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Chi Cygni
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Chi Cygni is a giant-star Mira variable that can reach magnitude 3.5 for some time during a 408.05-day variation period, from magnitude 13.4.
Chi Cygni is a rare class S (S6) star, highly enriched in zirconium, that is about 345 light year...
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10
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R Trianguli
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Maxima of long period variable R Trianguli on the 26th May, 2010 Magnitude: 6.2-11.7 Type: Mira Position (2000): RA 02 37 02.3416, Dec +34 15 51.365
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Blobrana
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9
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NGC 7093
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NGC 7093 is a magnitude ±11.8 open cluster, or group of about 20-24 (magnitude 9-14) stars around the star TYC 3191-591-1, located 5822 ±267 lightyears away in the constellation Cygnus. The age of the cluster is 0.9 ±0.04 billion years old The cluster was discovered by British astronomer John Her...
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Blobrana
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Molecular Cloud W51 IRS2
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A team led by John Lacy of the University of Texas at Austin recently used the instrument TEXES on Gemini North to map the star-forming region IRS2 located deep within the molecular cloud associated with the giant H II region W51. The spatial and spectral performance of TEXES on Gemini allowed the tea...
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6
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Super-Earths
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Astronomers have discovered hundreds of Jupiter-like planets in our galaxy. However, a handful of the planets found orbiting distant stars are more Earth-sized. This gives hope to astrobiologists, who think we are more likely to find life on rocky planets with liquid water. The rocky planets fou...
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21
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NGC1068, M77
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Title: Mid-infrared imaging of NGC1068 with VISIR at the VLT
Authors: E. Galliano, E. Pantin, D. Alloin, P.O. Lagage
High resolution mid-infrared (MIR) images of the central region of NGC1068 (M77) have been obtained with VISIR, the multi-mode MIR instrum...
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17
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Sun's motion
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There's been continual speculation about the connection between the Earth's climate and the local Galactic environment, along with the implications for life. Two researchers have explored any such link in more quantitative detail than in the past.
Ice Age Epochs and the Sun's Path throu...
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Hypervelocity Stars
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1 2 3 4
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Astronomers last year spotted three stars escaping the Milky Way galaxy. On Thursday, researchers announced the discovery of yet two more outbound stars.
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Sigma Orionis cluster
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Title: Stars and brown dwarfs in the sigma Orionis cluster: the Mayrit catalogue Authors: Jose A. Caballero The young sigma Orionis cluster is an indispensable basis for understanding the formation and evolution of stars, brown dwarfs and planetary-mass objects. Our knowledge of its stellar po...
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NGC 6366
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Title: Panchromatic fits to the Globular Cluster NGC 6366 Authors: Fabíola Campos, S. O. Kepler, C. Bonatto We present panchromatic isochrone fits to the colour magnitude data of the globular cluster NGC 6366, based on HST ACS/WFC and SOAR photometric data. Before performing the isochrone fits,...
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Blobrana
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Globular Clusters
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1 2 3 4
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Globular clusters, often regarded as the most boring denizens of our galaxy, have just become a lot more interesting. Rogue, hot stars have been discovered inside them. The tens of thousands of stars that make up each globular cluster were all thought to have formed at the same time, with exactly the...
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36
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Magellanic Clouds
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Title: Young stellar populations in the Magellanic Clouds Authors: A. Vallenari We discuss the young population of stars and clusters in the Magellanic Clouds. We present the discovery of pre-main sequence candidates in the nebula N~11 in the Large Magellanic Clouds using HST ACS photometry. Th...
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24
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NGC 6752
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Title: Nitrogen abundances in giant stars of the globular cluster NGC 6752 Authors: David Yong (1), Frank Grundahl (2), Jennifer A. Johnson (3), Martin Asplund (4) ((1) RSAA, Mt Stromlo Observatory, (2) Univ. of Aarhus, (3) Ohio State University, (4) MPA Garching) We present N abu...
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Blobrana
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5
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(SN) 1987A
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1 2 3 4
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On February 23, 1987, observers saw a star explode in the Large Magellanic Cloud, (a nearby dwarf galaxy).
At about 169000 light years away, it was the closest seen in the past 300 years; and astronomers have continu... < 1.6 x 10^{-14} ergs/s/cm^2 in the wavelength range 2900-9650 Angstroms for any continuum emitter at the centre of the supernova remnant (SNR). It is likely that the SNR contains opaque dust that absorbs UV and optical emission, resulting in an attenuation of ~35% due to dust absorption in the SNR. Taking into account dust absorption in the remnant, we find a limit of L_opt < 8 x 10^{33} ergs/s. We compare this upper bound with empirical evidence from point sources in other supernova remnants, and with theoretical models for possible compact sources. Bright young pulsars such as Kes 75 or the Crab pulsar are excluded by optical and X-ray limits on SN 1987A. Of the young pulsars known to be associated with SNRs, those with ages < 5000 years are all too bright in X-rays to be compatible with the limits on SN 1987A. Examining theoretical models for accretion onto a compact object, we find that spherical accretion onto a neutron star is firmly ruled out, and that spherical accretion onto a black hole is possible only if there is a larger amount of dust absorption in the remnant than predicted. In the case of thin-disk accretion, our flux limit requires a small disk, no larger than 10^{10} cm, with an accretion rate no more than 0.3 times the Eddington accretion rate. Possible ways to hide a surviving compact object include the removal of all surrounding material at early times by a photon-driven wind, a small accretion disk, or very high levels of dust absorption in the remnant.
Read More (PDF)
Photo of the Large Magellanic Cloud and supernova
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Betelgeuse
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Water Vapour on Betelgeuse as Revealed by TEXES High-Resolution 12 Micron Spectra
Authors: N. Ryde, G. M. Harper, M. J. Richter, T. K. Greathouse, J. H. Lacy
The outer atmosphere of the M supergiant Betelgeuse is puzzling. Published observations of different kinds have she...
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