|
Collection:
|
|
NASA Astronomy Picture of the Day Collection
Collection
NASA Astronomy Picture of the Day Collection
Collection
|
|
Title:
|
|
HR 4796A: Not Saturn
Title
HR 4796A: Not Saturn
Title
|
|
Explanation:
|
These are not false-color renderings of the latest observations of Saturn's magnificent rings [ http://antwrp.gsfc.…]. 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.stsc…], 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.a…], 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.generati…] around HR 4796A. The top panels show the false-color images [ http://nicmosis.as.…] at two infrared wavelengths from the Hubble Space Telescope's NICMOS instrument [ http://nicmos.as.ar…], 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.
Explanation
These are not false-color renderings of the latest observations of Saturn's magnificent rings [ http://antwrp.gsfc.…]. 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.stsc…], 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.a…], 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.generati…] around HR 4796A. The top panels show the false-color images [ http://nicmosis.as.…] at two infrared wavelengths from the Hubble Space Telescope's NICMOS instrument [ http://nicmos.as.ar…], 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. Explanation
|
|
Credit and Copyright:
|
Credit_and_Copyright
Credit and Copyright
|
|
keyword:
|
|
dust
|
|
keyword:
|
|
planets
|
|
keyword:
|
|
ring
|
|
facet_where:
|
|
Arizona
facet_where
Arizona
facet_where
|
|
facet_where:
|
|
Saturn
facet_where
Saturn
facet_where
|
|
facet_where:
|
|
Hawaii
facet_where
Hawaii
facet_where
|
|
facet_where:
|
|
Goddard Space Flight Center (GSFC)
facet_where
Goddard Space Flight Center (GSFC)
facet_where
|
|
facet_what:
|
|
Earth
facet_what
Earth
facet_what
|
|
facet_what:
|
|
Sun
facet_what
Sun
facet_what
|
|
facet_what:
|
|
Saturn
facet_what
Saturn
facet_what
|
|
facet_what:
|
|
Neptune
facet_what
Neptune
facet_what
|
|
facet_what:
|
|
NICMOS
facet_what
NICMOS
facet_what
|
|
facet_what:
|
|
TRACE
facet_what
TRACE
facet_what
|
|
facet_what:
|
|
VEGA
facet_what
VEGA
facet_what
|
|
facet_what:
|
|
Hubble Space Telescope (HST)
facet_what
Hubble Space Telescope (HST)
facet_what
|
|
original url:
|
original_url
original url
|
|
UID:
|
|
SPD-APOD-ap990205
UID
SPD-APOD-ap990205
UID
|
