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Saturn's auroral/polar H3+ infrared emission: The effect of solar wind compression
Dougherty, Michele K.; Bunce, Emma J.; Melin, Henrik +6 more
Previous investigations into Saturn's aurora have shown that they are strongly controlled by the solar wind. Here, for the first time, we use a combination of ground-based infrared observations of the aurora and in situ measurements of the magnetosphere in order to better understand this association. We show that large-scale variability in both th…
First Observation in the South of Titan's Far-infrared 220 cm-1 Cloud
Teanby, N. A.; Calcutt, S. B.; de Kok, R. +15 more
An emission feature at 220 cm-1 which has been attributed to a cloud of condensed material in Titan's winter stratosphere has been seen for the first time in the south. This feature had previously been found only at high northern latitudes during northern winter and spring. The material emitting at 220 cm-1, as yet unidentifi…
A newly discovered impact crater in Titan's Senkyo: Cassini VIMS observations and comparison with other impact features
Le Mouélic, S.; Sotin, C.; Brown, R. H. +7 more
Senkyo is an equatorial plain on Titan filled with dunes and surrounded by hummocky plateaus. During the Titan targeted flyby T61 on August 25, 2009, the Cassini Visual and Infrared Mapping Spectrometer (VIMS) onboard the Cassini spacecraft observed a circular feature, centered at 5.4° N and 341°W, that superimposes the dune fields and a bright pl…
An alternative origin for debris rings of planetesimals
Nayakshin, Sergei; Cha, Seung-Hoon
Core accretion (CA), the most widely accepted scenario for planet formation, postulates existence of ∼ km-sized solid bodies, called planetesimals, arranged in a razor-thin disc in the earliest phases of planet formation. These objects coagulate by collisions, eventually building planetary cores. In the tidal downsizing (TD) hypothesis, an alterna…
Possible sources for methane and C2-C5 organics in the plume of Enceladus
McKay, C. P.; Khare, B. N.; Amin, R. +2 more
We consider six possible sources of CH4 and other lowmass (C2-C5) organics in the plume of Enceladus: three of these sources represent initial endowments of organics: cometary organics, Titan-like tholin, and the Fisher-Tropsch type reactions in the gases from which Enceladus formed. The other three sources represe…
Investigating the reflection contribution to the X-ray emission of Ton S180
Fabian, A. C.; Nardini, E.; Walton, D. J.
There is now growing evidence that the soft X-ray excess is almost ubiquitous among unobscured active galaxies. In spite of the various interpretations that have been considered in the past few years, the nature of this foremost spectral feature is not firmly established yet. In this context, we review from a reflection perspective the three highe…
A Search for Pulsations in Helium White Dwarfs
Howell, Steve B.; Fulton, Benjamin J.; Marsh, T. R. +5 more
The recent plethora of sky surveys, especially the Sloan Digital Sky Survey, have discovered many low-mass (M < 0.45 M⊙) white dwarfs that should have cores made of nearly pure helium. These WDs come in two varieties: those with masses 0.2 < M < 0.45 M⊙ and H envelopes so thin that they rapidly cool and those with M …
Accurate localization and identification of six hard X-ray sources from Chandra and XMM-Newton data
Lutovinov, A. A.; Revnivtsev, M. G.; Karasev, D. I. +1 more
We present the results of Chandra and XMM-Newton observations for six hard X-ray sources (IGR J12134-6015, IGR J18293-1213, IGR J18219-1347, IGR J17350-2045, IGR J18048-1455, XTE J1901+014) from the INTEGRAL all-sky survey. Based on these observations, we have improved significantly the localization accuracy of the objects and, therefore, have man…
The S4G Perspective on Circumstellar Dust Extinction of Asymptotic Giant Branch Stars in M100
Holwerda, Benne; Ho, Luis C.; Meidt, Sharon E. +19 more
We examine the effect of circumstellar dust extinction on the near-IR (NIR) contribution of asymptotic giant branch (AGB) stars in intermediate-age clusters throughout the disk of M100. For our sample of 17 AGB-dominated clusters we extract optical-to-mid-IR spectral energy distributions (SEDs) and find that NIR brightness is coupled to the mid-IR…
Adhesion and collisional release of particles in dense planetary rings
Schmidt, Jürgen; Spahn, Frank; Bodrova, Anna +1 more
We propose a simple theoretical model for aggregative and fragmentative collisions in Saturn’s dense rings. In this model the ring matter consists of a bimodal size distribution: large (meter sized) boulders and a population of smaller particles (tens of centimeters down to dust). The small particles can adhesively stick to the boulders and can be…