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Gemini Prepares for Planet Searching with NICI

July 7, 2005

The Gemini community has embarked on a broad, multi-faceted search for planets around other stars. The prospect of answering the age-old question of how common solar systems like our own are in the universe captured the imaginations of astronomers who attended the June 2003 Aspen meeting, where new capabilities for the Gemini telescopes were imagined. In preparation for the next generation of planet-finding instruments, Gemini Observatory is actively looking for sub-stellar mass companions using the existing Adaptive Optics (AO) system Altair on Gemini North, and building the specialized near-infrared coronagraph (NICI) with its own AO system for Gemini South.

Figure 1. NICI assembled in early 2005 and ready for testing in the lab at Mauna Kea Infrared in Hilo Hawaii.

NICI is a dual-channel near-infrared imager and coronagraph. It uses an on-board curvature wavefront sensing AO system to produce near-diffraction-limited images and minimize scattered light. NICI has two Aladdin-2 InSb arrays sensitive from 1 to 5 microns, and a range of standard broad-band filters. The primary filters for finding planets will be a pair of high-quality 1.6-micron narrow-band methane filters, which are essential to increase the contrast between giant planets and the stars they orbit. NICI is equipped with a range of coronagraphic masks in the focal and pupil planes, including a rotating spider mask to block diffraction from the secondary support vanes.

NICI is currently nearing completion at Mauna Kea Infrared in Hilo, Hawaii, and is scheduled for deployment on the Gemini South telescope around the end of 2005. In preparation for a dedicated planet-finding campaign using NICI, Gemini is soliciting Letters of Interest from those in the community interested in proposing to conduct or participate in the NICI Planet Search Campaign. This request for letters will be followed by a Call for Proposals at the end of August 2005, which will provide details on proposal requirements and campaign parameters.

The purpose of the Letter of Interest is to allow Gemini to identify and work with potential proposing teams to define the campaign requirements in advance of the Call for Proposals. In addition, the Letters of Interest will provide information and guidance so that teams can better prepare to propose (the Call for Proposals will be open to all teams, even if a Letter of Interest was not submitted). Teams submitting proposals to execute the NICI Planet Search Campaign will be required to include details about team membership and partner participation, proposed observing strategies, possible external resources (student support, data from other facilities, etc.), data processing software, project schedule and data release plans. The requirements for proposals and the criteria for judging them will be explained in greater detail in the Call for Proposals; they are mentioned here so those interested in proposing will understand in advance what is likely to be required. Proposals will be due October 1, 2005.

NICI campaign proposals will be judged by the International Time Allocation Committee (ITAC), and the winning team selected by November 2005. The ITAC will allocate time to the NICI Planet Search Campaign team before filling the queue with the regular observing programs submitted to the national time allocation committees. The number of nights available for the survey will be approximately 50 nights distributed over two to three years. Gemini will work with the principle investigator of the winning team to finalize team membership to ensure that the science team has all of the resources needed to successfully meet the campaign goals. Teams that have strong international participation across the Gemini partnership will have a competitive advantage in the selection process.

Gemini will work with the winning team to conduct tests of observing and data reduction procedures and software during the instrument commissioning phase, and begin campaign observations shortly thereafter (anticipated to be during semester 2006A).

NICI will also be available for other research projects unrelated to the planet search campaign and time for these will be allocated through the regular TAC process. At this time, it is anticipated that approximately half of the NICI time will be reserved for regular PI-led and TAC-approved observations and half for the planet search campaign.