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Keck Observatory of Goddard Space Flight Center (GSFC)
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Deep Field, X-ray/Optical
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Deep Field, X-ray/Optical |
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Eris: The Largest Known Dwar
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| Title |
Eris: The Largest Known Dwarf Planet |
| Explanation |
Is Pluto the largest dwarf planet? No! Currently, the largest known dwarf planet is (136199) Eris [ http://en.wikipedia.org/wiki/136199_Eris ], renamed last week from 2003 UB313 [ http://antwrp.gsfc.nasa.gov/apod/ap060207.html ]. Eris is just slightly larger than Pluto, but orbits as far as twice Pluto [ http://antwrp.gsfc.nasa.gov/apod/ap060903.html ]'s distance from the Sun. Eris is shown above [ http://www.keckobservatory.org/view_album.php?album_id=4 ] in an image taken by a 10-meter Keck Telescope [ http://antwrp.gsfc.nasa.gov/apod/ap971227.html ] from Hawaii [ http://antwrp.gsfc.nasa.gov/apod/ap951216.html ], USA [ https://www.cia.gov/cia/publications/factbook/geos/us.html ]. Like Pluto, Eris has a moon, which has been officially named [ http://cfa-www.harvard.edu/iau/special/08747.pdf ] by the International Astronomical Union [ http://www.iau.org/ ] as (136199) Eris I (Dysnomia). Dysnomia [ http://en.wikipedia.org/wiki/Dysnomia_%28moon%29 ] is visible above just to the right of Eris. Dwarf planets [ http://en.wikipedia.org/wiki/Dwarf_planet ] Pluto and Eris are trans-Neptunian objects [ http://www.planetary.org/explore/topics/trans_neptunian_objects/ ] that orbit in the Kuiper belt [ http://www.ifa.hawaii.edu/~jewitt/kb.html ] of objects past Neptune. Eris [ http://antwrp.gsfc.nasa.gov/apod/ap050801.html ] was discovered in 2003, and is likely composed of frozen water-ice and methane [ http://en.wikipedia.org/wiki/Methane ]. Since Pluto's recent demotion by the IAU [ http://en.wikipedia.org/wiki/International_Astronomical_Union ] from planet to dwarf planet status, Pluto [ http://voyagesolarsystem.org/gallery/gallery_10.html ] has recently also been given a new numeric designation: (134340) Pluto. Currently, the only other officially designated "dwarf planet" is (1) Ceres [ http://antwrp.gsfc.nasa.gov/apod/ap060821.html ]. |
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Double Asteroid 90 Antiope
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Double Asteroid 90 Antiope |
| Explanation |
This eight-frame animation is based on the first ever images [ http://www.boulder.swri.edu/~merline/press/ ] of a double asteroid [ http://www.boulder.swri.edu/~merline/press/release.txt ]! Formerly thought to be a single enormous chunk of rock, asteroid 90 Antiope [ http://cfa-www.harvard.edu/iau/lists/ NumberedMPs00001.html ] resides in the solar system's [ http://space.jpl.nasa.gov/ ] main asteroid belt [ http://seds.lpl.arizona.edu/nineplanets/nineplanets/ asteroids.html ] between Mars and Jupiter. Now, these premier images reveal Antiope to actually consist of two 50 mile wide asteroids separated by about 100 miles. Like weights on each end of an elastic string, the pair mutually orbit [ http://hyperphysics.phy-astr.gsu.edu/hbase/ orbv.html#bo ] their center of mass, or balance point in the space between them, once every 16.5 hours. Binary asteroids and asteroids with moons [ http://antwrp.gsfc.nasa.gov/apod/ap991014.html ] are believed to be rare, but observations of their orbits allow a direct determination of asteroid masses and densities. Surprisingly, Antiope and known [ http://www.cfht.hawaii.edu/News/PR_001026/ ] asteroid-moon [ http://antwrp.gsfc.nasa.gov/apod/ap990807.html ] systems are found to have densities closer to ice than rock, despite their relatively dark and unreflective surfaces. These sharp images were made at the Keck Observatory atop the Hawaiian volcano Mauna Kea using newly developed adaptive optics [ http://www.mtwilson.edu/Science/ AdapOpt/Overview/ ] technology to overcome the blurring effect [ http://antwrp.gsfc.nasa.gov/apod/ap000725.html ] of Earth's atmosphere. |
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LkHa101: The Hole in the Dou
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LkHa101: The Hole in the Doughnut |
| Explanation |
You'd need a really big cup of coffee with this doughnut [ http://www.physics.usyd.edu.au/~gekko/ doughnut.html ] ... because the hole in the middle is about a billion kilometers across. Centered on the Sun, a circle that size would lie between the orbits of Mars and Jupiter. In fact, this doughnut is known to surround a massive newborn star cataloged as LkHa 101 which lies in the constellation Perseus [ http://www.allthesky.com/constellations/perseus/ constell.html ]. Imaged in infrared light [ http://cfa-www.harvard.edu/newtop/whatsnew.html ], the tantalizing torus-shaped cloud of gas and dust [ http://stardust.wustl.edu/IDPIntro.html ] is slightly tilted to our view. The cloud's material may well be the ingredients for the formation of a distant solar system [ http://www.spaceart.org/lcook/extrasol.html ]. A bright source of ultraviolet light [ http://imagine.gsfc.nasa.gov/docs/science/know_l1/ multiwavelength.html ], the hot young star itself is much fainter in the infrared and so not visible in this picture. Still, the star's presence is indicated as its intense stellar wind and radiation has apparently carved out the doughnut's hole. This premier close-up of a stellar system in formation was accomplished by adapting a powerful observational technique called interferometry [ http://www.sciam.com/2001/0301issue/0301armstrong.html ] to planet Earth's largest single mirror telescope, the 10 meter Keck [ http://www2.keck.hawaii.edu:3636/ ]. |
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A Year of Dark Cosmology
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A Year of Dark Cosmology |
| Explanation |
We live in the exciting time when humanity discovers the nature [ http://antwrp.gsfc.nasa.gov/debate/debate98.html ] of our entire universe. During this year, in particular, however, the quest for cosmological understanding appears to have astronomers groping in the dark. Dark matter [ http://www.sciam.com/specialissues/0398cosmos/0398rubin.html ] and dark energy [ http://www.lbl.gov/Science-Articles/Archive/dark-energy.html ] are becoming accepted invisible components of our universe, much like oxygen [ http://pearl1.lanl.gov/periodic/elements/8.html ] and nitrogen [ http://pearl1.lanl.gov/periodic/elements/7.html ] have become established invisible components of Earth-bound air [ http://www.dep.state.pa.us/earthdaycentral/97/air_teachers/naturally.htm ]. In comprehending [ http://antwrp.gsfc.nasa.gov/htmltest/gifcity/bitsff.html ] the nature and origin of the formerly invisible, however, we are only just exiting the cosmological dark age [ http://library.thinkquest.org/2834/gather/darkage/darkage.htm ]. Relatively unexplored concepts such as higher spatial dimensions [ http://antwrp.gsfc.nasa.gov/apod/ap010418.html ], string theories [ http://superstringtheory.com/ ] of fundamental particles [ http://particleadventure.org/ ], quintessence [ http://physicsweb.org/article/world/13/11/8/1 ], and new forms of inflation [ http://www.astro.ucla.edu/~wright/cosmo_04.htm ] all vie for cornerstone roles in a more complete theory [ http://www.sciam.com/2001/0101issue/0101peebles.html ]. As understanding invisible air has led to such useful inventions as the airplane [ http://www.wam.umd.edu/~stwright/WrBr/taleplane.html ] and the oxygen mask [ http://www.avweb.com/articles/howoxy.html ], perhaps understanding dark matter [ http://chandra.harvard.edu/xray_astro/dark_matter.html ] and dark energy [ http://xxx.lanl.gov/abs/astro-ph/9811454 ] can lead to even more spectacular and useful inventions. Pictured above [ http://www2.keck.hawaii.edu:3636/realpublic/gen_info/kiosk/gallery.html ], three of the largest optical telescopes [ http://www.seds.org/billa/bigeyes.html ] (Keck I, Keck II [ http://www2.keck.hawaii.edu:3636/realpublic/gen_info/kiosk/index.html ], and Subaru [ http://www.naoj.org/ ]) prepare to peer into the dark and distant universe. |
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GRB 980703: A Reassuring Red
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GRB 980703: A Reassuring Redshift |
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In the old days, just over a year ago, astronomers had little idea of the true distance to gamma-ray bursts [ http://antwrp.gsfc.nasa.gov/apod/ap961123.html ]. Did these enigmatic explosions [ http://www.sciam.com/0797issue/0797fishman.html ] occur in our outer Galaxy [ http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1995PASP%2E%2E107%2E1152L ], or in the outer Universe [ http://adsbit.harvard.edu/cgi-bin/nph-iarticle_query?1995PASP%2E%2E107%2E1167P ]? Last May, a first telling distance measure was made - GRB 970508 [ http://antwrp.gsfc.nasa.gov/apod/ap970513.html ] showed an absorption line [ http://antwrp.gsfc.nasa.gov/apod/ap980713.html http://www.bc.kern.cc.ca.us/programs/sea/Astronomy/light/lightb.htm#A2.2 ] with a redshift [ http://antwrp.gsfc.nasa.gov/apod/lib/glossary.html#redshift ] of about 0.8 - indicating that this gamma-ray burst [ http://science.msfc.nasa.gov/newhome/headlines/ast19sep97_2.htm ] (GRB) was an enormous distance away. Skeptics [ http://www.sff.net/people/MBourne/W-Skeptic.htp ], however, are not always convinced by an unrepeated measurement. Since then, though, other tantalizing coincidences have occurred: GRB 971214 [ http://antwrp.gsfc.nasa.gov/apod/ap980507.html ] occurred unusually near a galaxy with the enormous redshift of 3.4, and GRB 980425 [ http://antwrp.gsfc.nasa.gov/apod/ap980508.html ] occurred unusually near a peculiar low-redshift supernova [ http://legacy.gsfc.nasa.gov/docs/snr.html ]. Skeptics [ http://www.athenet.net/~jlindsay/SkepticQuotes.html ] were intrigued. Now, the potentially definitive implications of the above-pictured [ http://astro.caltech.edu/%7Egeorge/grb/grb980703.html ] optical transient might impress even the cautious. GRB 980703 [ http://gcn.gsfc.nasa.gov/gcn/gcn3/139.gcn3 ]'s optical transient shows a well-measured redshift from both an absorption line " and " an emission line [ http://astro.gmu.edu/classes/a10695/notes/l03/l03s028.html ]: 0.97. The above negative highlights the uncommon transient source with the label "OT", while letters designate common comparison stars [ http://gcn.gsfc.nasa.gov/gcn/gcn3/144.gcn3 ]. |
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A Sharper View of a Tilted P
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A Sharper View of a Tilted Planet |
| Explanation |
These sharp views [ http://www2.keck.hawaii.edu/news/science/uranus/ index.html ] of tilted gas giant Uranus [ http://www.nineplanets.org/uranus.html ] show dramatic details of the planet's atmosphere and ring system [ http://ringmaster.arc.nasa.gov/uranus/uranus.html ]. The remarkable ground-based images [ http://www.news.wisc.edu/10402.html ] were made using a near-infrared camera and the Keck Adaptive Optics system to reduce the blurring effects of Earth's atmosphere. Recorded in July, the pictures show [ http://www.news.wisc.edu/newsphotos/ uranus2.html ] two sides of Uranus (careful how you pronounce [ http://www.nineplanets.org/say/uranus.au ] that ...). In both, high, white cloud features are seen mostly in the northern (right hand) hemisphere, with medium level cloud bands in green and lower level clouds in blue. The artificial color scheme lends a deep reddish tint to the otherwise faint rings [ http://antwrp.gsfc.nasa.gov/apod/ap030115.html ]. Because of the severe tilt of its rotational axis, seasons on Uranus [ http://www.haydenplanetarium.org/hp/vo/ava/avapages/ P0418uranseas.html ] are extreme and last nearly 21 Earth years on the distant planet [ http://nssdc.gsfc.nasa.gov/ planetary/factsheet/uranusfact.html ]. Uranus is now slowly approaching its southern autumnal equinox - the beginning of fall in the southern hemisphere - in 2007. |
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Red Saturn
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Red Saturn |
| Explanation |
This strange, false-color image [ http://www2.keck.hawaii.edu/news/science/ saturn/ ] of otherwise familiar planet Saturn [ http://nssdc.gsfc.nasa.gov/planetary/factsheet/ saturnfact.html ] shows temperature changes based on thermal infrared [ http://coolcosmos.ipac.caltech.edu/ ] emission in the gas giant's atmosphere [ http://www.windows.ucar.edu/tour/link=/saturn/ lower_atmosphere.html&edu=high ] and rings. Recorded from the Keck I telescope on Mauna Kea [ http://www.ifa.hawaii.edu/mko/ ], the sharp, ground-based picture of Saturn's southern hemisphere is a mosaic of 35 images. Based on the effects [ http://antwrp.gsfc.nasa.gov/apod/ap040626.html ] of sunlight during the southern summer season [ http://antwrp.gsfc.nasa.gov/apod/ap030405.html ], general warming trends were anticipated. But a surprising result of the infrared image data is the a clear indication of an abruptly warmer polar cap and bright hot spot at Saturn's south pole. The warm south pole and hot spot may be unique in the solar system [ http://solarsystem.nasa.gov/index.cfm ] and a further exploration of the region is planned using instruments [ http://cirs.gsfc.nasa.gov/ ] on the Cassini spacecraft. So how hot is Saturn's hot spot? The upper tropospheric temperature is a sweltering 91 Kelvin [ http://my.unidata.ucar.edu/content/staff/blynds/ tmp.html ] (-296 degrees Fahrenheit) at the pole. |
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WR 104: Pinwheel Star
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WR 104: Pinwheel Star |
| Explanation |
Like a cosmic lawn sprinkler, dust streaming from a rotating star system creates a pinwheel pattern in this false color infrared image [ http://isi.ssl.berkeley.edu/wr104.html ]. Astronomers discovered the surprising star dust scenario using a sophisticated interferometer [ http://isi.ssl.berkeley.edu/isi.html ] and the 10 meter Keck I telescope to observe the bright Wolf-Rayet star WR 104. Wolf-Rayet stars [ http://www.star.ucl.ac.uk/~hsn/ ] are thought to be massive objects on the brink of a cataclysmic supernova explosion - having grown so hot [ http://www.star.ucl.ac.uk/~idh/home.html ] and bright that their intense light begins [ http://www.limber.org/sts98/rad.html ] to drive material away in a stellar wind. The problem is, their starlight would also be so intense that any dust flakes [ http://www.pha.jhu.edu/~danforth/superfit/superfit.html ] should be destroyed! A possible solution to this [ http://isi.ssl.berkeley.edu/nature.ps ] dusty dilemma is that a companion star exists hidden in the bright central region, generating wind interactions which shield a relatively narrow dust forming region from the light of WR 104. As the binary system rotates [ http://astrosun.tn.cornell.edu/courses/astro201/kepler_binary.htm ], the spray of surviving dust particles appears to spiral outward. |
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