Search Publications
A Surrogate Model for Studying Solar Energetic Particle Transport and the Seed Population
Schwadron, Nathan A.; Baydin, Atilim Guneş; Poduval, Bala
The high energy particles originating from the Sun, known as solar energetic particles (SEPs), contribute significantly to the space radiation environment, posing serious threats to astronauts and scientific instruments on board spacecraft. The mechanism that accelerates the SEPs to the observed energy ranges, their transport in the inner heliosph…
Markov Chain Monte Carlo Optimization applied to Dysonís Visual Double Stars
Budding, E.; Banks, T.; Si, I. S. X. +1 more
Estimates of orbital parameters were made using a Bayesian optimization technique on astrometric data for 25 visual binary systems catalogued a century ago by the ninth Astronomer Royal, Sir Frank Dyson. An advantage of this method is that it provides reliable, unbiased uncertainty estimates for the optimized parameters. Reasonable agreement is fo…
The second Venus flyby of BepiColombo mission reveals stable atmosphere over decades
Haus, Rainer; Arnold, Gabriele; Hiesinger, Harald +4 more
Studies of the Venusian mesosphere provide important information about the current state of the entire Venusian atmosphere. This includes information about the dense cloud structure, its vertical thermal profile, temperature fields, and the resulting dynamical and meteorological processes that contribute to a deeper understanding of the climatolog…
A new approach to retrieve total electron content based on dual-band echoes of MARSIS radar sounder
Wang, Longxiang; Ye, Hongxia
This paper proposes a new dual-band difference (DBD) method to retrieve total electron content (TEC) in Martian ionosphere with the dual-band echoes of the Mars Advanced Radar for Subsurface and Ionosphere Sounding (MARSIS). It establishes the relationship between the group delay difference of two-band echoes and the plasmas frequency. Then the Ma…
An improved spectral extraction method for JWST/NIRSpec fixed slit observations
Thiébaut, E.; Langlois, M.; Ferruit, P. +4 more
The James Webb Space Telescope is performing beyond our expectations. Its Near Infrared Spectrograph (NIRSpec) provides versatile spectroscopic capabilities in the 0.6-5.3 µm wavelength range, where a new window is opening for studying Trans-Neptunian objects in particular. We propose a spectral extraction method for NIRSpec fixed slit observation…
Investigating star-formation activity in Sh 2-61 H II region
Pandey, Rakesh; Sharma, Saurabh; Dewangan, Lokesh +4 more
Using multi-wavelength data sets, we studied the star-formation activity in H II region Sh 2-61 (hereafter S61). We identified a clustering in the region and estimated the membership using the Gaia proper motion data. The physical environment of S61 is inspected using infrared to radio wavelength images. We also determined the Lyman continuum flux…
The Near Infrared and Optical Photometric Activity of V517 Cyg
Larionov, V. M.; Arkharov, A. A.; Klimanov, S. A. +5 more
A near infrared and optical photometric study of Herbig star V517 Cyg has been carried out. The infrared data were obtained in 2003-2017 at the Campo Imperatore Observatory (Italy) with the Pulkovo AZT-24 telescope in the Johnson JHK bands. The optical light curves in the Johnson UBVR bands were obtained at the Maidanak observatory. Additional opt…
Diving deep into the milky way using anti-reflection coatings for astronomical CCDs
Seabroke, George M.; Aggarwal, Anmol; Mittal, Ashi +1 more
We report two anti-reflection (AR) coatings that give better quantum efficiency (QE) than the existing AR coating on the Gaia astrometric field (AF) charged coupled devices (CCDs). Light being the core of optical astronomy is extremely important for such missions, therefore, the QE of the devices that are used to capture it should be substantially…
Effects of stealth CME to ion energisation at ionospheric altitudes of Mars
Thampi, Smitha V.; Venkataraman, V.
The declining phase of Solar cycle 24 produced a slow coronal mass ejection (CME), which was categorized as stealth CME based on the absence of associated low coronal signatures. This CME impacted Mars and caused a major space weather event during 27-28 August 2018 (max vsw = 580 km s-1 near 1.5 AU). The impact of the stealth…
Comprehensive Analysis of a Symbiotic Candidate V503 Her
Boussin, Christophe; Buil, Christian; Medulka, Tomáš +10 more
V503 Her was previously proposed as an eclipsing symbiotic candidate based on photometric behavior and spectroscopic appearance indicating the composite optical spectrum. To investigate its nature, we analyzed long-term photometric observations covering 100 yr of its photometric history and new low-resolution optical spectroscopic data, supplement…