Spitzer Space Telescope mid-infrared spectroscopy has been obtained for 15 carbon-rich protoplanetary nebulae (PPNe) in the Large Magellanic Cloud (LMC) and for two other such stars in the Small Magellanic Cloud (SMC). Of these 17 PPNe, the unidentified 21 ѕ®m feature is strong in 7 spectra, weak in 2 spectra, and very weak or questionable in 4 spectra. ... The remaining two objects show typical carbon-rich PPNe spectra with no 21 ѕ®m features. ...

Figure 1: An averaged OH 1612-MHz spectral profile of V1018 Sco, from 36 separate epochs of observations at Parkes. ... V1018 Sco (IRAS 17317-3331, OH354.88-0.54) is a well known OH/IR star with strong infrared and radio maser emission. The OH 1612-MHz maser spectrum of V1018 Sco, shown in Figure 1, has a double-peaked profile that is characteristic of asymptotic giant branch (AGB) stars where the maser emission occurs from the outer regions of an expanding circumstellar envelope. ...

... Right: cold gas traced by [CII] emission (red) accreting onto a primeval galaxy (green) at z=7.1 ( Maiolino et al. 2015 ) (image credit: ALMA Press Release ) . ... 2010 , Cicone, Maiolino et al. ... 2012 , Cicone, Maiolino et al. ... Right: observed distribution of the average stellar metallicities of passive and star forming galaxies in the local universe, supporting starvation/strangulation as primary quenching mechanism in low/intermediate mass galaxies ( Peng, Maiolino, Cochrane 2015 ). ...

... Star Atlas . ... solar system . ... stars . ... Observe the Solar System . ... What factors determine if a massive star (say, 100 solar masses) forms instead of a Sun-like star? ... Stars of all masses form from dense clumps within exceptionally cold molecular clouds. ... Massive stars tend to form at the centers of high-mass reservoirs of gas. Get instant access to subscriber content on Astronomy.com! ... A gamma-ray burst hints that LIGO's double black holes started as one massive star . ...

... 2016 February 5 . Massive Stars in NGC 6357 . ... Explanation: Massive stars lie within NGC 6357 , an expansive emission nebula complex some 6,500 light-years away toward the tail of the constellation Scorpius . In fact, positioned near center in this ground-based close-up of NGC 6357, star cluster Pismis 24 includes some of the most massive stars known in the galaxy, stars with nearly 100 times the mass of the Sun. ... About APOD | ... NASA Official: Phillip Newman Specific rights apply . ...

... Laboratory and theoretical modelling of the UV bump on the interstellar extinction curve is a very popular topic in dusty investigations. ... feature is illustrated by Fig. 10 where the profiles were calculated using the model of graphite spheres. Figure 10: Normalized extinction efficiencies for graphite spheres. ... The lower panel shows the summary extinction of two graphite spheres with radii and (from upper panel) taken in equal proportions. ...

... The J, H and K bands are characterized by a bright background, such a background is mainly due to the emission of atmospheric lines and of thermal radiation. ... If the source cover a large fraction of the slit, spectra off-source must be observed to adequately sample the sky background. ... The on chip integration time (time spent in each position of the slit) must not exceed 40 seconds in J and H bands and 60 seconds in K band. ... We suggest a sequence of 10 for each elementary integration time. ...

... Contacts . 2012: . ... We refined the fundamental parameters of the components, the orbital periods, and the conditions of photospheric heating of the secondary component by the ultraviolet radiation of the hot component. ... The observations of the star clusters associated with ultra-luminous x-ray sources (ULXs) in four galaxies on the 6-meter and VLT telescopes have shown that all the ULXs are located within 200pc of very young star clusters (younger than 5 million years). ... Archive . ...

Next: Radial velocity of the Up: Optical spectrum of IRAS04296 Previous: Observations and spectra reduction . ... However, molecular emission features are only very rarely observed in the optical spectra of PPNe. ... On the other hand, it is well known that cometary nuclei spectra show prominent Swan band emission. In both spectra of IRAS04296 we have discovered strong emission in the (0;0) and (0;1) bands of the Swan system of the molecule. ... Now consider the case of IRAS04296. ...

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