Search Publications
Prediction of intensity of moderate and intense geomagnetic storms using artificial neural network during two complete solar cycles 23 and 24
Singh, Pratyush Kumar
Forward and back: kinematics of the Palomar 5 tidal tails
Bernard, E. J.; Tolstoy, E.; Ferguson, A. M. N. +5 more
The tidal tails of Palomar 5 (Pal 5) have been the focus of many spectroscopic studies in an attempt to identify individual stars lying along the stream and characterize their kinematics. The well-studied trailing tail has been explored out to a distance of 15○ from the cluster centre, while less than 4° have been examined along the lea…
eROSITA X-ray scan of the η Chamaeleontis cluster. Member study and search for dispersed low-mass stars
Schmitt, J. H. M. M.; Czesla, S.; Robrade, J. +2 more
Context. The nearby young open cluster η Chamaeleontis has been observed by eROSITA/SRG during its CalPV phase for 150 ks. The extended ROentgen Survey with an Imaging Telescope Array (eROSITA) data were taken in the field-scan mode, an observing mode of Spectrum-Roentgen-Gamma (SRG) that follows a rectangular grid-like pattern, here covering a 5 …
Spitzer and Herschel studies of dust in supernova remnants in the Small Magellanic Cloud
Filipović, M. D.; Matsuura, Mikako; Barlow, M. J. +6 more
With the entire Small Magellanic Cloud (SMC) mapped by the Spitzer Space Telescope and Herschel Space Observatory, we were able to search 8-250 $\mu$m images in order to identify infrared (IR) emission associated with SMC supernova remnants (SNRs). A valid detection had to correspond with known X-ray, H α, and radio emission from the SNRs. From th…
Using old and new approaches: determining physical properties of brown dwarfs with empirical relations and machine learning models
Best, William M. J.; Feeser, S. Jean
We investigate applications of machine learning models to directly infer physical properties of brown dwarfs from their photometry and spectra using THE CANNON. We demonstrate that absolute magnitudes, spectral types, and spectral indices can be determined from low-resolution SpeX prism spectra of L and T dwarfs without trigonometric parallax meas…
Wide binary stars with non-coeval components
Malkov, Oleg; Kniazev, Alexey
We have the estimated masses of components of visual binaries from their spectral classification. We have selected pairs in which the less massive component looks more evolved. Spectral observations of some of these pairs were made, and at least one pair, HD 156331, was confirmed to have components of different ages. Since mass exchange is exclude…
LatHyS global hybrid simulation of the BepiColombo second Venus flyby
André, N.; Fedorov, A.; Sauvaud, J. -A. +23 more
Plasma and magnetic field observations by BepiColombo during its 2nd Venus flyby in August 10, 2021 have been examined and compared with the newly developed global hybrid simulation LatHyS for the Venusian environment. The LatHyS-Venus simulation was first validated by a comparison with Venus Express observations obtained during average solar wind…
Multipoint Analysis of the Interaction between a Shock and an ICME-like Structure around 2011 March 22
Wang, Yuming; Shen, Chenglong; Xu, Mengjiao +3 more
This work reports on the interaction between a fast forward shock and an interplanetary coronal-mass-ejection-like structure (ICMELS) as observed by in situ observations of radially aligned spacecraft. Around 2011 March 22, the Venus EXpress (VEX) and Solar TErrestrial RElations Observatory-A (STEREO-A) were nearly at the same longitude, providing…
Spectroscopic Line Modeling of the Fastest Rotating O-type Stars
Gies, Douglas R.; Shepard, Katherine; Kaper, Lex +1 more
We present a spectroscopic analysis of the most rapidly rotating stars currently known, VFTS 102 ( ${v}_{e}\sin i=649\pm 52$ km s-1; O9: Vnnne+) and VFTS 285 ( ${v}_{e}\sin i=610\pm 41$ km s-1; O7.5: Vnnn), both members of the 30 Dor complex in the Large Magellanic Cloud. This study is based on high-resolution ultraviolet spe…
Unveiling wide-orbit companions to K-type stars in Sco-Cen with Gaia EDR3
Henning, Thomas; Brown, Anthony G. A.; Ginski, Christian +12 more
Context. The detection of low-mass companions to stellar hosts is important for testing the formation scenarios of these systems. Companions at wide separations are particularly intriguing objects as they are easily accessible for variability studies of the rotational dynamics and cloud coverage of these brown dwarfs or planetary-mass objects.