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Related papers: The Atomic Hydrogen Cloud in the Saturnian System

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We perform axisymmetric hydrodynamical simulations that describe the nonlinear outcome of the viscous overstability in dense planetary rings. These simulations are particularly relevant for Cassini observations of fine-scale structure in…

Earth and Planetary Astrophysics · Physics 2015-05-19 Henrik N. Latter , Gordon I. Ogilvie

The internal composition of sub-Neptunes remains a prominent unresolved question in exoplanetary science. We present a technique to place constraints on envelope mean molecular weight that utilises observations of escaping hydrogen or…

Earth and Planetary Astrophysics · Physics 2026-01-21 James G. Rogers , James E. Owen , Ethan Schreyer , James Kirk

This study presents a 13 years survey of haze UV extinction profiles, monitoring the temporal evolution of the detached haze layer (DHL) in Titan's upper atmosphere (350-600 km). As reported by West et al. 2011 (GRL vol.38, L06204) at the…

Earth and Planetary Astrophysics · Physics 2021-02-11 Benoît Seignovert , Pascal Rannou , Robert A. West , Sandrine Vinatier

Titan's middle atmosphere is currently experiencing a rapid change of season after northern spring arrived in 2009. A large cloud was observed for the first time above Titan's southern pole in May 2012, at an altitude of 300 km. This…

Earth and Planetary Astrophysics · Physics 2015-06-23 Remco J. de Kok , Nicholas A. Teanby , Luca Maltagliati , Patrick G. J. Irwin , Sandrine Vinatier

Gas in galactic disks is collected by gravitational instabilities into giant atomic-molecular complexes, but only the inner, molecular parts of these structures are able to collapse to form stars. Determining what controls the ratio of…

Astrophysics · Physics 2009-11-13 Mark R. Krumholz , Christopher F. McKee , Jason Tumlinson

Earth and Titan are two planetary bodies formed far from each other. Nevertheless the chemical composition of their atmospheres exhibits common indications of being produced by the accretion, plus ulterior in-situ processing of cometary…

Earth and Planetary Astrophysics · Physics 2015-05-27 Josep M. Trigo-Rodriguez , F. Javier Martin-Torres

Numerous land and space-based observations have established that Saturn has a persistent hexagonal flow pattern near its north pole. While observations abound, the physics behind its formation is still uncertain. Although several…

Fluid Dynamics · Physics 2020-07-20 Rakesh Kumar Yadav , Jeremy Bloxham

Hundreds of high-velocity atomic gas clouds exist above and below the Galactic Centre, with some containing a molecular component. However, the origin of these clouds in the Milky Way's wind is unclear. This paper presents new…

We revisit the evidence for a "dust cloud" observed by the Cassini spacecraft at Saturn in 2006. The simultaneous data of 3 instruments are compared to interpret the signatures of a coherent swarm of dust that could have remained floating…

Earth and Planetary Astrophysics · Physics 2015-05-19 Emil Khalisi

The atomic-to-molecular hydrogen (H/H2) transition has been extensively studied as it controls the fraction of gas in a molecular state in an interstellar cloud. This fraction is linked to star-formation by the Schmidt-Kennicutt law. While…

Astrophysics of Galaxies · Physics 2021-12-08 Vincent Maillard , Emeric Bron , Franck Le Petit

The origin of our Galaxy's high-velocity clouds (HVCs) remains a mystery after many decades of effort. In this paper, we use the TNG50 simulation of the IllustrisTNG project to identify cool, dense clouds that match observations of Galactic…

Astrophysics of Galaxies · Physics 2024-10-21 Scott Lucchini , Jiwon Jesse Han , Lars Hernquist , Charlie Conroy

In this paper we present a study of the vertical haze and cloud structure over a triple vortex in Saturn's atmosphere in the planetographic latitude range 55N-69N (del Rio- Gaztelurrutia et al. , 2018) using HST/WFC3 multispectral imaging.…

Earth and Planetary Astrophysics · Physics 2019-06-04 J. F. Sanz-Requena , S. Perez-Hoyos , A. Sanchez-Lavega , T. del Rio-Gaztelurrutia , P. G. J. Irwin

The Moon-forming giant impact extensively melts and partially vaporizes the silicate Earth and delivers a substantial mass of metal to Earth's core. Subsequent evolution of the magma ocean and overlying atmosphere has been described by…

Earth and Planetary Astrophysics · Physics 2019-10-24 Kaveh Pahlevan , Laura Schaefer , Marc M. Hirschmann

We have discovered 6 10^7 M_{\odot} of atomic gas at a projected distance greater than 4' (20 kpc) from the highly inclined Virgo spiral galaxy NGC 4388. This gas is most probably connected to the very extended H\alpha plume detected by…

Astrophysics · Physics 2009-11-07 B. Vollmer , W. Huchtmeier

Using data from the Southern Galactic Plane Survey (SGPS) we analyze an HI self-absorption cloud centered on l = 318.0 deg, b = -0.5 deg, and velocity, v = -1.1 km/s. The cloud was observed with the Australia Telescope Compact Array (ATCA)…

Astrophysics · Physics 2009-11-10 D. W. Kavars , J. M. Dickey , N. M. McClure-Griffiths , B. M. Gaensler , A. J. Green

The deuterium to hydrogen ratio in water ice in a planetary body carries important information on the history of water processing and delivery in the protostellar nebula. For a giant planet satellite, the D/H ratio is also affected by the…

Earth and Planetary Astrophysics · Physics 2025-10-17 Michael E. Brown , Samantha K. Trumbo , M. Ryleigh Davis , Swaroop Chandra

Most detected neutral atomic hydrogen (HI) at low redshift is associated with optically bright galaxies. However, a handful of HI clouds are known which appear to be optically dark and have no nearby potential progenitor galaxies, making…

Astrophysics of Galaxies · Physics 2018-05-23 Rhys Taylor , Richard Wünsch , Jan Palouš

We investigate the origin and fate of the recently discovered gas cloud G2 close to the Galactic Center. Our hydrodynamical simulations focussing on the dynamical evolution of the cloud in combination with currently available observations…

Astrophysics of Galaxies · Physics 2015-06-04 M. Schartmann , A. Burkert , Ch. Alig , S. Gillessen , R. Genzel , F. Eisenhauer , T. K. Fritz

We present a detailed theoretical analysis of a non-thermal escape of molecular hydrogen from Mars induced by collisions with hot atomic oxygen from martian corona. To accurately describe the energy transfer in O + H$_2(v,j)$ collisions, we…

Earth and Planetary Astrophysics · Physics 2013-11-13 Marko Gacesa , Peng Zhang , Vasili Kharchenko

Titan's 'detached' haze, seen in Voyager images in 1980 and 1981 and monitored by the Cassini Imaging Science Subsystem (ISS), during the period 2004-2017, provides a measure of seasonal activity in Titan's mesosphere with observations over…

Earth and Planetary Astrophysics · Physics 2018-05-01 Robert A. West , Benoît Seignovert , Pascal Rannou , Philip Dumont , Elizabeth P. Turtle , Jason Perry , Mou Roy , Aida Ovanessian