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Evolution of the 3.3-μm emission feature in the Red Rectangle
Medium-resolution infrared spectroscopic observations of the biconicalRed Rectangle nebula in the region of the 3.3-μm unidentifiedinfrared (UIR) emission band are reported. The data were recorded atUKIRT using CGS4 and have allowed the peak wavelength, width, profileand intensity of the 3.3-μm feature to be investigated as a functionof offset from the central star HD 44179. Analysis of the profile of thefeature along the north-western bicone interface shows an evolution fromType 2 to Type 1 in the classification of Tokunaga et al. The 3.3-μmband recorded on-star shows a close fit to a Lorentzian profile,possibly suggesting a single class of carriers. Subtraction of theLorentzian fit to the on-star spectrum from the spectrum at each offsetreveals a new `3.28'-μm emission feature that grows in intensityrelative to the main 3.3-μm band as a function of distance from thecentral star. The 3.28-μm emission band at large offset appears tocorrespond well in wavelength and FWHM with an absorption feature seentowards the Galactic Centre.
| Far-ultraviolet stellar photometry - A field in Monoceros
FUV photometry of stars in a field in Monoceros in the wavelength rangefrom 1230 to 1600 A has been carried out using data from anelectrographic Schmidt camera carried on a sounding rocket. Ultravioletmagnitudes were extracted for 602 objects in the field. Fifty-eightpercent were tentatively identified with visible stars using the SIMBADdata base while another 25 percent are blends of objects too closetogether to separate with our resolution. Eleven of the UV objectscoincide with parts of the star clusters NGC 2169, NGC 2244, and NGC2264 in which individual stars cannot be resolved. As in previousstudies, the majority of the identified ultraviolet sources areidentified with early-stars. However, there are a significant number forwhich no such identification was possible, and we suggest that many ofthese are nearby white dwarfs.
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Osservazione e dati astrometrici
| Costellazione: | Orione |
| Ascensione retta: | 06h02m38.83s |
| Declinazione: | +12°40'16.4" |
| Magnitudine apparente: | 7.932 |
| Moto proprio RA: | 2.2 |
| Moto proprio Dec: | -3.8 |
| B-T magnitude: | 7.905 |
| V-T magnitude: | 7.93 |
Cataloghi e designazioni:
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