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The methane-nitrogen phase diagram of Prokhvatilov and Yantsevich (1983) indicates that at temperatures relevant to the surfaces of icy dwarf planets like Pluto, two phases contribute to the methane absorptions: nitrogen saturated with…

Earth and Planetary Astrophysics · Physics 2015-06-24 S. Protopapa , W. M. Grundy , S. C. Tegler , J. M. Bergonio

There is observational evidence that central compact objects (CCOs) in supernova remnants have moderately strong magnetic fields $B\sim10^{11}$ G. Meanwhile, available models of partially ionized hydrogen atmospheres of neutron stars with…

High Energy Astrophysical Phenomena · Physics 2014-12-03 A. Y. Potekhin , G. Chabrier , W. C. G. Ho

Jovian Trojan D-type asteroids have mid-infrared emissivity features strikingly similar to comet comae, suggesting that they have the same compositions and that the surfaces of the Trojans are highly porous. However, a direct comparison…

Earth and Planetary Astrophysics · Physics 2016-11-30 Michael S. P. Kelley , Charles E. Woodward , Robert D. Gehrz , William T. Reach , David E. Harker

We construct partially ionized hydrogen atmosphere models for magnetized neutron stars in radiative equilibrium with fixed surface fields between B=10^12 and 2x10^13 G and effective temperatures logT_eff=5.5-6.8, as well as with surface B…

Astrophysics · Physics 2009-06-23 Wynn C. G. Ho , Alexander Y. Potekhin , Gilles Chabrier

Observed X-ray spectra of some isolated magnetized neutron stars display absorption features, sometimes interpreted as ion cyclotron lines. Modeling the observed spectra is necessary to check this hypothesis and to evaluate neutron star…

Solar and Stellar Astrophysics · Physics 2009-07-03 V. F. Suleimanov , A. Y. Potekhin , K. Werner

Observational breakthroughs in the exoplanet field of the last decade motivated the development of numerous theoretical models describing atmospheres and mass loss, which is believed to be one of the main drivers of planetary evolution. We…

Earth and Planetary Astrophysics · Physics 2023-12-13 Daria Kubyshkina , Luca Fossati , Nikolai V. Erkaev

Some thermonuclear (type I) X-ray bursts at the neutron star surfaces in low-mass X-ray binaries take place during hard persistent states of the systems. Spectral evolution of these bursts is well described by the atmosphere model of a…

High Energy Astrophysical Phenomena · Physics 2018-12-17 V. F. Suleimanov , J. Poutanen , K. Werner

(Abridged) Using the Arecibo Observatory we have obtained neutral hydrogen (HI) absorption and emission spectral pairs in the direction of 26 background radio continuum sources in the vicinity of the Perseus molecular cloud. Strong…

Astrophysics of Galaxies · Physics 2015-06-22 Snezana Stanimirovic , Claire E. Murray , Min-Young Lee , Carl Heiles , Jesse Miller

The North Polar Spur (NPS) is a prominent diffuse X-ray feature whose origin has remained uncertain for decades. Using a uniform analysis of archival \textit{Suzaku} and \textit{XMM--Newton} data with new \textit{Chandra} observations, we…

High Energy Astrophysical Phenomena · Physics 2026-05-21 Anjali Gupta , Smita Mathur , Joshua Kingsbury , Anthony Taylor , Sanskriti Das , Joy Bhattacharya , Manami Roy , Yair Krongold

In its decade of operation the Cassini mission has allowed us to look deep into Saturn's atmosphere and investigate the processes occurring below its enshrouding haze. We use Visual and Infrared Mapping Spectrometer (VIMS) 4.6-5.2 micron…

Earth and Planetary Astrophysics · Physics 2016-02-16 Joanna K Barstow , Patrick G. J. Irwin , Leigh N. Fletcher , Rohini S. Giles , Cecile Merlet

Predictions for the acoustic attenuation coefficient and phase speed as functions of frequency and altitude in Saturn's atmosphere are presented and discussed. The pressure range considered in the study is 1 mbar to 1 bar, in windless and…

Earth and Planetary Astrophysics · Physics 2025-07-15 Andrew Powell , Andi Petculescu , Rishbash Chaudhary , Robert White , Don Banfield , Ian Neeson

We construct partially ionized hydrogen atmosphere models for magnetized neutron stars in radiative equilibrium with surface fields B=10^12-5 \times 10^14 G and effective temperatures T_eff \sim a few \times 10^5-10^6 K. These models are…

Astrophysics · Physics 2009-11-10 Wynn C. G. Ho , Dong Lai , Alexander Y. Potekhin , Gilles Chabrier

Cometary studies suggest that the organic composition of the early Solar Nebula was rich in complex nitrile species such a CH$_3$CN. Recent ALMA detections in protoplanetary disks suggest that these species may be common during planet and…

Earth and Planetary Astrophysics · Physics 2018-06-13 Ryan A. Loomis , L. Ilsedore Cleeves , Karin I. Öberg , Yuri Aikawa , Jennifer Bergner , Kenji Furuya , V. V. Guzman , Catherine Walsh

We present an analysis of recent high spatial and spectral resolution ground-based infrared observations of H3+ spectra obtained with the 10-metre Keck II telescope in April 2011. We observed H3+ emission from Saturn's northern and southern…

The Neutron-star Interior Composition ExploreR (NICER) is collecting data to measure the radii of neutron stars by observing the pulsed emission from their surfaces. The primary targets are isolated, rotation-powered pulsars, in which the…

High Energy Astrophysical Phenomena · Physics 2019-02-27 Michi Baubock , Dimitrios Psaltis , Feryal Ozel

The nearby extrasolar planet GJ 436b--which has been labelled as a 'hot Neptune'--reveals itself by the dimming of light as it crosses in front of and behind its parent star as seen from Earth. Respectively known as the primary transit and…

We derive Galactic continuum spectra from 5-96/cm from COBE/FIRAS observations. The spectra are dominated by warm dust emission, which may be fit with a single temperature in the range 16-21 K (for nu^2 emissivity) along each line of sight.…

We present a new computer code for modeling magnetized neutron star atmospheres in a wide range of magnetic fields (10^{12} - 10^{15} G) and effective temperatures (3 \times 10^5 - 10^7 K). The atmosphere is assumed to consist either of…

High Energy Astrophysical Phenomena · Physics 2010-11-23 V. Suleimanov , A. Y. Potekhin , K. Werner

Temperate exoplanets between the sizes of Earth and Neptune, known as "sub-Neptunes", have emerged as intriguing targets for astrobiology. It is unknown whether these planets resemble Earth-like terrestrial worlds with a habitable surface,…

In recent years, JWST has facilitated detections of carbon-bearing molecules in the atmospheres of temperate sub-Neptunes orbiting M dwarfs, ushering in a new era in the characterization of this intriguing planetary regime. We report the…

Earth and Planetary Astrophysics · Physics 2025-12-19 Frances E. Rigby , Nikku Madhusudhan , Subhajit Sarkar , Lorenzo Pica-Ciamarra , Måns Holmberg , Julianne I. Moses