On the California mountain from which Edwin Hubble discovered that the universe was expanding, astronomers have achieved first light with a new infrared camera and made some nifty discoveries in the process.
Using the 100-inch telescope at the Mount Wilson Observatory near Pasadena, the astronomers found three previously undetected faint stars, each orbiting larger and brighter companion stars.
"This is the first time the historic Mount Wilson telescope has looked at the universe through this new infrared eye, and already it is making new discoveries," said Jian Ge, assistant professor of astronomy and astrophysics at Penn State and leader of team that developed the camera and made the discoveries.
The results do not represent a major scientific finding -- similar dim stars have been discovered from other observatories. But they "mark the beginning of a new era in the use of the 100-inch telescope for discovering very interesting faint objects in orbit around brighter stars, such as brown dwarfs, which are neither stars nor planets," said Robert Jastrow, director of the Mount Wilson Institute.
The findings will be published in the June issue of Astrophysical Journal Letters and the July issue of the Astronomical Journal.
The infrared camera, which detects electromagnetic radiation in the form of heat rather than visible light, has a specially shaped mask that covers the "pupil" of the camera's eye to allow fainter companions to be seen around bright objects.
"The image resulting from the first use of the device revealed areas of greater contrast that allowed us to find one of the faint dwarf stars," Ge said. "The technique potentially improves contrast in images by more than tenfold compared to current techniques." (Other telescopes are equipped with similar coronagraphs, as they are called.)
Future space-based telescopes will likely draw from this technology to image Earth-like planets around other stars, said David Spergel, Princeton University researcher who recommended the new approach to Ge. "Jian's work at Mount Wilson is a pathfinder for the Terrestrial Planet Finder being planned by NASA."
The dwarf stars are less than one-tenth the mass of the Sun and give off a dark-red glow that is dimmer than our hotter Sun's yellow light. One of the stars is about 50 light years from Earth, another is about 27 light years away, and the third is at a distance of about 200 light years.
Astronomers consider these stars to be nearby in our solar system's corner of the galaxy.
"Our initial conservative estimate is that these are little very-dark-red dwarf stars," says Abhijit Chakraborty, a postdoctoral scholar on Ge's team. "Their mass is only about 80 to 100 times that of Jupiter, which itself is a thousand times smaller than our Sun. They have barely enough mass to burn the hydrogen in their cores, and are close to the size and luminosity of less-massive brown-dwarf objects, which don't have enough mass to ignite into stars at all."
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