Search Publications
Gravity Waves in Titan's Atmosphere: A Comparison Between Linearized Wave Model Calculations and HASI Observations
Cui, Jun; Huang, Jianping; Hao, Yongqiang +3 more
The Huygens Atmospheric Structure Instrument (HASI) detected wavelike temperature fluctuations from 500 to 1,000 km on Titan. However, these fluctuation structures have not been satisfactorily reproduced by any theoretical model to date. In this study, we construct a full-wave model to simulate the observed gravity wave structure. The model includ…
Observation of a Flare and Filament Eruption in Lyman-α on 8 September 2011 by the PRoject for OnBoard Autonomy/Large Yield Radiometer (PROBA2/LYRA)
Kretzschmar, M.; Dammasch, I. E.; Dominique, M. +3 more
The Large Yield Radiometer (LYRA) instrument onboard the PRoject for OnBoard Autonomy (PROBA2) observes the solar irradiance in four channels in the UV-EUV. One of these channels is centered around the hydrogen line at 121.6 nm. The solar Lyman-α emission line is an optically thick line mostly formed in the chromosphere. Although it is one of the …
A survey for variable young stars with small telescopes - V. Analysis of TX Ori, V505 Ori, and V510 Ori, the HST ULLYSES targets in the σ Ori cluster
Eislöffel, Jochen; Hambsch, Franz-Josef; Froebrich, Dirk +2 more
Investigations of the formation of young stellar objects (YSOs) and planets require the detailed analysis of individual sources as well as statistical analysis of a larger number of objects. The Hubble UV Legacy Library of Young Stars as Essential Standards (ULLYSES) project provides such a unique opportunity by establishing a UV spectroscopic lib…
Determination of Sodium Abundance Ratio from Low-resolution Stellar Spectra and Its Applications
Koo, Jae-Rim; Beers, Timothy C.; Lee, Young Sun +2 more
We present a method to determine sodium abundance ratios ([Na/Fe]) using the Na I D doublet lines in low-resolution (R ~ 2000) stellar spectra. As stellar Na I D lines are blended with those produced by the interstellar medium, we developed a technique for removing the interstellar Na I D lines using the relationship between extinction, which is p…
Machine learning as a tool to classify extra-terrestrial landslides: A dossier from Valles Marineris, Mars
Rajaneesh, A.; Vishnu, C. L.; Oommen, T. +2 more
Many researchers studied Martian landslides, and most of these studies are in the Valles Marineris (VM). Those studies are mainly morphologic analysis, estimates of landslide deposit volumes, thermal properties of the landslides, spectral analyses, and mapping and classifying landslides. But, this study created a robust landslide inventory of 682 …
The SHARDDS survey: limits on planet occurrence rates based on point sources analysis via the Auto-RSM framework
Marshall, J. P.; del Burgo, C.; Absil, O. +7 more
Context. In the past decade, high contrast imaging allowed the detection and characterisation of exoplanets, brown dwarfs, and circumstellar disks. Large surveys provided new insights about the frequency and properties of massive sub-stellar companions with separations from 5 to 300 au.
Aims: In this context, our study aims to detect and char…
Quasi-stellar objects and galaxy mass density profiles derived using the submillimetre galaxies magnification bias
Bonavera, L.; González-Nuevo, J.; Cueli, M. M. +3 more
Context. The magnification bias on the submillimetre galaxies (SMGs) is a gravitational lensing effect, where the SMGs are used as background lensed galaxies. This effect can be used to investigate the mass density profiles of different types of foreground lenses.
Aims: In this work, we want to exploit the magnification bias of the SMGs using…
A chemical analysis of seven red giants of the Galactic cluster NGC 4349
Pereira, C. B.; Holanda, N.; Ramos, André A. +2 more
In this study, we undertake a comprehensive investigation of seven red giant stars of NGC 4349 (#005, #009, #079, #127, #168, #174, and #203) and one non-member star (#053). Accurate abundances of 19 chemical species and 12C/13C isotopic ratio are determined using high-signal-to-noise FEROS spectra and standard spectroscopic …
Contribution of Spicules to Solar Coronal Emission
Klimchuk, James A.; Sarkar, Aveek; Sow Mondal, Shanwlee
Recent high-resolution imaging and spectroscopic observations have generated renewed interest in spicules' role in explaining the hot corona. Some studies suggest that some spicules, often classified as type II, may provide significant mass and energy to the corona. Here we use numerical simulations to investigate whether such spicules can produce…
Monitoring accretion rate variability in the Orion Nebula Cluster with the Wendelstein Wide Field Imager
Manara, C. F.; Preibisch, T.; Ercolano, B. +2 more
Context. The understanding of the accretion process has a central role in the understanding of star and planet formation.
Aims: We aim to test how accretion variability influences previous correlation analyses of the relation between X-ray activity and accretion rates, which is important for understanding the evolution of circumstellar disks …