Search Publications
Modeling a Coronal Mass Ejection as a Magnetized Structure with EUHFORIA
Singh, Jagdev; Asvestari, E.; Sindhuja, G. +1 more
We studied an Earth-directed coronal mass ejection (CME) that erupted on 2015 March 15. Our aim was to model the CME flux rope as a magnetized structure using the European Heliospheric Forecasting Information Asset (EUHFORIA). The flux rope from eruption data (FRED) output was applied to the EUHFORIA spheromak CME model. In addition to the geometr…
Millisecond Pulsars in Dense Star Clusters: Evolution, Scaling Relations, and the Galactic-center Gamma-Ray Excess
Ye, Claire S.; Fragione, Giacomo
The number of millisecond pulsars (MSPs) observed in Milky Way globular clusters has increased explosively in recent years, but the underlying population is still uncertain due to observational biases. We use state-of-the-art N-body simulations to study the evolution of MSP populations in dense star clusters. These cluster models span a wide range…
An Updated View of the Milky Way from Maser Astrometry
Immer, Katharina; Rygl, Kazi L. J.
Astrometric observations of maser sources in the Milky Way, using the Very Long Baseline Interferometry (VLBI) technique, have been exploited to determine the spiral structure of our Galaxy. Several major spiral arms have now been pinpointed in the first and second Galactic quadrants. Fundamental Galactic parameters such as the distance to the Gal…
Analysis of four solar occultations by Titan's atmosphere with the infrared channel of the VIMS instrument: Haze, CH4, CH3D, and CO vertical profiles
Rannou, P.; Vinatier, S.; Coutelier, M. +1 more
Titan, the largest satellite of Saturn, has a dense atmosphere mainly composed of nitrogen, methane at a percent level, and minor species. It is also covered by a thick and global photochemical organic haze. In the last two decades, the observations made by the Cassini orbiter and the Huygens probe have greatly improved our knowledge of Titan's sy…
Multiwavelength Mitigation of Stellar Activity in Astrometric Planet Detection
Solanki, Sami K.; Macintosh, Bruce; Krivova, Natalie +4 more
Astrometry has long been a promising technique for exoplanet detection. At the theoretical limits, astrometry would allow for the detection of smaller planets than previously seen by current exoplanet search methods, but stellar activity may make these theoretical limits unreachable. Astrometric jitter of a Sun-like star due to magnetic activity i…
Automated Detection of coronaL MAss Ejecta origiNs for Space Weather AppliCations (ALMANAC)
Morgan, Huw; Williams, Thomas
Alerts of potentially hazardous coronal mass ejection (CME) are based on the detection of rapid changes in remote observations of the solar atmosphere. This paper presents a method that detects and estimates the central coordinates of CME eruptions in Extreme Ultraviolet data, with the dual aim of providing an early alert, and giving an initial es…
An arid-semiarid climate during the Noachian-Hesperian transition in the Huygens region, Mars: Evidence from morphological studies of valley networks
Xiao, Long; Zhao, Jiannan; Yang, Yong +2 more
Fluvial activities play important roles in the geologic evolution of early Mars. As one of the most ancient fluvial features on Mars, the widely distributed valley networks (VNs) provide clues for understanding the early martian climate. Our study focuses on the morphological and hydrological features of VNs around the Huygens basin in the ancient…
Testing the accretion scenario of λ Boo stars
Angeloni, R.; Jaque Arancibia, M.; Veramendi, M. E. +5 more
Context. The existence of a group of λ Boo stars has been known for years, however, the origin of its chemical peculiarity is still a matter of debate.
Aims: Our aim is to test the accretion scenario of λ Boo stars. This model predicts that in a binary system with two early-type stars passing through a diffuse cloud, both stars ought to displ…
Kinematic characteristics of the Milky Way globular clusters based on Gaia DR2 data
Chemerynska, I. V.; Ishchenko, M. V.; Sobolenko, M. O. +2 more
Using the data from Gaia (ESA) Data Release 2 we performed the orbital calculations of globular clusters (GCs) of the Milky Way. To explore possible close encounters (or collisions) between the GCs, using our own developed high-order φ-GRAPE code, we integrated backward and forward orbits of 119 objects with reliable positions and proper motions. …
Hα spectroscopy of the recurrent nova RS Oph during the 2021 outburst
Stoyanov, K. A.; Marchev, D.; Zamanov, R. K. +3 more
We report spectroscopic observations of the Hα emission line of the recurrent nova RS~Oph obtained between 2021 August 12 and 2021 August 23 during the recent outburst. On the basis of the sharp P~Cyg profile superimposed onto the strong Hα emission, we estimate that the outflowing velocity of the material surrounding RS~Oph is in the range 32 km …