... Abstract . ... Quasars at Redshift z=6 and Early Star Formation History . ... The Red Sequence at 1.3 . ... Coronagraphic Polarimetry of HST-Resolved Debris Disks . ... Exploring the Scaling Laws of Star Formation . ... ACS imaging of the "Little Red Spot" from April, 2006 . ... Using the High Resolution Camera (HRC) on ACS, HST obtained a series of images of the `Little Red Spot' in early 2006. ... Observations of the A0 star, HD 32297, and the G3 dwarf, HD 61005, are scheduled in the coming week. ...

Deep Time: Earth's history and future By Colin Johnston, Armagh Planetarium Earth 4.54 billion years ago Forms in Sun's protoplanetary disc S un Elsewhere in Solar System Other planets form. ... Hot and airless Sun a subgiant, diameter 1.5 its current value, 2 6.4 billion years from no w ? ... Earth cools 20 million years later? ... Core temperature about 55 million°C, helium flash, followed by the Sun shrinking Sun is 10 times its current diameter, luminosity 20-50% current value. ...

... Globular cluster NGC 2808, elliptical galaxy NGC 2986, and the Sextans Dwarf . ... What would cause Earthт??s orbit to become more circular instead of its present elliptical orbit, and has this ever happened before? ... Gravitational interactions among the planets cause the ellipticities of the orbits to oscillate periodically by a few percent over millions of years. Get instant access to subscriber content on Astronomy.com! ... If you are already registered on Astronomy.com, please log in below. ...

Astronomy Picture of the Day . M81: A Bulging Spiral Galaxy . ... The blue regions in this picture - representing ultraviolet light - highlight regions of bright young stars and star formation and appear rare than in M74 and M33. The red regions - representing the visible light - show a large population of older, less massive stars. Ancient Cratered Plains on Ganymede . ... M74: A Grand Design Spiral Galaxy . ... The spiral galaxy M33 is a mid-sized member of our Local Group of galaxies. ...

In this new series we present observations and modelling of spectral lines formed in main sequence star chromospheres (from G0 to M8). in this paper, we discuss the Hydrogen line formations in very active dMe stellar chromospheres. ... Our final model atmosphere is described in the next paper in this series. ... We found that observations are best reproduced by a chromospheric structure including a constant temperature gradient (in a log(M) scale) in the chromosphere and transition region. ...

... I present results from several seasons of photometric observations of X--ray sources in the Orion OB1a and OB1b star formation regions. The initial goal was to measure the rotational periods of several dozen pre--main sequence (PMS) stars. ... Infrared and optical data confirm that 90% of the X--ray sources are PMS and about 10% of the PMS stars may have disks. ... I find rotation periods for five stars at confidence of greater than 99.9/ greater than 99/ at much lower confidence. ...

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. ...

... November 27, 1996 . Storm Clouds Over Jupiter . Credit: The Galileo Project , JPL , NASA . Explanation : Storm clouds , similar to the familiar cumulonimbus thunderheads of Earth , appear to be present on Jupiter. ... The false colors represent altitude. Low altitude clouds are blue, high, thick clouds are white and high, thin clouds are pink, with the box at the upper right containing the high cloud features likened to the storm clouds of Earth. ... About APOD . ...

... The physical data page presents data about the objects themselves. ... ( 0 ) Mercury I Sun 57910 87.97 7.00 0.21 - - ( 0 ) Venus II Sun 108200 224.70 3.39 0.01 - - ( 0 ) Earth III Sun 149600 365.26 0.00 0.02 - - ( 0 ) Mars IV Sun 227940 686.98 1.85 0.09 - - ( 0 ) Jupiter V Sun 778330 4332.71 1.31 0.05 - - ( 0 ) Saturn VI Sun 1429400 10759.50 2.49 0.06 - - ( 0 ) Uranus VII Sun 2870990 30685.00 0.77 0.05 Herschel 1781 ( 0 ) Neptune VIII Sun 4504300 60190.00 1.77 0.01 Adams ( 9 ) 1846 ( 0 )...

... ESO, the European Southern Observatory . ... Video News Releases . ... New on eso.org . ... ESO News . ... The Comet€аMcNaught€а2007 . ... SL-9 and Jupiter - 1994 . ... The newest results of the associated investigations will be discussed at a scientific Workshop at ESO and presented to the media at a subsequent Press Conference on February 15, 1995. ... This conference will be held at the end of the Workshop and will provide a thorough overview of the latest results, as presented during the meeting...

... As a summary I present a probable model for the evolution of the nearby starburst galaxies by taking into account observations of their large-scale and nuclear gas dynamics as well as numerical simulations of gas flows in galaxies. ... Thus, it is very likely that galaxy interaction plays an important role in the formation of bars . ... A good example is the barred starburst galaxy NGC 1808. ... In fact, one can nearly see the gas flowing toward the galaxy centre where it fuels the nuclear starburst...