December2006 but Hokupa‘a-85 was a very useful test bed and
We are currently taking the next steps in
pathfinder for NICI which uses a very similar AO
transforming the Gemini South telescope into a
system.
powerful AO facility. Early in semester 2007A, we will complete the commissioning of NICI on
ALTAIR is now in regular use at Gemini North and
the Gemini South telescope. This specialized AO
is delivering excellent science. Six years after the
system was built by Mauna Kea Infrared in Hilo,
first AO observations at Gemini it is rewarding to
Hawai‘i, and includes its own 85-element curvature-
realize that close to 20% of the 300 refereed papers
sensing AO system which has evolved from the
based on Gemini data involved the use of AO
successful Hokupa‘a-36 system. Funded by NASA,
(Hokupa‘a-36 and ALTAIR) on the Gemini North
the NICI instrument will be devoted to the search
telescope.
for large Jovian planets around nearby stars in the southern hemisphere.
Brown Dwarf Companions at Solar System Scales
Almost in parallel with NICI, the integration of the Multi-Conjugate Adaptive Optics (MCAO)
In their Hokupa‘a-36 study “Crossing the Brown Dwarf Desert Using Adaptive Optics: A very Close L-Dwarf Companion to the Nearby Solar Analog HR 7672”, Michael Liu (University of Hawai‘i) and his team showed that brown dwarf companions do exist at separations comparable to those of the giant planets in our solar system. (For more details see paper by M. Liu et al., 2002, ApJ, 571, 519-527.)
system (CANOPUS) is now underway at Gemini South. Instead of one deformable mirror and one laser guide star, as in the ALTAIR LGS system, CANOPUS will deploy three deformable mirrors and five laser beams. This will enable an AOcorrected field of 80 arcseconds (four-times what is currently available). A new 50-watt solid-state laser is being procured from Lockheed Martin Coherent Technologies (LMCT), and will be delivered to our Chile facilities in mid-2007. All of this development means that the year 2007 at Gemini South will be dominated by CANOPUS integration and commissioning. Our current schedule is to offer CANOPUS for general science use with the 4 x 4K
In order to take advantage of the laser guide star
near-infrared imager Gemini South adaptive optics
(LGS) mode of ALTAIR, Gemini’s solid-state
imager (GSAOI), followed by the near infrared
sodium-line laser arrived in Hawai‘i in February
cryogenic multi-object spectrograph FLAMINGOS-2
2005, and was first successfully propagated on the
in 2008.
sky on May 2, 2005. It turns out that attaching the laser to the telescope and shining it on the sky was the “easy” part. We then spent more than a
Low Mass Binary Companions
year solving several complex issues related mainly to the laser launch telescope and the ALTAIR LGS
In searching for giant planets around nearby
subsystems. As this issue of GeminiFocus goes to
stars with Hokupa‘a-36, Laird Close (University
press, we are in the final stage of commissioning the
of Arizona) and his collaborators discovered
combined ALTAIR LGS system and its integration
a population of brown dwarfs as binary
with NIRI and NIFS. We are now ready for
companions to low-mass stars, changing our view
science with ALTAIR in both the LGS and natural
of the formation mechanism of such objects.
guide star (NGS) modes. With ALTAIR we have
Low-mass stars and brown dwarfs come in pairs
demonstrated, as was previously done at the W.M.
more often than their more massive cousins, and
Keck Observatory, that transforming an AO NGS
they form much tighter orbiting systems. (For
system into an LGS system is achievable. ALTAIR
more details see paper by L. Close et al., 2004,
can be switched quickly between its NGS or LGS
ApJ, 587, 407-422.)
modes on demand during the course of nightly
14
queue-scheduled operations.
Gemini Observatory