Starz in the Hood
There are more stars in our celestial backyard than we once thought.
- By Michael Milstein
- Air & Space magazine, May 2000
(Page 4 of 5)
Astronomers also don’t always share information as effectively as they could, so it may be that parallax data for other nearby stars actually will be found in Ianna’s or some other researcher’s files. Or it could be that different astronomers have pieces of the puzzle that, once put together, could reveal stars much closer than anyone thought. So Backman’s team will build an unprecedented database from as much information as they can round up from the existing scientific literature, and make it available to astronomers and the general public over the Internet. The team’s search for relevant information has already turned up other candidate nearby stars. An expected influx of additional data from new sky mapping projects such as the Sloan Digital Sky Survey—which aims to chart more than a hundred million celestial objects, including stars, galaxies, and quasars—should yield even more discoveries.
The second element of NStars calls for additional research—using telescopes around the world to identify “new” nearby stars based on their parallaxes and to learn more about those that are already known. University of Texas astronomer Fritz Benedict, for instance, plans to seek funding to examine about 500 stars for signs that they are binary, or double stars; he expects that around 20 percent will be. Researchers could then exclude those stars from the list of candidates for planet hunting, because stable planets are unlikely to form in binary systems.
The research will have a wider purpose than just adding to the roster of nearby stars, says Benedict. “It’s not only filling in the blanks on our star catalogs, but also filling in our understanding of the way solar systems might work.”
The idea of NStars had so much appeal that when NASA launched the project last year, the National Science Foundation quickly offered to contribute half the initial funding of $1.2 million. By October, the funding agencies had received around 80 proposals, twice as many as they had expected, which led them to try to scrounge up more money.
Backman and Henry sound like kids on Christmas Eve when they talk about the wonders NStars should soon reveal. “I’ve been waiting for this for 10 years,” beams Henry. “I’m sure we will find new things, all kinds of crazy things. The nearest star, Proxima Centauri, may not be the nearest star. It’s really hard to guess what we’re going to find.”
But he hazards a guess anyway. Henry figures that most of the 2,000 or so uncounted stars within 25 parsecs of us will turn out to be faint red dwarfs about the size of Jupiter. Stellar censuses suggest that these dim objects, which are far fainter than the sun, dominate the star population, and our own neighborhood should be no exception. Although such stars shine too feebly to offer much hope of finding planets suitable for life, Berkeley’s Debra Fischer and her planet-hunting colleagues have already found one planet revolving about a red dwarf. They believe that most red dwarfs—in fact most stars—sport planets of some type.
“I think they all have planets,” Fischer says. “The mounting evidence we have is basically that if we can find planets around a star—if our technology is good enough to see them—then we do. It really looks like planets are manufactured very efficiently around stars.”
There’s one last reason, of course, to tote up a list of nearby stars, and to find out if they have habitable planets. If we ever learn how to travel the immense distances of interstellar space, we’ll want to visit the closest solar systems first.