Astronotes Armagh Planetarium's Stellar Blog! ... Comets and Asteroids . ... Image credit:ESO/J.Emerson/VISTA. ... However others are less pessimistic and it has even been claimed that the mysterious ?Wow! signal? received in 1977 originated from the direction M55.б  Sadly, this still unexplained pulse of radio energy originated from a location rather to the northwest of M55 so I doubt if the source was this cluster (if indeed the signal was genuinely of extraterrestrial origin). ... Mysterious Wow! ...

... Credit: N. A. Sharp ( NOAO ), AURA , NSF Explanation: Open clusters of stars can be near or far, young or old, and diffuse or compact. ... An older and more compact open cluster, NGC 2158 , is visible above on the lower right. ... NGC 2158's bright blue stars have self-destructed , leaving cluster light to be dominated by older and yellower star s. Both clusters are visible toward the constellation of Gemini -- M35 with binoculars and NGC 2158 with a small telescope. ... Star Cluster Messier 67 . ...

... 2000 October 22 . Wild Duck Open Cluster M11 . ... Explanation: Many stars like our Sun were formed in open clusters . The above open cluster, M11 , contains thousands of stars and is just over three thousand light years distant. ... Open clusters , also called galactic clusters, contain fewer and younger stars than globular clusters . Also unlike globular clusters, open clusters are generally confined to the plane of our Galaxy . ... About APOD | ...

home publications > mercury . ... Big Clusters, Tiny Galaxies . ... Astronomers struggle to understand why giant star clusters form in the tiniest of galaxies . ... These clusters are probably young versions of globular clusters, but they are commonly called super star clusters. Seven dwarf galaxies within 16 million light-years have formed super star clusters, with one of these galaxies, NGC 1569, possessing two young clusters. ... Super star clusters have a lot to tell us about star formation. ...

... Kalirai and Harvey Richer of the University of British Columbia led the study, which began as an investigation of a globular star cluster in the Milky Way galaxy known as NGC 6397. ... Within the population of stars and galaxies behind NGC 6397, the Hubble image revealed a large elliptical galaxy that contains several hundred globular clusters. ... In fact, a single giant star in NGC 6397 appears 10 million times brighter than one of the distant globular clusters. ...

... Most stars form in clusters, so the simple picture of star formation needs to incorporate the impact that young stars have on their environments, and each other. One region we study is NGC 1333, shown to the left as seen by the Spitzer Space Telescope. This is a тАЬproto-typicalтАЭ star-forming region located тАЬonlyтАЭ 1000 light years away in the direction of the constellation Perseus. ... Copyright 2015 Adele Plunkett. ...

... STScI-PRC00-25 A DYING STAR IN GLOBULAR CLUSTER M15 The globular cluster Messier 15 is shown in this color image obtained with the NASA Hubble Space Telescope's Wide Field Planetary Camera 2 (WFPC2). ... Known as Kuestner 648, this was the first planetary nebula to be identified in a globular cluster. ... At the present time, the most massive stars remaining in M15 have about 80 percent of the mass of our Sun, a fact that makes the existence of a planetary nebula like K 648 something of a mystery. ...

Stellar Clusters are very useful laboratories for empirically studying stellar evolution. ... All cluster stars are at the same distance . All cluster stars have the same physical age . ... CM diagram Young Cluster In this case we see the Main Sequence fully represented. The blue dots represent massive stars with short main sequence lifetimes. ... Thus, identifying the most massive star which is still on the main sequence is an effective means of determining the age of a stellar cluster. ...

... 1st Announcement IAU Symposium 312 Star Clusters and Black Holes Across Cosmic Time, Beijing, China, Aug. 25-29, 2014 . ... SUBJECT: 1st Announcement IAU Symposium 312 Star Clusters and Black Holes Across Cosmic Time, Beijing, China, Aug. 25-29, 2014 . ... which will be held in Beijing, P.R. China, from August 25-29, 2014, hosted by Chinese Academy of Sciences . ... China), . ... 1st Announcement IAU Symposium 312 Star Clusters and Black Holes Across Cosmic Time, Beijing, China, Aug. ...

... Globular cluster NGC 2808, elliptical galaxy NGC 2986, and the Sextans Dwarf . ... Astronomy for Kids . ... Astronomy 101 . ... Astronomy Foundation . ... Do globular clusters form in a galaxy's halo or migrate in from outside? If the latter, how? ... The Milky Way Galaxy has a system of roughly 150 globular clusters, which are all older than 9 billion years. ... Get instant access to subscriber content on Astronomy.com! ... If you are already registered on Astronomy.com, please log in below. ...

... In the past used to check pn/ MOS cross calibration Example of old vs new pn/ mos Residuals in the form of ratio data / model for PN data on MOS best fitting model Example of old vs new pn/ mos Residuals in the form of ratio data / model for PN data on MOS best fitting model ACIS S3 vs EPIC pn · · Same thing, only now we compare Chandra ACIS S3 with ... Flux cross-cal · · The new HRMA calibration impacts on the ACIS/EPIC flux cross calibration. ...

... Bad Astronomy . ... Bitesize Astronomy . ... The next step up are true clusters, called open clusters . Open clusters (sometimes misleadingly called "galactic clusters") are groups of stars ranging in size from a few dozen stars up to tens of thousands. ... The youngest is about 1 or 2 million years old, while the oldest is about 6 or 7 billion years, making it just older than our own solar system. ... So by looking at the stars in the cluster we can tell pretty well how old they are. ...

Many intermediate-age star clusters in the Magellanic Clouds exhibit very unusual features in their colour-magnitude diagrams that suggest they may have formed their stars over periods spanning hundreds of millions of years per cluster. ... Nonetheless, this interpretation is enticing in the context of the formation of ancient globular clusters, which almost always exhibit puzzling abundance patterns that apparently require multiple episodes of star formation to explain. ...

... The routines implemented are CLUSTER which has 8 options for hierarchical clustering and PARTITION which carries out non--hierarchical clustering. ... The former is non--hierarchical clustering or partitioning. The latter is hierarchical clustering. Brief consideration will show that a sequence of n-1 agglomerations are needed to successively merge the two closest objects and/or clusters at each stage, so that we have a set of n (singleton) clusters, n-1 clusters, ..., 2 clusters, 1 cluster. ...

The X-ray Fundamental Plane of Clusters of Galaxies Yutaka Fujita National Astronomical Observatory, Japan We analyze the relations among central gas density, core radius, and temperature of X-ray clusters by plotting the observational data in the three-dimensional (log  gas;0 , log r c , and log T gas ) space and nd that the data lie on a 'fundamental plane'. ... The two parameters describing the plane are formation redshift and temperature of clusters. ...

... This paper ( Burke et al. 2003 ) describes the creation of one such catalogue - the Southern Serendipitous High-redshift Archival ROSAT Cluster (SHARC) survey - which covers an area of 17.7 deg 2 and consists of 32 clusters with redshifts between 0.05 and 0.7 and X-ray luminosities between 7 x 10 42 and 4 x 10 44 erg/s: the high-redshift subsample contains 16 clusters with = 0.3 and X-ray luminosities greater than 2 x 10 43 erg/s (luminosities are quoted for the 0.5 - 2.0 keV energy band). ... 1997 ...

A Canadian and American team of Astronomers have used the 305-m wide Arecibo radio dish, the world's largest and most sensitive radio telescope, to uncover a dozen new super-fast-spinning pulsars. The team directed their search for these rare and exotic stars by pointing the Arecibo radio telescope towards massive star clusters, called Globular Clusters, orbiting our Milky Way galaxy. ... One of the most exotic residents in the Globular cluster system are the millisecond pulsars. ...

... We found that 10 metal-poor globular clusters are greately distinguished for anomalously small masses on the "destruction rate-mass" plain. As it turned out, these poor clusters, situated 15 kpc farther from the Galactic centre, are somewhat younger than the bulk of the metal-poor globulars, and have anomalously red horizontal branches. ... At the same time, deficiency of distant massive clusters is noticeable with increasing distance from the galactic centre. ...

... With the stars gamma Can and delta Can , it forms another asterisms called " the Asses and the Manger ". ... Formed by the stars delta Ori, epsilon Ori and zeta Ori ; in Latin America it is called the " Three Marys ". ... Built by the four stars alpha UMa, beta UMa, gamma UMa and delta UMa . ... Formed by the four stars alpha Del , beta Del , gamma Del and delta Del . ... Also on Orion; the belt stars ( delta Ori , epsilon Ori and zeta Ori ), the sword and eta Ori build up this asterism. ...

... Gravitational microlensing of giant luminous arcs: . a test for compact dark matter in clusters of galaxies . ... This paper discusses a new test for the detection of stellar mass compact dark matter in galaxy clusters by observing its gravitational lensing influence on the surface brightness of giant luminous arcs. ... With the advent of the Next Generation Space Telescope, cluster dark matter in the form of compact objects will induce a ubiquitous `shimmering' of the giant arcs. ... Giant Arcs . ...