David Bennett

Research Associate Professor,
Astrophysics and Cosmology

Research Interests

Prof. Bennett's research is focused on gravitational microlensing by stellar and planetary mass objects in the Milky Way and nearby galaxies. Microlensing refers to gravitational lensing when the lensed image separation is unobservably small. Time variable magnification (due to the lens motion) is observable.  Microlensing is particularly useful for the study of objects that emit little or no light, such as the dark matter that dominates the mass of the Galaxy, extra-solar planets, and isolated black holes.

Prof. Bennett was a founding member of the MACHO Project, which discovered the first known gravitational microlensing event in 1993. Theoretical work by Prof. Bennett (in collaboration with S.H. Rhie) demonstrated that gravitational microlensing is a particularly sensitive method for the detection of Earth-mass planets orbiting other stars, and observational work by Prof. Bennett's group was the first to demonstrate sensitivity to Neptune-mass planets in Jupiter-like orbits.

Much of Prof. Bennett's current research is focused on space-based microlensing observations. He has several Hubble Space Telescope observing programs, and has proposed to use a 30cm telescope on an approved interplanetary mission to observe microlensing events simultaneously from space and the Earth. The >200 million km separation between telescopes enables the distances to the lens objects to be estimated, and this will determine how much (if any) of the Milky Way's dark matter is in the form of stellar mass objects. His most ambitious space project is the proposed Galactic Exoplanet Survey Telescope (GEST) which will survey the Galaxy for planets down to the mass of Mars. If funded, GEST will provide our first estimate of the abundance of Earth-like planets throughout our Galaxy.

Selected Publications

“Possible Gravitational Microlensing of a Star in the Large Magellanic Cloud,” C. Alcock,

et al., Nature 365, 621 (1993).

“Detecting Earth-Mass Planets with Gravitational Microlensing,” D.P. Bennett and S.H. Rhie, Astrophys. J. 472, 660 (1996).

“The MACHO Project: Microlensing Results from 5.7 Years of LMC Observations,” Alcock, et al., Astrophys. J. 542, 281 (2000).

“Gravitational Microlensing Events Due to Stellar Mass Black Holes,” D.P. Bennett, et al., Astrophys. J. 579, 639, (2002).

“The Galactic Exoplanet Survey Telescope (GEST),” D.P. Bennett, et al., Proc. SPIE , 4854, 141 (2003).

Full Curriculum vitae (pdf)
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