Phoebe is the outermost of Saturn's known satellites. Phoebe is almost 4 times more distant from Saturn than its nearest neighbor (Iapetus).
orbit: 12,952,000 km from Saturn
diameter: 220 km
mass: 4.0e18 kg
Phoebe is the daughter of Uranus and Gaia; grandmother of Apollo and Artemis.
Discovered by Pickering in 1898.
On June 11, 2004 Cassini passed close to Phoebe on its way into the Saturn system, giving us our first real look at it since Voyager and at much higher resolution.
Most of Saturn's moons are bright but Phoebe's albedo is very low (.05), as dark as lampblack.
All of Saturn's moons except for Phoebe and Iapetus orbit very nearly in the plane of Saturn's equator. Phoebe's orbit is inclined almost 175° (its north pole is in the opposite direction to Saturn's).
Phoebe's eccentric, retrograde orbit and unusual albedo indicates that it may be a captured comet or Kuiper Belt object. Data from Cassini's 2004 flyby reinforces this idea with the detection of CO2 trapped within its rocks. This rules out the earlier idea that it might have been a captured asteroid. It appears that Phoebe is chemically similar to Pluto and Triton. It is probably very similar to the chemical composition of the outer solar system at the very beginning.
Phoebe is also unusual in that it does not rotate synchronously as do all the other moons of Saturn except Hyperion.
Material knocked off of Phoebe's surface by microscopic meteor impacts may be responsible for the dark surfaces of Hyperion and the leading hemisphere of Iapetus.
Phoebe 是土星已知衛(wèi)星中最外層一顆，幾乎是其近鄰衛(wèi)星（土衛(wèi)八）到土星距離的4倍。
公轉(zhuǎn)軌道：距土星 12,952,000 千米
衛(wèi)星直徑：220 千米
質(zhì)量：4.0e18 千克
福柏(Artemis)是狩獵與月亮女神，阿波羅的同胞妹妹。
它由Pickering于1898年發(fā)現(xiàn)。
大多數(shù)土星的衛(wèi)星是明亮的，但是土衛(wèi)九的反照率只有0.05，像煤煙一樣暗。
除了土衛(wèi)九與土衛(wèi)八，所有的土星衛(wèi)星公轉(zhuǎn)面與土星赤道面一致。土衛(wèi)九公轉(zhuǎn)傾斜角近175度（它的北極與土星的正相反）。
土衛(wèi)九的偏心的，逆向的公轉(zhuǎn)軌道和不尋常的反照率說明它可能是一顆被捕捉的小行星或是Kuiper帶中的物體。
土衛(wèi)九的不尋常還表現(xiàn)在自轉(zhuǎn)非同步，與其他土星衛(wèi)星除土衛(wèi)七外不同。
由于細微的流星體撞擊，土衛(wèi)九上掉落的物質(zhì)可能與土衛(wèi)七表面和土衛(wèi)八逆公轉(zhuǎn)半球的黑暗有關(guān)。
orbit: 12,952,000 km from Saturn
diameter: 220 km
mass: 4.0e18 kg
Phoebe is the daughter of Uranus and Gaia; grandmother of Apollo and Artemis.
Discovered by Pickering in 1898.
On June 11, 2004 Cassini passed close to Phoebe on its way into the Saturn system, giving us our first real look at it since Voyager and at much higher resolution.
Most of Saturn's moons are bright but Phoebe's albedo is very low (.05), as dark as lampblack.
All of Saturn's moons except for Phoebe and Iapetus orbit very nearly in the plane of Saturn's equator. Phoebe's orbit is inclined almost 175° (its north pole is in the opposite direction to Saturn's).
Phoebe's eccentric, retrograde orbit and unusual albedo indicates that it may be a captured comet or Kuiper Belt object. Data from Cassini's 2004 flyby reinforces this idea with the detection of CO2 trapped within its rocks. This rules out the earlier idea that it might have been a captured asteroid. It appears that Phoebe is chemically similar to Pluto and Triton. It is probably very similar to the chemical composition of the outer solar system at the very beginning.
Phoebe is also unusual in that it does not rotate synchronously as do all the other moons of Saturn except Hyperion.
Material knocked off of Phoebe's surface by microscopic meteor impacts may be responsible for the dark surfaces of Hyperion and the leading hemisphere of Iapetus.
Phoebe 是土星已知衛(wèi)星中最外層一顆，幾乎是其近鄰衛(wèi)星（土衛(wèi)八）到土星距離的4倍。
公轉(zhuǎn)軌道：距土星 12,952,000 千米
衛(wèi)星直徑：220 千米
質(zhì)量：4.0e18 千克
福柏(Artemis)是狩獵與月亮女神，阿波羅的同胞妹妹。
它由Pickering于1898年發(fā)現(xiàn)。
大多數(shù)土星的衛(wèi)星是明亮的，但是土衛(wèi)九的反照率只有0.05，像煤煙一樣暗。
除了土衛(wèi)九與土衛(wèi)八，所有的土星衛(wèi)星公轉(zhuǎn)面與土星赤道面一致。土衛(wèi)九公轉(zhuǎn)傾斜角近175度（它的北極與土星的正相反）。
土衛(wèi)九的偏心的，逆向的公轉(zhuǎn)軌道和不尋常的反照率說明它可能是一顆被捕捉的小行星或是Kuiper帶中的物體。
土衛(wèi)九的不尋常還表現(xiàn)在自轉(zhuǎn)非同步，與其他土星衛(wèi)星除土衛(wèi)七外不同。
由于細微的流星體撞擊，土衛(wèi)九上掉落的物質(zhì)可能與土衛(wèi)七表面和土衛(wèi)八逆公轉(zhuǎn)半球的黑暗有關(guān)。