Far‐Ultraviolet Space Telescope Imaging Spectrograph Spectra of the White Dwarf REJ 1032+532. II. Stellar Spectrum

1999 ◽  
Vol 517 (2) ◽  
pp. 850-858 ◽  
Author(s):  
J. B. Holberg ◽  
M. A. Barstow ◽  
F. C. Bruhweiler ◽  
I. Hubeny ◽  
E. M. Green
2015 ◽  
Vol 33 (10) ◽  
pp. 1211-1219 ◽  
Author(s):  
B. Bonfond ◽  
J. Gustin ◽  
J.-C. Gérard ◽  
D. Grodent ◽  
A. Radioti ◽  
...  

Abstract. The aurorae at Jupiter are made up of many different features associated with a variety of generation mechanisms. The main auroral emission, also known as the main oval, is the most prominent of them as it accounts for approximately half of the total power emitted by the aurorae in the ultraviolet range. The energy of the precipitating electrons is a crucial parameter to characterize the processes at play which give rise to these auroral emissions, and the altitude of the emissions directly depends on this energy. Here we make use of far-UV (FUV) images acquired with the Advanced Camera for Surveys on board the Hubble Space Telescope and spectra acquired with the Space Telescope Imaging Spectrograph to measure the vertical profile of the main emissions. The altitude of the brightness peak as seen above the limb is ~ 400 km, which is significantly higher than the 250 km measured in the post-dusk sector by Galileo in the visible domain. However, a detailed analysis of the effect of hydrocarbon absorption, including both simulations and FUV spectral observations, indicates that FUV apparent vertical profiles should be considered with caution, as these observations are not incompatible with an emission peak located at 250 km. The analysis also calls for spectral observations to be carried out with an optimized geometry in order to remove observational ambiguities.


1999 ◽  
Vol 517 (2) ◽  
pp. 841-849 ◽  
Author(s):  
J. B. Holberg, ◽  
F. C. Bruhweiler, ◽  
M. A. Barstow ◽  
P. D. Dobbie

2000 ◽  
Vol 198 ◽  
pp. 161-166
Author(s):  
M. S. Sahu

Space Telescope Imaging Spectrograph (STIS) observations of the D/H ratio in the two velocity components towards G191-B2B are consistent with 1.5 ± 0.1 × 10−5 and do not agree with the values derived using the Goddard High Resolution Spectrograph (GHRS) data. We present some new work on the G191-B2B sightline, and the results we obtain are consistent with those of Sahu et al. (1999).


2003 ◽  
Vol 583 (2) ◽  
pp. 963-984 ◽  
Author(s):  
Thomas R. Ayres ◽  
Alexander Brown ◽  
Graham M. Harper ◽  
Rachel A. Osten ◽  
Jeffrey L. Linsky ◽  
...  

2000 ◽  
Vol 198 ◽  
pp. 485-486
Author(s):  
Wayne Landsman

We review the advantages of using hot white dwarfs (WDs) as probes of the deuterium abundance in the local interstellar medium. We then discuss advantages of the Space Telescope Imaging Spectrograph (STIS) for such observations, as compared with earlier observations with the Goddard High Resolution Spectrograph (GHRS). The GHRS Ly α profile of the white dwarf HZ 43 is probably modified by the hot ‘hydrogen wall’ surrounding the Sun; but despite this complication, the sightline remains a promising one for an accurate determination of the deuterium abundance in the local interstellar medium.


2004 ◽  
Vol 217 ◽  
pp. 192-193
Author(s):  
Shinn Jong-Ho ◽  
Seon Kwang-Il ◽  
Lee Dae-Hee ◽  
Min Kyoung-Wook

We analyze CO and H2 absorption lines of the foreground molecular cloud in the Carina nebula. We use HST-STIS (Hubble Space Telescope - Space Telescope Imaging Spectrograph) & IUE (International Ultraviolet Explorer) INES data to analyze the A-X (v=0→2) absorption band of CO for several hot stars toward the Carina nebula, while 9 stars of them have FUSE (Far Ultraviolet Spectroscopic Explorer) spectra to analyze the (v=0→4) vibrational band in the Lyman series of H2. The column densities of CO and H2 varies in the vicinity of N(CO) ~ 1013cm−2 and N(H2) ~ 1019cm−2, respectively. The resultant CO-to-H2 abundance ratio is about 10−6. We investigate the variation of the abundance ratio according to the relative position of the target stars to morphology the molecular cloud in the Carina nebula.


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