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Students Win Research Awards

Bowler Receives ARCS Award

Bowler with ARCS folks.

ARCS-Honolulu Chapter Secretary Carol Wood, left, and ARCS President Cynthia Hunter with Brendan Bowler. Photo courtesy ARCS.

IfA graduate student Brendan Bowler has won the 2010 Columbia Communications Award in Astronomy given by the Achievement Rewards for College Scientists (ARCS) Foundation for his studies of exoplanets.

In his work with John Johnson, Bowler studied planets orbiting stars more massive than one and a half times the mass of the Sun. While over 450 exoplanets have been discovered, very few of them orbit these intermediate-mass stars, and none of them orbit at a distance less than 0.6 astronomical units (about 56 million miles or 90 million km). What is surprising is that the frequency of planets orbiting these intermediate-mass stars is significantly higher than for planets around Sun-like stars. This suggests that planet formation is more efficient than expected in these systems, a concept that challenges current models of planet formation.

Now, for his PhD dissertation under the direction of Michael Liu, Bowler is doing direct imaging of nearby low-mass stars (ones smaller than the Sun) to search for giant planets orbiting them. This research may help to clarify which of the two competing models of planet formation, core accretion or disk instability, is correct.

The award is $5,000.

Zahid Wins Research Award

Jabran Zahid

Jabran Zahid

IfA graduate student Jabran Zahid has won a University Research Council Student Excellence in Research Award for a project that measured the luminosity, masses, and chemical enrichment of distant galaxies. The light we see from these galaxies left them seven billion years ago and therefore studying them gives us a glimpse of the population of star-forming galaxies at about half the current age of the Universe. Metals in galaxies are created and accumulated through the process of massive star formation and subsequent death.

In this way, measuring the metallicity of a galaxy—the proportion of the gas mass that is made up of elements other than hydrogen or helium—provides a record of its star formation history, a crucial aspect of galaxy evolution. Metallicity increases with increasing luminosity and stellar mass, so the more luminous or massive a galaxy, in general, the higher its metallicity. However, the mass-metallicity and luminosity-metallicity relations evolve with time, and this evolution provides important constraints on the process of galaxy evolution as a whole.

Zahid worked on this project with IfA astronomers Lisa Kewley and Fabio Bresolin. Their paper, "The Mass-Metallicity and Luminosity-Metallicity Relation from DEEP2 at z ~ 0.8," has been submitted to the Astrophysical Journal, and a subsequent paper examining the origin and evolution of these relations will be submitted soon.