Astronomy Picture of the Day . ... B.J. Mochejska , J. Kaluzny ( CAMK ), 1m Swope Telescope Explanation: This color "picture" of globular star cluster M55 may not look like any star cluster you've ever seen. ... In the picture, a Color Magnitude Diagram (CMD), M55's individual stars are represented as dots whose color indicates relative temperature, red (cool) to blue (hot). ... Publications with keywords: color - magnitude - diagram - cmd - m55 - star - stellar evolution . ...

... 2001 February 7 . Distant Open Cluster M103 . ... Explanation: Bright blue stars highlight the open cluster known as M103 . The gas clouds from which these stars condensed has long dispersed. ... In fact, a formerly blue star has recently evolved off the main sequence and is visible above as the red giant star near the cluster center. In general, yellow stars like our Sun are usually less bright and hence less prominent in open clusters than their massive blue cousins. ... About APOD | ...

Fundamental parameters and time evolution of mass loss are investigated for post-main-sequence stars in the Galactic globular cluster 47 Tucanae (NGC 104). ... We confirm the cluster's distance as d = 4611+213 -200 pc and age as 12 ТБ 1 Gyr. Horizontal branch models appear to confirm that no more red giant branch mass loss occurs in 47 Tuc than in the more metal-poor Я? Centauri, though difficulties arise due to inconsistencies between the models. ...

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. ...

... About ATMoB . ... The Observing Committee is starting an Observing Awards Program to promote observing among the membership of the Amateur Telescope Makers of Boston. ... Participant must be a current member of the Amateur Telescope Makers of Boston . ... To qualify for your Observing Award Certificate, turn in your worksheet and drawings to an ATMoB Observing Committee member or observing@atmob.org . ... This Excel sheet has useful macros. ... Copyright (c) Amateur Telescope Makers of Boston, Inc. ...

... Stellar cinders . Born-again stars . ... Heavyweight Stars . ... What will happen inside the Sun and why? ... These are questions about "stellar evolution", the history of stars as they are transformed by nuclear processes deep inside. ... Most of what we know about stellar evolution comes from computer models of stars. ... We learn about the evolution of high-mass stars from HR diagrams of young galactic open clusters, and the evolution of low-mass metal-poor stars from old globular clusters. ...

... Each day a different image or photograph of our fascinating universe is featured, along with a brief explanation written by a professional astronomer. February 5, 1996 . COBE Dipole: Speeding Through the Universe . Credit: NASA , COBE , DMR , Four-Year Sky Map . ... The Milky Way Galaxy orbits in the Local Group . ... The map indicates that the Local Group moves at about 600 kilometers per second relative to this primordial radiation . ... About APOD | ...

Regions designation | Regions models | ASCII files description . The real time visibility of the IB_TAIL relative to the Evpatoria and Panska Ves . ... The real time regions passing . ... The IB_TAIL geocentric distance as a function of the Moscow time (MT = UT + 3h) (Plot) . Geomagnetic local time in the IB_TAIL position as a function of the MT (Plot) . The IB_TAIL orbital data ASCII files . ... INTERBALL mission  ...

... The Pleiades star cluster, also known as the Seven Sisters and Messier 45, is a conspicuous object in the night sky with a prominent place in ancient mythology . ... The stars in the Pleiades are thought to have formed together around 100 million years ago, making them 1/50th the age of our sun, and they lie some 130 parsecs (425 light years ) away. ... Data for these stars are listed in a table below. ... Yes . ... WEBDA Pleiades cluster data . ... M45: The Pleiades Star Cluster (2007 November 18) ...

... The exercises are now available on the web and in six booklets (100 pages in total), titled: . ... Exercise 1: Measuring the Distance to Supernova 1987A", . Exercise 2: The Distance to Messier 100 as Determined by Cepheid Variable Stars", . Exercise 3: Measuring the Distance to the Cat's Eye Nebula" and . Exercise 4: Measuring a Globular Star Cluster's Distance and Age". ... More exercises will follow in the future. ... Exercise 3 - Measuring the Distance to the Cat's Eye Nebula . ...

Giant stars are rare because . ... In a color-magnitude diagram of a star cluster, the blue end of the main sequence is useful for defining the age of the cluster because . a) blue stars are not affected by extinction and reddening by dust. b) stars just slightly brighter and redder are just now evolving off the main sequence to become giants. c) older, metal-poor stars are blue. d) the hottest stars are the oldest stars in a cluster. ... 2) Some idea. 3) Good idea. ...

... We have made observations of the Perseus cluster with the Westerbork Telescope at 610 MHz. ... Several newly detected sources are identified with cluster galaxies. ... No evidence is found for the existence of the previously reported ~ 65'x25' cluster halo, 3C 84B. Key words: radio galaxies - clusters - tailed radio sources buoyancy The Perseus Cluster of galaxies is one of the most fascinating systems accessible to extragalactic astronomers. ...

... A document window is shown, with 8 lines (numbered 1 to 8), each 24px high. The text of the "outer" box (at the end of line 1, halfway into line 2, and halfway into line 3) is shifted upward 12px. The text of the "inner" box, thought shifted upward as well, has been relatively positioned so that it lies in its normal flow position at the end of line 2. ... The lines, as they appear in the image, contain: Start 1 Beginning of body contents. 2 of outer contents. Inner contents. ...

... 1) A new bright galaxy of the Local Group VV124 (UGC4879) is found. ... Kopylov A.I., Tikhonov N.A., Fabrika S.N., Drozdovsky I.O., Valeev A.F., MNRAS Lett, V. 387, Issue 1, L45, 2008. ... For systems of galaxies in the regions of the Hercules and Leo superclusters the dwarf-to-giant ratio of galaxies in the r-band is evaluated, and it is found that this ratio increases with increasing X-ray luminosity at log L X > 43.5 erg/s. Kopylova F.G., Kopylov A.I., Ast. ... Kopylova F.G., Kopylov A.I., Ast. ...

... Science User Portal . ... ESO, the European Southern Observatory . ... Travel and Contacts . Travel to ESO Headquarters . ... Travel to E-ELT Armazones . ... Green ESO . ... Survey Telescopes . ... Star Clusters . ... Stars@ESO . ... Astronomers have detected a new faint companion to the star HD 3651, already known to host a planet. ... The separations (top) and position angles (bottom) of the companion with respect to the host star is shown here over a three year period. ... Related releases: . ...

ABSOLUTE PROPER MOTIONS OF 331 OPEN CLUSTERS . ... The proper motions of stars in the fields of 331 open clusters were taken from Four-Million Star Catalog (4M-catalog) of positions and proper motions (Volchkov et al. ... The absolute proper motions for 21 young open clusters have been derived by comparison of precise relative proper motions of individual stars and their corresponding absolute proper motions. ... Sign of proper motions in RA . ... 0.0001 arcsec/yr . ... rms error in RA proper motion . ...

... The overall globular cluster population is divided by gap in the metallicity function at [Fe/H]=-1.0 into two discrete groups with well-defined maxima at [Fe/H]=-1.60?0.03 dex, and -0.60?0.04 dex. ... Clusters with extremely blue horizontal branches occupy a spherical volume of radius ~ 9 kpc, have high rotational velocities ( V rot =77?33 km/s), have substantial and equal negative radial and vertical metallicity gradients, and are, on average, the oldest group (the old-halo subsystem). ...

... BLUE STRAGGLER STARS are unusually hot and bright stars found in the cores of ancient star clusters known as globulars. ... BACKGROUND (from wikipedia): Blue straggler stars are stars in open or globular clusters that are hotter and bluer than other cluster stars having the same luminosity. ... There is evidence in favor of this view, notably that blue straggler stars appear to be much more common in dense regions of clusters, especially in the cores of globular clusters. ...

... Subject and Problems of Stellar Astronomy. ... Plane of Galaxy, Methods of Its Location Determination. ... Stars Distances. ... Other Methods of Stars Distances Determination. ... Tangential Velocities, Their Determination by Self-Motions. ... Determination of Solar Apex and Spatial Velocity by Radial and Spatial Velocities of Stars. ... Features of Orientation and Parameters of Peculiar Stellar Velocities Ellipsoid. ... General and Selective Light Absorption in Galaxy. ... Darc Clouds in Galaxy. ...

A typical radio dataset might be a 3-dimensional "cube" named AURORA, with axes RA, DEC and FREQ. ... These can be specified by giving the axis name(s) and grids for each subset. For instance, AURORA specifies the whole 3-dimensional ``cube''; AURORA FREQ 3 specifies the subset FREQ=3 (i.e. the RA-DEC plane at FREQ grid 3) of the set AURORA. ... Specifying only the axis name, and no grids, selects all subsets along that axis: AURORA FREQ selects all RA-DEC planes in AURORA. ... axis centre. ...