相关论文: Internal and external shock fronts in He2-104

We present a first emission line analysis of a high resolution X-ray spectrum of the stellar wind of theta 1 Ori C obtained with the High Energy Transmission grating Spectrometer onboard the Chandra X-ray Observatory. The spectra are…

The structure and spectrum of the accretion shock have been self-consistently simulated for a wide range of parameters typical for Classical T Tauri Stars (CTTS). Radiative cooling of the shocked gas was calculated, taking into account the…

Previously-unexplored diagnostics of O IV in the extreme ultraviolet region 260-280 A are used to derive a temperature and density for a solar flare kernel observed on 2012 March 9 with the Extreme ultraviolet Imaging Spectrometer on the…

In this paper we present high resolution 4.7micron spectra of the isolated Herbig Be star HD100546. HD100546 has been the subject of intense scrutiny because it is a young nearby star with a transitional disk. We observe the Delta v=1…

The prospects for using asteroseismology of rapidly oscillating Ap (roAp) stars are hampered by the large uncertainty in fundamental stellar parameters. Results in the literature for the effective temperature (Teff) often span a range of…

The outer ejecta is part of the nebula around Eta Carinae. They are filamentary, shaped irregularly and larger than the Homunculus, the central bipolar nebula. While the Homuculus is mainly a reflection nebula, the outer ejecta is an…

We derive the stellar parameters of a sample of Galactic early-O type stars by analysing their UV and Far-UV spectra from FUSE (905-1187A), IUE, HST-STIS and ORFEUS (1200-2000A). The data have been modeled with spherical, hydrodynamic,…

FUSE ultraviolet spectra of 8 giant and supergiant stars reveal that high temperature (3 X 10^5 K) atmospheres are common in luminous cool stars and extend across the color-magnitude diagram from Alpha Car (F0 II) to the cool giant Alpha…

We present deep spectroscopic (3600 - 24700 A) X-shooter observations of the bright Herbig-Haro object HH1, one of the best laboratories to study the chemical and physical modifications caused by protostellar shocks on the natal cloud. We…

Past studies based on optical spectroscopy suggest that the five $\omega$ Cen pulsators form a rather homogeneous group of hydrogen-rich subdwarf O stars with effective temperatures of around 50 000 K. This places the stars below the red…

The high brightness temperatures, $T_\mathrm{b}\gtrsim 10^{13}$ K, detected in several active galactic nuclei by RadioAstron space VLBI observations challenge theoretical limits. Refractive scattering by the interstellar medium may affect…

Optical high-resolution spectra of the R Coronae Borealis star V CrA at light maximum and during minimum light arediscussed. Abundance analysis confirms previous results showing that V CrA has the composition of the small subclass of R…

Spatially resolved H$\alpha$ and [N{\sc ii}] line profiles have been obtained over striking features in the outer regions of the Eta Carinae nebula. The highly irregular outer `shell' of low ionization, [N{\sc ii}] bright, knots has been…

The nebula around eta Carinae consists of two distinct parts: the Homunculus and the outer ejecta. The outer ejecta are mainly a collection of numerous filaments, shaped irregularly and distributed over an area of 1arcminx1arcmin. While the…

Extreme helium stars (EHe) with effective temperatures from 8000K to 13000K are among the coolest EHe stars and overlap the hotter R CrB stars in effective temperature. The cool EHes may represent an evolutionary link between the hot EHes…

Infrared radiation emitted from a planet contains information about the chemical composition and vertical temperature profile of its atmosphere. If upper layers are cooler than lower layers, molecular gases will produce absorption features…

A main source of bias in transmission spectroscopy of exoplanet atmospheres is magnetic activity of the host star in the form of stellar spots, faculae or flares. However, the fact that main-sequence stars have a chromosphere and a corona,…

Exoplanets that receive stellar irradiance of approximately Earth's or less have been discovered and many are suitable for spectral characterization. Here we focus on the temperate planets that have massive H2-dominated atmospheres, and…

Detection of molecules using infrared spectroscopy probes the conditions and compositions of exoplanet atmospheres. Water (H2O), methane (CH4), carbon dioxide (CO2), and carbon monoxide (CO) have been detected in two hot Jupiters. These…

We present thermal-IR images of three extreme bipolar objects, M2-9, Mz3, and He2-104. They are bipolar planetary nebulae with bright central stars and are thought to be powered by symbiotic binary systems. The mid-IR images spatially…