By ERIN MILLER
Stephens Media
Gemini’s North telescope played a role in refining information about former planet Pluto and its companion Charon.
In the process, astronomers continued to improve their abilities to identify Earth-sized objects, Gemini spokesman Peter Michaud said.
“We’re refining our ability to detect smaller and smaller objects,” Michaud said. “That’s exciting.”
Steve Howell of the NASA Ames Research Center and his team temporarily installed a Differential Speckle Survey Instrument on the Gemini telescope on Mauna Kea. The team focused the instrument on Pluto and Charon and took a series of images, which were then used to get the clearest picture yet of the pair taken from Earth.
Michaud said the speckle process takes images quickly, then combines them in a way that removes visual “noise” from each shot, by removing items that moved from place to place when the images were compared. The noise, which look like speckles in the image, comes from distortion created by looking at distant objects through Earth’s atmosphere.
Once the speckles are removed, the remaining, combined images show the objects as they appear without the distortion, Michaud said.
NASA’s Kepler mission will benefit from the technique, Howell said. Another NASA mission, the New Horizons spacecraft, will use information taken from images about the refined measurements of Pluto’s and Charon’s diameters and orbital dynamics.
“The Pluto-Charon result is of timely interest to those of us wanting to understand the orbital dynamics of this pair for the 2015 encounter by NASA’s New Horizons spacecraft,” Howell said.
Scientists said Kepler identifies items that could be planets by repeatedly measuring the change in brightness of more than 150,000 stars. When an item passes in front of the star, for example, that can affect the brightness of the star.
“Speckle imaging with the Gemini telescope will provide Kepler’s follow-up program with a doubling in its ability to resolve objects and validate Earth-like planets,” Gemini officials said. “It also offers a 3- to 4-magnitude sensitivity increase for the sources observed by the team. That’s about a 50-fold increase in sensitivity in the observations Howell and his team made at Gemini.”
Howell said the improvements brought an “enormous gain” for scientists looking for Earth-sized objects.
The National Science Foundation and NASA’s Kepler discovery mission partially funded the research. It will be published in the journal Publications of the Astronomical Society of the Pacific in October.
Email Erin Miller at
emiller@westhawaiitoday.com.
