positive sources masquerading
as an exoplanetary transit event
are background eclipsing binaries or a variety of other variable
stars. By background, we mean a
star that’s nearly co-aligned with
the assumed exoplanet host star.
Its light mixes in with the target
star, mimicing a transit-like event.
High-resolution imaging allows us
to examine the area of space very
near a potential host star and detect (or not) these confounding
troublemakers.
Figure 2.
DSSI mounted on the
side port at Gemini
North. The instrument
(top silver box with
two EMCCD cameras
attached — one
on the left and one
towards the viewer)
is surrounded by
the larger standard
Gemini instrument
cage enclosure. The
small box attached
underneath is the
instrument control
computer.
The Scientific Purpose
You can see the DSSI mounted on a sidelooking port of Gemini North in Figure 2.
For scale, it’s about the size of a carry-on
suitcase. When we arrived at the telescope,
the mounting, focus, and computer connections and controls worked essentially
without a hitch. The Gemini day-crew members were super at their jobs and made the
setup process painless. But finding enough
small straps and bolts to lift the 35-kilogram instrument with the dome crane, and
then balancing it with the three other sideport monster instruments, proved to be a
fun challenge.
The scientific purpose of the observing run
was to use our high-resolution imaging ability to help the NASA Kepler spacecraft mission and the European Convection, Rotation
and Planetary Transits (CoRoT) satellite mission to validate small planets orbiting other
stars. Both of these missions provide timeseries light curves of stars, which can reveal
transit-like signals in them. They both also
rely on ground-based follow-ups for exoplanet confirmations. One of the largest false
6
GeminiFocus
Kepler, for example, has broad
point-spread functions covering
1-2 pixels, with each one spanning 4 arcseconds. Thus, the parameter space of close neighbors
to a t