每日星挑战 每日星相:Daily Astronomy(6)

每日星相:Daily Astronomy(6)  

Nix and Hydra were first introduced to human eyes in Hubble Space Telescope images from May 2005
as Pluto's second and third known moons. Now Hubble images have revealed a fourth satellite for the icy
dwarf pla. Provisionally designated P4
it pletes an orbit of Pluto in about 31 days. Presently Pluto's smallest and dimmest known moon
P4 is estimated to be 13 to 34 kilometers across. The newly discovered satellite was first spotted in Hubble observations from June 28
and later confirmed in a follow-up on July 3 and July 18. These o panelsare posites of both the short and long exposures that include brighter Pluto itself along with Pluto's largest moon Charon. Camera noise and image artifacts also show up in the long exposure segments. The Hubble observations were made while searching for faintrings around the distant world in support of NASA's New Horizons mission
set to fly by the Pluto system in 2015.

重点注释：
panel专家小组
exposure公开，透露，泄露，揭示
segment部分
份
片
段
faint微弱的
模糊的
暗淡的