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Model Photospheres for Late-Type Stars from the Inversion of High-Resolution Spectroscopic Observations: Groombridge 1830 and ɛ Eridani
Lambert, David L.; Allende Prieto, Carlos; García López, Ramón J. +1 more
An inversion technique to recover LTE one-dimensional model photospheres for late-type stars, which was previously applied to the Sun by Allende Prieto et al. in 1998, is now employed to reconstruct, semiempirically, the photospheres of cooler dwarfs: the metal-poor Groombridge 1830 and the active star of solar metallicity ɛ Eridani. The model atm…
On the relationship between shift and intensity of ultraviolet lines in coronal holes and the quiet Sun
Solanki, S. K.; Schühle, U.; Rüedi, I. +1 more
We study the relationship between wavelength shifts and intensities of chromospheric, transition-region and coronal ultraviolet emission lines in polar coronal holes and in the normal quiet Sun using SUMER data. Within coronal holes almost all the lines showing the network and formed above 30 000 K show a correlation between blueshifts and brightn…
Long-term photometry of the Wolf-Rayet stars WR 137, WR 140, WR 148, and WR 153
Altmann, M.; Panov, K. P.; Seggewiss, W.
In 1991, a long term UBV-photometry campaign of four Wolf-Rayet stars was started using the 60 cm telescope of the National Astronomical Observatory Rozhen, Bulgaria. Here we report on our observational results and discuss the light variations. The star WR 137 was observed during 1991 - 1998. No indications of eclipses were found, though random li…
The strange case of theta 1 Orionis
Stickland, D. J.; Lloyd, C.
We review the binary properties of the bright Orion Trapezium star theta^1 Ori A and include radial velocities from IUE in a new orbital solution; meanwhile, times of primary minimum are used to determine a new ephemeris. With these revised parameters, we strongly encourage further observations, especially a search for secondary minimum. Probably …
Ballistic Reconstruction of HST Observations of Ejecta Motion Following Shoemaker-Levy 9 Impacts into Jupiter
Ballester, Gilda E.; Clarke, John T.; Hammel, Heidi B. +1 more
We present a detailed analysis of Hubble Space Telescope (HST) Wide Field and Planetary Camera 2 (WFPC 2) images of the first 25 min of the impacts of Comet Shoemaker-Levy 9 fragments A and G with Jupiter and the post impact ejecta patterns observed 1-2 h after each impact event, with a brief analysis of the available observations of the first 25 …
Clustering of galaxies at faint magnitudes
Freudling, W.; Fynbo, J. U.; Möller, P.
Significant uncertainties exist in the measured amplitude of the angular two-point correlation function of galaxies at magnitudes I~26 and fainter. Published results from HST and ground-based galaxy catalogs seem to differ by as much as a factor of 3, and it is not clear whether the correlation amplitude as a function of magnitude increases or dec…
3 Micron Imaging of the Hubble Deep Field
Dickinson, Mark; Djorgovski, S. G.; Hogg, David W. +4 more
Images of the Hubble Deep Field (HDF) at 3.2 µm, taken with the 10 m Keck Telescope, are presented. The images cover a total area of ~2.5 arcmin2. To a 5 σ limit of [3.2]tot~17.5 mag (Vega relative), 11 sources are detected, nine of which are extragalactic. The integrated galaxy number counts are therefore ~1.3x104…
Far-Ultraviolet Absolute Flux of α Virginis
Bowyer, Stuart; Edelstein, Jerry; Cobb, Jeff +7 more
We present the far-ultraviolet spectrum of α Virginis taken with Espectrógrafo Ultravioleta extremo para la Radiación Difusa (EURD) spectrograph on board MINISAT-01. The spectral range covered is from ~900 to 1080 Å with 5 Å spectral resolution. We have fitted Kurucz models to IUE spectra of α Vir and compared the extension of the model to our wav…
New infrared object in the field of the SMC cluster NGC 330
Sauvage, M.; Tanabé, T.; Vansevičius, V. +1 more
We report ISO (Infrared Space Observatory) observations of a new infrared source discovered in the vicinity of the young populous cluster NGC 330 in the Small Magellanic Cloud. The object was observed with ISOCAM at 4.5, 6.75 and 11.5 mu m and shows a prominent mid-infrared excess, indicating the presence of a dust shell. The available observation…
Unusual spectral energy distribution of a galaxy previously reported to be at redshift 6.68
Chen, Hsiao-Wen; Lanzetta, Kenneth M.; Pascarelle, Sebastian +1 more
Observations of distant galaxies are important both for understanding how galaxies form and for probing the physical conditions of the Universe at early times. It is, however, very difficult to identify galaxies at redshifts <italic>z</italic> > 5, because they are so faint and have few spectral characteristics. We previously report…