stars). But Howell and his team’s research
almost certainly shows the object to be a Ju-
piter-like gas-giant exoplanet with a “puffed
up” atmosphere due to exposure to the tre-
mendous radiation from its host star. is the highest-quality image that a telescope
can produce, effectively obtaining space-
based resolution from the ground — making
these instruments superb probes of extraso-
lar environments that may harbor planets.
‘Alopeke has an identical twin at the Gem-
ini South telescope in Chile, named Zorro,
which is the word for fox in Spanish. Like
‘Alopeke, Zorro is capable of speckle imag-
ing in both blue and red wavelengths. The
presence of these instruments in both hemi-
spheres allows Gemini Observatory to re-
solve the thousands of exoplanets known to
be in multiple star systems. The discovery of planets orbiting other stars
has changed the view of our place in the
Universe. Space missions like NASA’s Kepler/
K2 Space Telescope and the Transiting Exo-
planet Survey Satellite (TESS) have revealed
that there are twice as many planets orbiting
stars in the sky than there are stars visible to
the unaided eyes; to date the total discovery
count hovers around 4,000. While these tele-
scopes detect exoplanets by looking for tiny
dips in the brightness of a star when a planet
crosses in front of it, they have their limits.
"Speckle imaging is experiencing a renais-
sance with technology like fast, low noise
detectors becoming more easily available,"
said team member and ‘Alopeke instrument
scientist Andrew Stephens at the Gemini
North telescope. "Combined with Gemini's
large primary mirror, ‘Alopeke has real poten-
tial to make even more significant exoplanet
discoveries by adding another dimension to
the search."
First proposed by French astronomer An-
toine Labeyrie in 1970, speckle imaging is
based on the idea that atmospheric turbu-
lence can be “frozen” when obtaining very
short exposures. In these short exposures,
stars look like collections of little spots, or
speckles, where each of these speckles has
the size of the telescope’s optimal limit of
resolution. When taking many exposures,
and using a clever mathematical approach,
these speckles can be reconstructed to form
the true image of the source, removing the
effect of atmospheric turbulence. The result
12
GeminiFocus
“These missions observe large fields of view
containing hundreds of thousands of stars,
so they don’t have the fine spatial resolu-
tion necessary to probe deeper,” Howell said.
“One of the major discoveries of exoplanet
research is that about one-half of all exo-
planets orbit stars that reside in binary sys-
tems. Making sense of these complex sys-
tems requires technologies that can conduct
time sensitive observations and investigate
the finer details with exceptional clarity.”
“Our work with Kepler-13b stands as a
model for future research of exoplanets in
multiple star systems,” Howell continued.
“The observations highlight the ability of
high-resolution imaging with powerful tele-
scopes like Gemini to not only assess which
stars with planets are in binaries, but also
robustly determine which of the stars the
exoplanet orbits.”
October 2019