UH brown dwarf discovery challenges modern theories
Brown dwarf found near sun-like star, discovery
By Christine Cabalo
January 14, 2002
Astronomers may now have to rethink their theories about heavenly
A research team headed by University of Hawai'i at Manoa Beatrice
Parrent fellow Dr. Michael Liu has discovered a brown dwarf near a
star similar to our own sun.
The impact of the team's findings could have long lasting
repercussions on how scientists look at the stars, according to Liu.
The brown dwarf Liu's team discovered is much bigger than what
scientists would expect near a sun-like star that theorists will now
have to explain how such an occurrence is possible.
"This finding suggests that a diversity of processes act to
populate the outer regions of other solar systems," said Liu.
"The parent star is very similar to our sun, yet it has a brown
dwarf companion whose mass is dozens of times the combined mass of
all the planets in our solar system."
Brown dwarfs are objects categorized between stars and planets.
Astronomers sometimes call them "failed stars" because they are too
cold and small to initiate the nuclear reactions that are found in
normal bright stars.
Yet, brown dwarfs are far bigger than the size of planets. The
brown dwarf that was found by Liu and his associates is 55 to 78
times bigger than the planet Jupiter.
The estimated distance between the brown dwarf and the star is 14
Astronomical Units (AU), which is 14 times the distance between
Earth and the sun. A single AU is about 93 million miles.
Normally, much smaller objects, like planets, form at those
distances. The planet Saturn orbits the sun at 10 AU, and Uranus
orbits at 19 AU.
"It's the closest we've ever seen a brown dwarf next to a star,
but its odd because it's much larger than the planets we would
normally expect to form there," said UH Professor and former
director of the Mauna Kea observatories Bob Joseph.
The leading theory about the formation of our solar system
contends that our planets were formed from gas and dust in the area
near our sun when it was younger. The gas and dust collected formed
terrestrial planets like Earth and Mercury, as well as more gaseous
planets like Jupiter and Saturn.
Liu's research, presented at a recent press conference in
Washington, D.C., contends that the brown dwarf seems to have been
created from gas and dust leftover from its parent star, or the
large star next to it.
"Its unlikely that the brown dwarf was created by a collision.
Usually when those happen, objects tend to develop together. This
brown dwarf doesn't seem to be captured in that way," said Joseph.
"It's a very exciting discovery," said Karen Rehbock, assistant
to the director of the Institute for Astronomy. "It opens up a
lot of possibilities for researchers," she said.