相关论文: Sequestration of noble gases by H3+ in protoplanet…

Type I planetary nebulae (PNe) have high He/H and N/O ratios and are thought to be descendants of stars with initial masses of ~3-8Msun. These characteristics indicate that the progenitor stars experienced proton-capture nucleosynthesis at…

We develop a flexible one-dimensional code to model the escape of hydrogen and helium from a hot Jupiter as a result of photoionization from extreme-ultraviolet (EUV) radiation. We include stellar spectrum heating and ionization, radiative…

The molecular ion H$_3^+$ is a potentially powerful tracer of the ionospheres and thermal structures of Jovian planets, but has never been detected in a planetary mass object outside of the solar system. Models predict that H$_3^+$ emission…

H1821+643 is the most X-ray luminous non-beamed AGN of $L_\mathrm{14-150 keV}= 5.2\times 10^{45}$ erg s$^{-1}$ in the Swift/BAT ultra-hard X-ray survey and it is also a hyper-luminous infrared (IR) galaxy $L_\mathrm{IR} = 10^{13.2} L_\odot$…

The cubic antifluorite structure comprises a face-centered cubic sublattice of anions with cations on the tetrahedral sites. The voids in the antifluorite structure that are crucial for superionicity in Li2O might also act as atomic traps.…

N-bearing molecules (like N2H+ or NH3) are excellent tracers of high-density, low-temperature regions like dense cloud cores and could shed light into snowlines in protoplanetary disks and the chemical evolution of comets. However,…

Emission from the molecular ion H$_3^+$ is a powerful diagnostic of the upper atmosphere of Jupiter, Saturn, and Uranus, but it remains undetected at Neptune. In search of this emission, we present near-infrared spectral observations of…

We compute grids of radiative-convective model atmospheres for Jupiter, Saturn, Uranus, and Neptune over a range of intrinsic fluxes and surface gravities. The atmosphere grids serve as an upper boundary condition for models of the thermal…

Sedimentation rates of silicate grains in gas giant protoplanets formed by disk instability are calculated for protoplanetary masses between 1 M_Saturn to 10 M_Jupiter. Giant protoplanets with masses of 5 M_Jupiter or larger are found to be…

Chemical compositions of planets reveal much about their formation environments. Such information is well sought-after in studies of Solar System bodies and extra-solar ones. Here, we investigate the composition of planetesimals in the beta…

The bolometric radiation from a central body is potentially a powerful driver of atmospheric escape from planets or satellites. When heated above their equilibrium temperatures those satellites, due to their low surface gravity, are be…

High-resolution mass spectra of helium droplets doped with gold and ionized by electrons reveal He$_n$Au$^+$ cluster ions. Additional doping with heavy noble gases results in NenAu+, Ar$_n$Au$^+$, Kr$_n$Au$^+$, and Xe$_n$Au$^+$ cluster…

The Ice Giants Uranus and Neptune have hydrogen-based atmospheres with several constituents that condense in their cold upper atmospheres. A small number of bright cloud systems observed in both planets are good candidates for moist…

Noble gas molecules have not hitherto been detected in space. From spectra obtained with the Herschel Space Observatory, we report the detection of emission in the 617.5 GHz and 1234.6 GHz J = 1-0 and 2-1 rotational lines of {36}ArH^+ at…

Super-Earths and sub-Neptunes are the most common exoplanets, with a "radius valley" suggesting that super-Earths may form by shedding sub-Neptunes' gaseous envelopes. Exoplanets that lie closer to the super-Earth side of the valley are…

Recent observations found close-in planets with significant atmospheres of hydrogen and helium in great abundance. These are the so-called super-Earths and mini-Neptunes. Their atmospheric composition suggests that they formed early during…

We report on the magnetic and Mossbauer properties of polycrystalline HoFe1-xCrxO3 compounds. Magnetization data reveals the continuous tailoring of magnetic transition due to weakening of Ho3+ Fe3+ and Fe3+ Fe3+ interactions in the entire…

Organic material found in meteorites and interplanetary dust particles is enriched in D and 15N. This is consistent with the idea that the functional groups carrying these isotopic anomalies, nitriles and amines, were formed by ion-molecule…

In the Solar System giant planets come in two flavours: 'gas giants' (Jupiter and Saturn) with massive gas envelopes and 'ice giants' (Uranus and Neptune) with much thinner envelopes around their cores. It is poorly understood how these two…

This paper presents an analysis of the concentration of the hydrogen molecule inside the ionized region of planetary nebulae. The equations corresponding to the ionization and chemical equilibria of H, H+, H-, H2, H2+, and H3+ are coupled…