Hubble Space Telescope Discovers Pluto’s Fourth Moon
http://www.dearastronomer.com/
Illustration of the Pluto Satellite System orbits with newly discovered moon P4 highlighted. Image Credit: NASA, ESA, and A. Feild (STScI)
Still doesn’t make Pluto a planet, but astronomers using the Hubble Space Telescope recently discovered a fourth moon orbiting dwarf planet Pluto. Temporarily designated “P4″, the object was discovered during a survey looking for rings around Pluto.
The current estimate for P4′s size is a diameter of 8 to 21 miles. Compared to Pluto’s binary companion, Charon, at 648 miles (1,043 km) across, P4 is closer to the size of Nix and Hydra (20 to 70 miles in diameter). P4 is located between the orbits of Nix and Hydra, which were discovered by the HST in 2005. Charon was discovered in 1978 at the U.S. Naval Observatory.
In a NASA press release, Mark Showalter of the SETI Institute said: “I find it remarkable that Hubble’s cameras enabled us to see such a tiny object so clearly from a distance of more than 3 billion miles“.
The study of Pluto is part the research being performed in order to prepare for NASA’s New Horizons mission, which is scheduled in 2015 to perform a fly-by of the Pluto system. The New Horizons mission’s goal is to provide additional knowledge about the worlds at the edge of our solar system. The data collected on Pluto by the HST is proving to be a valuable asset for the planning stages of New Horizons’ close encounter.
Alan Stern, New Horizons’ principal investigator adds “Now that we know there’s another moon in the Pluto system, we can plan close-up observations of it during our flyby.“
The image showing P4 below was taken with Hubble’s Wide Field Camera 3 on June 28. The discovery was confirmed with additional images taken on July 3rd and 18th. There are claims that P4 may have appeared in images from 2006, but was overlooked due to obscuration.
For additional images and more information about Hubble, visit: http://www.nasa.gov/hubble or http://hubblesite.org
Two labeled images of the Pluto system taken by the Hubble Space Telescope's Wide Field Camera 3 ultraviolet visible instrument with newly discovered fourth moon P4 circled. The image on the left was taken on June 28, 2011. The image of the right was taken on July 3, 2011 – Click to see a larger image showing the motion of “P4″. Credit: NASA, ESA, and M. Showalter (SETI institute)
Source:NASA/HST Mission Updates
Ray Sanders is a Sci-Fi geek, astronomer and blogger. Currently researching variable stars at Arizona State University, he writes for Universe Today, The Planetary Society blog, and his own blog, Dear Astronomer
2012-12-04 08:06:24
Source: http://www.dearastronomer.com/2011/07/20/hubble-space-telescope-discovers-plutos-fourth-moon/
Source:
