starship-design: Backyard Astronomy: Study Uncovers 12 Nearby Stars

["L. Clayton Parker" <lparker@cacaphony.net>]

Backyard Astronomy: Study Uncovers 12 Nearby Stars
By Robert Roy Britt
Senior Science Writer
posted: 11:30 am ET
11 January 2002



WASHINGTON D.C. - With astronomers finding galaxies that are billions of
light-years away and spotting stars thousands of light-years distant in our
own galaxy, you'd think they'd know about all the stars in our backyard.

Not so. Today, researchers announced a dozen newly found stars all within 33
light-years of Earth -- next-door neighbors by cosmic measures. All the
stars were found in the southern sky, where surveys are less comprehensive
than from the Northern Hemisphere.

The discoveries were made by a team of researchers led by Todd Henry of
Georgia State University. Henry and his colleagues are working to build a
3-D map of the local sky.

The nearest known star is Proxima Centauri, which is 4.2 light-years away.
The nearest of the newly discovered objects is 20 light-years away, putting
it at 55th on the list of closest stars.

The stars come in three configurations: Seven are alone in space; two orbit
each other in what's called a binary star system; and the remaining three
are in a rarer three-star system, all orbiting each other.

All had gone unseen because they are thousands of times fainter than stars
that can be seen with the naked eye. The nearest one is only about a third
of the size of the Sun and emits less than 1 percent as much light.

One of the stars is a white dwarf. The others are red dwarfs.

Red dwarfs are sometimes counted as part of "dark matter," somewhat
mysterious material that can't be seen but that researchers know must exist
based on the amount of gravity at work in galaxies.

White dwarf stars are typically about the size of Earth, but they can be as
massive as the Sun. That makes them dense. A teaspoonful of a white dwarf
weighs as much as an elephant. White dwarf stars are the end of the
evolutionary road for smallish stars, ones that could not generate the
spectacular explosions that mark the death of larger stars.

Because of their proximity, the newly identified stars could prove useful as
targets for planet hunters.

"Each of the new stars provides a fresh target where we can look for
planets, and ultimately, for life on those planets," Henry said here at a
meeting of the American Astronomical Society.

The stars were studied with two telescopes at the Cerro Tololo Interamerican
Observatory in Chile. The research team included Georgia State's Wei-Chun
Jao and John Subasavage; Phil Ianna of the University of Virginia; Rene
Mendes of the European Southern Observatory; and Edgardo Costa of the
Universidad de Chile.