21 July 2013
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Neptune, the blue giant planet
Credit: NASA-JPL
NASA's Hubble Space Telescope (HST) has discovered a new moon orbiting the most distant planet, Neptune. The blue giant planet now has 14 known satellites.
The new Neptunian moon, known as S/2004 N 1, is estimated to be less than 20 km across, making it the smallest of Neptune’s satellites. It is so small and faint that it is about 100 million times dimmer than the faintest star that can be seen with the unaided eye. It even escaped detection by NASA's Voyager 2 spacecraft, which visited Neptune in 1989, and explored the planet's system of moons and rings.
S/2004 N 1 was discovered on 1 July, by astronomer Mark Showalter, of the SETI Institute, while studying the rings of Neptune. It was spotted by scanning over 150 images of HST, taken from 2004 to 2009.
Showalter plotted a circular orbit for S/2004 N 1, which completes one revolution around Neptune every 23 hours. For comparison, the Moon orbits Earth every 27.3 days.
Further Reading
http://hubblesite.org/news/2013/30
www.nasa.gov/
www.nasa.gov/hubble
Aymen Mohamed Ibrahem
Senior Astronomy Specialist