Eislöffel, Jochen +44 more
This paper is one in a series reporting results from small telescope observations of variable young stars. Here, we study the repeating outbursts of three likely Be stars based on long-term optical, near-infrared, and mid-infrared photometry for all three objects, along with follow-up spectra for two of the three. The sources are characterized as …
Artificial neural network for star tracker centroid computation
Zapevalin, P. R.; Novoselov, A.; Zharov, V. E.
We propose a unique dataset with star images, their centroids, and a new centroid algorithm based on machine learning, that significantly improves star image centroid performance. The centroid of the star image is the subpixel coordinates on the image plane corresponding to the assumed point source of the light (a star). We have compiled and open-…
White-light Superflare and Long-term Activity of the Nearby M7-type Binary EI Cnc Observed with GWAC System
Wang, Jing; Liang, En-Wei; Wang, Xiang-Gao +14 more
Stellar white-light flares are believed to play an essential role in the physical and chemical properties of the atmosphere of the surrounding exoplanets. Here we report an optical monitoring campaign on the nearby flaring system EI Cnc carried out by the Ground-based Wide Angle Camera (GWAC) and its dedicated follow-up telescope. A superflare, co…
Thermal emission from the hot Jupiter WASP-103 b in J and Ks bands
Henning, Thomas; Zhao, Gang; Wang, Wei +9 more
Hot Jupiters, particularly those with temperature higher than 2000 K, are the best sample of planets that allow in-depth characterization of their atmospheres. We present here a thermal emission study of the ultrahot Jupiter WASP-103 b observed in two secondary eclipses with CFHT/WIRCam in J and Ks bands. By means of high precision diff…
Exploring the potential of Twinkle to unveil the nature of LTT 1445 Ab
Gaudi, B. Scott; Wang, Ji; Phillips, Caprice L. +3 more
We explore the prospects for Twinkle to determine the atmospheric composition of the nearby terrestrial-like planet LTT 1445 Ab, including the possibility of detecting the potential biosignature ammonia (NH3). At a distance of 6.9 pc, this system is the second closest known transiting system and will be observed through transmission spe…
Near-infrared evolution of the equatorial ring of SN 1987A
Larsson, J.; Lundqvist, P.; Fransson, C. +4 more
We used adaptive optics imaging and integral field spectroscopy from the Very Large Telescope, together with images from the Hubble Space Telescope, to study the near-infrared (NIR) evolution of the equatorial ring (ER) of SN 1987A. We studied the NIR flux and morphology over time in order to lay the groundwork for James Webb Space Telescope obser…
CO enhancement by magnetohydrodynamic waves. Striations in the Polaris Flare
Panopoulou, G. V.; Goldsmith, P. F.; Pelgrims, V. +4 more
Context. The formation of molecular gas in interstellar clouds is a slow process, but can be enhanced by gas compression. Magneto-hydrodynamic (MHD) waves can create compressed quasi-periodic linear structures, referred to as striations. Striations are observed at the column densities at which the transition from atomic to molecular gas takes plac…
Spins and shapes of basaltic asteroids and the missing mantle problem
Hasegawa, Sunao; Oszkiewicz, Dagmara; Skiff, Brian A. +31 more
Basaltic V-type asteroids are common in the inner part of the Main Asteroid Belt and much less abundant in the mid and outer parts. They are of scientific interest because they sample crusts and mantles of theoretically plentiful differentiated planetesimals that existed in the Solar System four billion years ago. Some Solar System theories sugges…
Unusual Hard X-Ray Flares Caught in NICER Monitoring of the Binary Supermassive Black Hole Candidate AT2019cuk/Tick Tock/SDSS J1430+2303
Fabian, Andrew C.; Remillard, Ronald A.; Arzoumanian, Zaven +17 more
The nuclear transient AT2019cuk/Tick Tock/SDSS J1430+2303 has been suggested to harbor a supermassive black hole (SMBH) binary near coalescence. We report results from high-cadence NICER X-ray monitoring with multiple visits per day from 2022 January to August, as well as continued optical monitoring during the same time period. We find no evidenc…