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Hubble Detects the Start of a New Saturn Ring Spoke Season
Nicholson, Philip D.; Hedman, Matthew M.; Showalter, Mark R. +4 more
Saturn's ring spokes typically appear over an 8-year duration centered on equinox. Hubble Space Telescope observations in 2021 indicate the beginning of a new spoke season as Saturn approaches equinox in 2025. The spokes show increased contrast and longevity in 2022, persisting for up to 11 hours. The spokes are visible from UV to near-IR and are …
Modeling the Chromosphere and Transition Region of Planet-hosting Star GJ 436
Peacock, Sarah; Barman, Travis; Hatzes, Artie P. +12 more
Ahead of upcoming space missions intending to conduct observations of low-mass stars in the ultraviolet (UV) spectral region it becomes imperative to simultaneously conduct atmospheric modeling from the UV to the visible (VIS) and near-infrared (NIR). Investigations on extended spectral regions will help to improve the overall understanding of the…
Searching for signatures of H α spicule-like features in the solar transition region
Shetye, Juie; Doyle, J. Gerry; Vilangot Nhalil, Nived
New instruments and telescopes covering the optical and ultraviolet spectral regions have revealed a range of small-scale dynamic features, many which may be related. For example, the range of spicule-like features hints towards a spectrum of features and not just two types; however, direct observational evidence in terms of tracking spicules acro…
Spectroscopic study of Herbig Ae/Be stars in the Galactic anti-centre region from LAMOST DR5
Arun, R.; Mathew, Blesson; Kartha, Sreeja S. +3 more
We study a sample of 119 Herbig Ae/Be stars in the Galactic anti-centre direction using the spectroscopic data from large sky area multi-object fiber spectroscopic telescope survey program. Emission lines of hydrogen belonging to the Balmer and Paschen series, and metallic lines of species such as Fe II, O I, Ca II triplet are identified. A modera…
Testing the planetary hypothesis of NY Virginis: anticipated change in the eclipse timing trend within the next five years
Baştürk, Özgür; Esmer, Ekrem Murat; Selam, Selim Osman
Regarding the recent debate about the potential circumbinary exoplanets around NY Virginis (NY Vir), we analysed mid-eclipse timings of NY Vir using archival photometric data as well as our own observations and the ones from TESS. For this purpose, we first modelled the available eclipse light curves of the binary system to determine the masses of…
LBT-MODS spectroscopy of high-redshift candidates in the Chandra J1030 field. A newly discovered z ∼ 2.8 large-scale structure
Comastri, Andrea; Signorini, Matilde; Vito, Fabio +13 more
We present the results of a spectroscopic campaign with the Multi-Object Double Spectrograph (MODS) instrument mounted on the Large Binocular Telescope (LBT), aimed at obtaining a spectroscopic redshift for seven Chandra J1030 sources with a photometric redshift ≥2.7 and optical magnitude rAB = [24.5 − 26.5]. We obtained a spectroscopic…
Massive Hypervelocity Runaway Stars in the Large Magellanic Cloud
Xu, Ye; Liu, Dejian; Hao, Chaojie +3 more
Since the hypervelocity stars were discovered in the Milky Way, various mechanisms have been proposed to explain these runaway stars. Up to now, however, the dominant ejected mechanism of hypervelocity stars is still unclear. As the largest and closest face-on satellite galaxy of the Milky Way, the Large Magellanic Cloud (LMC) serves as a good tar…
NuSTAR Hard X-Ray Monitoring of Gravitationally Lensed Quasar RX J1131-1231
Zoghbi, Abderahmen; Dai, Xinyu; Morgan, Christopher W. +2 more
The X-ray emission from active galactic nuclei is believed to come from a combination of inverse Compton scattering of photons from the accretion disk and reprocessing of the direct X-ray emission by reflection. We present hard (10-80 keV) and soft (0.5-8 keV) X-ray monitoring of a gravitationally lensed quasar RX J1131-1231 (hereafter RXJ1131) wi…
CHEX-MATE: X-ray absorption and molecular content of the interstellar medium toward galaxy clusters
Pointecouteau, E.; Pratt, G. W.; Rossetti, M. +14 more
The X-ray spectrum of extragalactic sources, such as galaxy clusters, is affected by the photo-absorption of various components of the Galactic interstellar medium (ISM). The resulting spectral distortion contributes to the systematics of cluster temperature measurements. It essentially depends on the neutral (atomic+molecular) Galactic hydrogen d…
A clustering study of the old open cluster Trumpler 19
Gao, Xinhua; Fang, Dan
In this paper, we investigate the spatial structure and dynamical state of the poorly studied old (