Jacob Howell, Astronomy Major, Explores Mysterious Exploding Stars

Jacob Howell processed observations taken with the Hobby Eberly Telescope, one of the world's largest optical telescopes and an instrument for which Penn State is a major partner.

Tonight, somewhere nearby in the universe, a star will explode. Sometimes that explosion is catastrophic, as when a massive star explodes in a supernova. Other times the explosion is just a minor detonation -- called a nova -- on a star's surface. And every now and then, the nature of the explosion is mysterious.

In April 2010, undergraduate researcher Jacob Howell and his advisor Professor Derek Fox from Penn State's Department of Astronomy and Astrophysics were on the team that caught one such mysterious explosion in the act. Howell and Fox use the Palomar Transient Factory, an automated survey that searches the night sky for sudden changes in brightness. When a sudden flare occurred in the outskirts of a small spiral galaxy near the Milky Way, Howell and Fox were among the first to follow up.

The event is difficult to explain, Howell said, because the flare is not bright enough to be a supernova, yet it is far brighter than a nova. "There is a pretty big gap between the highest energy novae and the lowest energy supernovae. There should be something that fits into that space."

But what? As an undergraduate research assistant during the summer, Howell's job was to help answer that question. Howell processed observations taken with the Hobby Eberly Telescope, one of the world's largest optical telescopes and an instrument for which Penn State is a major partner.

Howell-Jacob

Jake Howell studies the light spectrum of a mysterious cosmic explosion.

"We use a spectrograph, which takes the light that's coming in and breaks it apart using a series of slits," Howell explained. "The slits work like prisms, separating the different colors in the light." To show how bright the event is at each color, Howell used image-analysis tools to make a light spectrum.

The light spectrum confirmed that the flare in brightness came from gas exploding outward at almost 2-million miles per hour.

So what caused the explosion? Nobody knows -- yet. "That's what makes this event interesting - it's on the cutting edge," said Howell. "I enjoy science so much because I can describe things that I don't really understand, and then start to understand them through observations."

"Eventually we'll have some understanding of what's going on," Howell added. The object Howell studied has since faded away, but the Palomar Transient Factory continues to scan the sky every night. And every night is another chance to find and study more of these mysterious explosions.