Narrow Search
 
 
Advanced Search

Browse All : VEGA and Sun of Goddard Space Flight Center (GSFC)

Printer Friendly
1-2 of 2
     
     
Vega Credit: D. Moffatt (DOA …
Title Vega Credit: D. Moffatt (DOA [ http://www.dao.nrc.ca/ ]), ScienceWeb [ http://scienceweb.dao.nrc.ca/ ], Starry Messenger Communications
Explanation Vega is a bright blue star 25 light years away. Vega [ http://stardate.utexas.edu/radio/StarDateDB.FM$RETRIEVE?value=06/15/1996&field=ScriptAirDate&html=Test+Request+Date ] is the brightest star in the Summer Triangle [ http://eagle.online.discovery.com/DCO/doc/1012/world/starshack/starshack080796/starshack.html ], a group of stars easily visible summer evenings in the northern hemisphere. The name Vega [ http://www.astro.wisc.edu/~dolan/constellations/hr/7001.html ] derives from Arabic origins, and means "stone eagle." 4,000 years ago, however, Vega [ http://stardate.utexas.edu/radio/StarDateDB.FM$RETRIEVE?value=05/20/1995&field=ScriptAirDate&html=Test+Request+Date ] was known by some as "Ma'at" - one example of ancient human astronomical knowledge and language. 14,000 years ago, Vega [ http://stardate.utexas.edu/radio/StarDateDB.FM$RETRIEVE?value=07/10/1994&field=ScriptAirDate&html=Test+Request+Date ], not Polaris [ http://www.arcorp.com/polaris.html ], was the north star [ http://antwrp.gsfc.nasa.gov/apod/ap961201.html ]. Vega [ http://adsabs.harvard.edu/cgi-bin/nph-bib_query?1995ApJ%2E%2E%2E450%2E%2E364G&db_key=AST&nosetcookie=1 ] is the fifth brightest star in the night sky, and has a diameter almost three times that of our Sun. Life [ http://www.seti-inst.edu/phoenix/contact.html ] bearing planets, rich in liquid water, could possibly exist around Vega [ http://lsnt7.lightspeed.net/~astronomy/lifezones/lifezones.html ]. The above picture [ http://www.jpl.nasa.gov/comet/moffatt1.html ], taken in January, finds Vega, the Summer Triangle [ http://antwrp.gsfc.nasa.gov/apod/ap961212.html ], and Comet Hale-Bopp [ http://antwrp.gsfc.nasa.gov/apod/ap970610.html ] high above Victoria [ http://www.city.victoria.bc.ca/ ], British Columbia [ http://www.gov.bc.ca/ ], Canada.
HR 4796A: Not Saturn
Title HR 4796A: Not Saturn
Explanation These are not false-color renderings of the latest observations of Saturn's magnificent rings [ http://antwrp.gsfc.nasa.gov/apod/ap980424.html ]. Instead, the panels show a strikingly similar system on a much larger scale - a ring around the young, Vega-like star, HR 4796A [ http://oposite.stsci.edu/pubinfo/pr/1999/03/b.html ], located about 200 light-years from Earth. Probably composed of dusty debris ground from colliding planetesimals, this ring is confined to a zone less than 17 AU wide (1 AU equals the Earth-Sun distance) and girdles the star at a radius of about 70 AU, roughly twice the orbital radius of Neptune. In analogy with the relationship of Saturn's rings and moons [ http://ringmaster.arc.nasa.gov/reference/abstracts/cuzzi1984_01.html ], this circumstellar ring could be held in place by forces due to planets - shepherding planetary bodies or the gravitational influence of larger planets orbiting closer to the parent star. In any event, because the ring would not survive long without something to keep it there, astronomers consider its presence strong evidence for unseen planetary bodies [ http://www.generation.net/~mariob/astro/xtrasol.htm ] around HR 4796A. The top panels show the false-color images [ http://nicmosis.as.arizona.edu:8000/AAS99/hr4796_postrev5.ps ] at two infrared wavelengths from the Hubble Space Telescope's NICMOS instrument [ http://nicmos.as.arizona.edu/ ], and the bottom panels trace the corresponding image contours. At the center of each, the overwhelming light of HR 4796A has been masked to reveal the fainter circumstellar ring.
1-2 of 2