GeminiFocus July 2017 | Page 20

Figure 7 . Members of the ‘ Alopeke team work with Gemini engineers on Maunakea . Photo credit : Joy Pollard
Figure 8 . This image shows some steps in the process of Speckle Image reconstruction using Fourier transform techniques . Left : A single 50 millisecond speckle image of a star . Middle : a conventional image typical of a groundbased telescope . Right : A reconstructed image revealing the star is really a close binary pair . The boxes are
~ 1 arcsecond on a side . Video credit : Elliott Horch
Figure 9 . Artist ’ s impression of the TRAPPIST-1 exoplanetary system showing three Earthsized planets in orbit around the low-mass star . Observations characterizing this system were made using DSSI on Gemini South last year .
Credit : Robert Hurt / JPL / Caltech
Electron Multiplying CCD cameras , and both speckle and wide-field imaging capabilities with standard Sloan Digital Sky Survey filters . One of the unique features of DSSI is its robust and compact design , and ‘ Alopeke will take full advantage of this .
‘ Alopeke will be permanently mounted on Gemini North in a location that does not interfere with the standard instrument ports — so users can operate it in visitor mode ( when time is allocated through the Time Allocation Committee ) without the additional overhead of mounting and then removing the instrument . This innovative placement will permit us to offer ‘ Alopeke at each Call for Proposals . It will be remotely operable
from the Hilo Base Facility . The instrument team will make the observations and provide their standard pipeline-reduced data products to Principal Investigators . We will make the data available ( after the standard proprietary period ) via the Gemini Science Archive ( in a reduced-effort mode ).
In addition to other types of science , speckle observations are viewed as a critical part of the exoplanet validation process , providing essentially the only method to validate small , rocky planets . ‘ Alopeke will be ideal for characterizing a system of low mass planets , such as that orbiting the late M-type star , TRAPPIST-1 . Previous observations of that star , which is only about 8 % the mass of our Sun , showed variations in the flux which suggested the presence of several Earth-sized planets . The situation could be much more complicated than that , however , if TRAPPIST-1 were part of a binary or multiple star system . The resolution afforded by DSSI on Gemini South allowed astronomers to see closer to TRAPPIST-1 than the orbit of Mercury to the Sun , and effectively ruled out the existence of any stellar or substellar companion .
We expect ‘ Alopeke to have even better performance than DSSI . It will be mounted on the Gemini North telescope permanently and will be available for continued observations of this sort in the future .
— Alison Peck and Steve B . Howell
For more information on the Gemini Visiting Instrument Program , what capabilities to expect in coming semesters , or how you can bring your instrument to Gemini , email : gemini-vip @ gemini . edu
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