Related papers: H\alpha\ Absorption in Transiting Exoplanet Atmosp…
Absorption in the stellar Lyman-$\alpha$ (Ly-$\alpha$) line observed during the transit of the extrasolar planet HD 209458b reveals high velocity atomic hydrogen at great distances from the planet. This has been interpreted as hydrogen…
We study the impact of neutral hydrogen absorption on ${\rm H_2}$ photodissociation in protogalactic haloes exposed to soft-UV radiation. Lyman-series absorption can significantly deplete dissociating photons as line overlap with the ${\rm…
We modeled the transit signatures in the Lya line of a putative Earth-sized planet orbiting in the HZ of the M dwarf GJ436. We estimated the transit depth in the Lya line for an exo-Earth with three types of atmospheres: a…
Despite previous intensive ground-based imaging and spectroscopic campaigns and wide-band HST imaging of the z=0.927 QSO 3C336 field, the galaxy that hosts the damped Ly-alpha system along this line-of-sight has eluded detection. We present…
We investigate the Lyman alpha line transfer in nearby and high redshift starbursting galaxies, where the effect of high optical depths and the role of dust in the scattering medium are expected to be conspicuous and should be treated in a…
GJ 1132b, which orbits an M dwarf, is one of the few known Earth-sized planets, and at 12 pc away it is one of the closest known transiting planets. Receiving roughly 19x Earth's insolation, this planet is too hot to be habitable but can…
The absorption signals of metastable He in HD 209458b and several other exoplanets can be explained via escaping atmosphere model with a subsolar He/H ratio. The low abundance of helium can be a result of planet formation if there is a…
The escaping atmospheres of hydrogen driven by stellar X-ray and extreme Ultraviolet (XUV) have been detected around some exoplanets by the excess absorption of Ly$\alpha$ in far ultraviolet band. In the optical band the excess absorption…
The recent transit observation of HD 209458 b - an extrasolar planet orbiting a sun-like star - confirmed that it is a gas giant and determined that its orbital inclination is 85 degrees. This inclination makes possible investigations of…
Kowalski & Saumon (2006) identified the missing absorption mechanism in the observed spectra of cool white dwarf stars as the Ly-alpha red wing formed by the collisions between atomic and molecular hydrogen and successfully explained entire…
We have revisited the search for carbon monoxide absorption features in transmission during the transit of the extrasolar planet HD 209458b. We acquired 1077 high resolution spectra at 2 microns using NIRSPEC on Keck II during three…
Escaping atmosphere has been detected by the excess absorption of Ly$\alpha$, H$\alpha$ and He triplet (10830$\rm\AA$) lines. Simultaneously modeling the absorption of the H$\alpha$ and He 10830 lines can provide useful constraints about…
We present a new ultra-violet spectrum of the QSO 0013-004 with 0.9 \AA resolution obtained with the MMT Blue spectrograph. The \upsilon = 0 - 0, 1 - 0, 2 - 0 and 3 - 0 Lyman bands of H_2 associated with the z = 1.9731 damped Ly alpah…
In order to interpret H2 (molecular hydrogen) quasar absorption line observations of damped Ly-alpha systems (DLAs) and sub-DLAs, we model their H2 abundance as a function of dust-to-gas ratio, including H2 self-shielding and dust…
We report the detection of H2 in a zabs= 0.0963 Damped Lyman-{\alpha} (DLA) system towards zem = 0.4716 QSO J1619+3342. This DLA has log N(H I) = 20.55 (0.10), 18.13 < log N(H2) < 18.40, [S/H] = -0.62 (0.13), [Fe/S] = -1.00 (0.17) and the…
We report the discovery of a further line of sight allowing detection of HeII Ly alpha absorption by the intergalactic medium. A HST/STIS survey of 32 bright z ~ 3 quasars selected from the Hamburg Quasar Surveys yielded one detection…
Redshifted L$\alpha$ absorption toward $\alpha$ Cen has been interpreted by Linsky & Wood (1996) and Frisch et al. (1996) as evidence for decelerated interstellar hydrogen piled up on the upstream side of the heliosphere. We utilize newly…
Absorption lines from water, methane and carbon monoxide are detected in the atmosphere of exoplanet HR8799b. A medium-resolution spectrum presented here shows well-resolved and easily identified spectral features from all three molecules…
Traces of photospheric hydrogen are detected in at least half of all white dwarfs with helium-dominated atmospheres through the presence of H alpha in high-quality optical spectroscopy. Previous studies have noted significant discrepancies…
The GJ 436 planetary system is an extraordinary system. The Neptune-size planet that orbits the M3 dwarf revealed in the Ly$\alpha$ line an extended neutral hydrogen atmosphere. This material fills a comet-like tail that obscures the…