Search Publications
The Bottom-light Present Day Mass Function of the Peculiar Globular Cluster NGC 6535
Zaritsky, Dennis; Halford, Melissa
Dynamical mass calculations have suggested that the Milky Way globular cluster NGC 6535 belongs to a population of clusters with high mass-to-light ratios, possibly due to a bottom-heavy stellar initial mass function (IMF). We use published Hubble Space Telescope data to measure the present day stellar mass function of this cluster within its half…
Photochemical response to the variation of temperature in the 2011-2012 stratospheric vortex of Saturn
Fletcher, L. N.; Hartogh, P.; Hue, V. +4 more
Context. A hot vortex formed in the stratosphere of Saturn following the 2010-2011 Northern Storm. Huge temperature increases have been measured in the vortex around the millibar level. Enhancements in hydrocarbon abundances have been observed at the millibar level in 2011-2012 inside this vortex.
Aims: We model the time-dependent photochemis…
Degradation assessment of LYRA after 5 years on orbit - Technology Demonstration -
Gissot, S.; Schühle, U.; Saito, T. +10 more
We present a long-term assessment of the radiometric calibration and degradation of the Large Yield Radiometer (LYRA), which has been on orbit since 2009. LYRA is an ultraviolet (UV) solar radiometer and is the first space experiment using aboard a pioneering diamond detector technology. We show that LYRA has degraded after the commissioning phase…
Oxygen emission in remnants of thermonuclear supernovae as a probe for their progenitor system
Kaastra, J. S.; Kosenko, D.; Blinnikov, S. I. +3 more
Recent progress in numerical simulations of thermonuclear supernova explosions brings up a unique opportunity in studying the progenitors of Type Ia supernovae. Coupling state-of-the-art explosion models with detailed hydrodynamical simulations of the supernova remnant evolution and the most up-to-date atomic data for X-ray emission calculations m…
Discovery of suprathermal Fe+ in Saturn's magnetosphere
Krimigis, S. M.; Mitchell, D. G.; Hamilton, D. C. +3 more
Measurements in Saturn's equatorial magnetosphere from mid-2004 through 2013 made by Cassini's charge-energy-mass ion spectrometer indicate the presence of a rare, suprathermal (83-167 keV/e) ion species at Saturn with mass ~56 amu that is likely Fe+. The abundance of Fe+ is only ~10-4 relative to that of W+
Is HE 0436-4717 Anemic? A deep look at a bare Seyfert 1 galaxy
Gallo, L. C.; Vasudevan, R.; Bonson, K.
A multi-epoch, multi-instrument analysis of the Seyfert 1 galaxy HE 0436-4717 is conducted using optical to X-ray data from XMM-Newton and Swift (including the Burst Alert Telescope). Fitting of the UV-to-X-ray spectral energy distribution shows little evidence of extinction and the X-ray spectral analysis does not confirm previous reports of deep…
Reduced Coronal Emission Above Large Isolated Sunspots
Gary, D. E.; Shibasaki, K.; Peterova, N. G. +2 more
We analysed specific regions of reduced soft X-ray and microwave emission in five large isolated sunspots. The Nobeyama Radioheliograph 17 GHz observations reveal a local depression of microwave brightness in the peripheral area of the sunspots. The depression regions appear light (weak absorption) in the He 10830 Å line in areas with extended (op…
Morphometry of volcanic cones on Mars in perspective of Astrobiological Research
Gilichinsky, Michael; Demidov, Nikita; Rivkina, Elizaveta
The permanently frozen volcanic sediment is one of the most promising geological objects for searching life on Mars. On Earth, volcanic intrusions into permafrost result in formation of the unique microbial communities. We propose several terrestrial analogues of Martian polar volcanoes, such as the permanently frozen volcanic sediments on the Kam…
The fundamental parameters of the Ap star 78 Virginis. Could 78 Vir be a rapidly oscillating Ap star?
Meilland, A.; Sturmann, J.; Sturmann, L. +11 more
Context. Determining the effective temperature of Ap stars, including the roAp stellar pulsators, is a difficult task owing to their strong magnetic field and their related spotted surfaces. It is, however, an important step towards constraining models of their complex atmosphere and testing proposed pulsation excitation mechanisms.
Aims: Usi…
Touchdown on Venus: Analytic wind models and a heuristic approach to estimating landing dispersions
Lorenz, Ralph D.
The 'landing ellipse' or region of uncertainty within which an unguided probe to Venus may be expected to land is calculated. The region can be usefully seen as the convolution of three different factors: an initial circular delivery uncertainty which is smeared at a grazing entry angle onto the planetary sphere, an along-track uncertainty due to …