Search Publications
Effect of metallicity on the detectability of rotational periods in solar-like stars
Solanki, S. K.; Shapiro, A. I.; Krivova, N. A. +2 more
The accurate determination of stellar rotation periods is important for estimating stellar ages and for understanding stellar activity and evolution. While rotation periods can be determined for about thirty thousand stars in the Kepler field, there are over one hundred thousand stars, especially with low photometric variability and irregular patt…
Binary Fraction Estimation of Main-sequence Stars in 12 Open Clusters: Based on the Homogeneous Data of LAMOST Survey and Gaia DR2
Wang, Jiaxin; Fu, Jianning; Niu, Hubiao
Based on the homogeneous low-resolution spectra data observed by Large Sky Area Multi-Object Fiber Spectroscopic Telescope (LAMOST) and the Gaia Data Release 2 (Gaia DR2) photometric data, we chose 12 open clusters (OCs) to study their fundamental parameters and binary fractions (BFs). For each OC, more than 20 cluster members were observed by LAM…
Evolution of Coronal Mass Ejections and the Corresponding Forbush Decreases: Modeling vs. Multi-Spacecraft Observations
Dumbović, Mateja; Temmer, Manuela; Veronig, Astrid +9 more
One of the very common in situ signatures of interplanetary coronal mass ejections (ICMEs), as well as other interplanetary transients, are Forbush decreases (FDs), i.e. short-term reductions in the galactic cosmic ray (GCR) flux. A two-step FD is often regarded as a textbook example, which presumably owes its specific morphology to the fact that …
The disintegrating old open cluster Czernik 3
Pandey, S. B.; Ojha, D. K.; Ghosh, S. K. +6 more
We have performed a detailed analysis of the Czernik 3 (Cz3) open cluster by using deep near-infrared photometry taken with TIRCAM2 on the 3.6 m Devasthal optical telescope along with the recently available high-quality proper motion data from the Gaia DR2 and deep photometric data from Pan-STARRS1. The cluster has a highly elongated morphology wi…
Know thy star, know thy planet: chemo-kinematically characterizing TESS targets
Vanderburg, Andrew; Hawkins, Keith; Bowler, Brendan P. +2 more
The Transiting Exoplanet Survey Satellite (TESS) has already begun to discover what will ultimately be thousands of exoplanets around nearby cool bright stars. These potential host stars must be well understood to accurately characterize exoplanets at the individual and population levels. We present a catalogue of the chemo-kinematic properties of…
A pulsating white dwarf in an eclipsing binary
Hermes, J. J.; Parsons, Steven G.; Breedt, Elmé +8 more
White dwarfs are the burnt-out cores of Sun-like stars and are the fate of 97 per cent of the stars in our Galaxy. The internal structure and composition of white dwarfs are hidden by their high gravities, which causes all elements apart from the lightest ones to settle out of their atmospheres. The most direct method of probing the inner structur…
Similarities and Differences of Global Dust Storms in MY 25, 28, and 34
Grassi, D.; Giuranna, M.; Amoroso, M. +2 more
To better understand the dust cycle on Mars during years with planet-encircling dust storms, we analyze the last three events that took place in Mars Year (MY) 25, MY 28, and MY 34. Global dust storms that occurred in MY 25 and MY 34 (June 2018) were taking place during equinox, while the MY 28 storm had an onset after perihelion. Before the expan…
Multi-timescale reverberation mapping of Mrk 335
Ingram, Adam; Mastroserio, Guglielmo; van der Klis, Michiel
Time lags due to X-ray reverberation have been detected in several Seyfert galaxies. The different traveltime between reflected and directly observed rays naturally causes this type of lag, which depends directly on the light-crossing time-scale of the system and hence scales with the mass of the central black hole. Featureless 'hard lags' not ass…
Compressed magnetized shells of atomic gas and the formation of the Corona Australis molecular cloud
André, Ph.; Arzoumanian, D.; Palmeirim, P. +4 more
We present the identification of the previously unnoticed physical association between the Corona Australis molecular cloud (CrA), traced by interstellar dust emission, and two shell-like structures observed with line emission of atomic hydrogen (HI) at 21 cm. Although the existence of the two shells had already been reported in the literature, th…
The K2 Galactic Archaeology Program Data Release 2: Asteroseismic Results from Campaigns 4, 6, and 7
Chaplin, William J.; Davies, Guy R.; Huber, Daniel +18 more
Studies of Galactic structure and evolution have benefited enormously from Gaia kinematic information, though additional, intrinsic stellar parameters like age are required to best constrain Galactic models. Asteroseismology is the most precise method of providing such information for field star populations en masse, but existing samples for the m…