January 3, 2000
Contact: Chris Curran
513-556-1806
chris.curran@uc.edu

PHYSICIST PROBES ORIGINS OF STAR BIRTH

Cincinnati -- While new parents worldwide celebrate the births of their millennial babies, UC physicist Margaret Hanson explores the mysteries of another type of birth. Hanson wants to understand how stars are born.

"I'm trying to find stars still inside the womb, which is hard. The child can be around for years, but it's only inside the womb for nine months."

It's a difficult field of study, even when looking at stars in our own Milky Way galaxy. That's because the nascent stars are generally obscured by clouds of interstellar dust.

"There's an awful lot of dust and gas in the interstellar medium," explained Hanson. "That has a tendency to scatter the light like a fog. You can't see through it."

So, instead of working at visible light wavelengths, Hanson studies stars using infrared light or IR. "If you go to the IR, the light is more efficient at passing through this gas and dust, so I can detect light originating further inside our galaxy than has been seen before in the optical."

Hanson's primary targets are giant stars, many times the mass of our simple yellow sun. She hopes to answer a question that has puzzled astronomers for years. "There's a problem in astronomy that remains unsolved. How do stars that are many times the mass of our sun form? We see these stars all around us, but how did they form?"

The first problem is finding the stars and catching them at the moment of birth. "To find massive stars in the process of forming is very difficult," admitted Hanson. "It's like finding a needle in a haystack. There's a huge number of stars in the galaxy, but only a very small fraction of them are massive stars that are currently forming."

A second mystery of star birth that interests Hanson is the notion of "star-bursting." About ten percent of all galaxies are producing new stars at an enormously high rate. She was brought in as a collaborator on a recent project to help understand how many stars were actually forming in these galaxies, how long a star-bursting event lasts, and what might have triggered the star-bursting event in the first place.

Hanson has most recently used telescopes at the University of Arizona, The National Observatories at Mexico, on Baja, and soon will be traveling to Chile, to use the 8.0-meter, Very Large Telescope, all to search for and then study these heavily shrouded young massive stars. She also hopes to extend her infrared observational techniques to space, having recently applied for time on the Hubble Space Telescope.