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She
Has Star Power
Planet Hunter Returns to Campus
Astronomer
Debra Fischer (M.S., '87) knows a lot about velocity
and has a surprising amount herself. If she's not at a blackboard drawing
diagrams to explain planetary movement, she's offering a physics test
to an unwitting visitor. "Okay," she says, jumping out of her
chair, "if I have two identical balls on the edge of this table,
and drop one off the edge, but launch the other at a velocity of 100 miles
an hour, which one hits the ground first?"
For the last seven years, the SFSU alumna has been working with the California
and Carnegie Planet Search Project, the successful planet-hunting team
credited with discovering most of the 110 known planets outside of our
solar system.
While earning her master's in physics, Fischer worked with astronomer
Geoff Marcy, who co-founded the project at SFSU in 1983.
Although they still do research together, the original members of the
SFSU project dispersed to other institutions; Marcy and Fischer relocated
to UC Berkeley in 1999, and Paul Butler (B.A.,'85, B.S., '86, M.S.,
'89) now works for the Carnegie Institution in Washington, D.C.
Fischer came back to SFSU this fall as an assistant professor in the Physics
and Astronomy Department, drawn by the opportunity to combine research
and teaching. "One of the things I want to bring to SFSU is research,"
she says, "to make the things [students] learn meaningful and real.
It makes such a difference in their lives to actually go to the telescope
and collect data."
The hunt for planets intensified after the first extra-solar planet was
discovered by a Swiss astronomy team in 1995. Marcy and his SFSU team
caused a flurry of international excitement when they confirmed the existence
of three more planets the following year, including the first multi-planet
system.
In 1997, Fischer rejoined Marcy at SFSU as a post-doctoral planet-hunter.
Over the next two years, she would be credited with discovering three
planets herself.
But even while fielding questions from CNN and being filmed for documentaries
in the late '90s, Fischer was focused on her scientific goals. "I
thought of all the media exposure as educational outreach," she says.
"What I found really exciting was cracking open this new area of
science and getting more pieces of the puzzle."
Fischer and her team use an observation technique that measures the metal
content of stars to find planets. Stars richer in metals are more likely
candidates.
Using telescopes at UC's Lick Observatory, Fischer and her colleagues
look for "wobble," the  fluctuations
in a star's velocity, that signals the presence of a planet. But even
once a potential planet is identified, it must be monitored for a full
orbital cycle which, depending on its distance from the star, could be
a few days or a few years.
"These discoveries are new chapters in basic astronomy books,"
Fischer says.
"Before, the search for extraterrestrial intelligence was taken less
seriously. But when planets were discovered orbiting nearby stars, it
shifted the entire focus of NASA. It put them on the road to finding Earth-like
planets."
Using data from Fischer's team and others, NASA in 2010 will launch a
new satellite telescope into solar orbit to find planets in zones scientists
think are likely to support life. This mission will search for smaller
planets that are more likely to be terrestrial, or Earth-like, rather
than gaseous like Jupiter. If found in the inhabitable zone, the surface
of a terrestrial planet would allow water to collect in a way that might
support life.
Fischer cites her early research work as the inspiration for her career.
"I became an astronomer because I had the opportunity to work with
Professor Marcy and do research," she says. It's this same interest
she hopes to excite in her own students. "The students at SFSU span
an incredible range.… When you give them a challenge, they rise
to the occasion."
In addition to planet-hunting, Fischer is spearheading efforts to bring
a $6.5 million robotic telescope to Lick Observatory. This "automated
planet finder" will be the world's first telescope completely dedicated
to finding new planets. Fischer's team and their students will use the
telescope 365 nights a year to track selected stars that may host smaller,
terrestrial planets. The installation is expected to be completed by December
2004.
Fischer doesn't attribute her team's success to high-tech telescopes.
"Teamwork," she says. "We work well together because we
all give this project everything we've got."
Still up in the air on those balls Fischer mentioned at the beginning
of the story? They both hit at the same time.
--
Jennifer Roolf
 
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