Figure 6 . Artist ’ s concept of what the view might be like from inside the TRAPPIST-1 exoplanetary system , showing three Earthsized planets in orbit around the lowmass star . This alien planetary system is located only 12 parsecs away . Gemini South telescope imaging , the highest resolution images ever taken of the star , revealed no additional stellar companions , providing strong evidence that three small ( probably rocky ) planets orbit this star . Image credit : Robert
Hurt / JPL / Caltech Figure 7 . Detection limit analysis for the June
22 , 2016 , Gemini- South observation of TRAPPIST-1 . Detection limits observed at 692 nm ( top ) and at 883 nm ( bottom ). The red line represents the relative 5σ limiting magnitude as a function of separation from 0.027 to 1.2 arcseconds . At the distance of TRAPPIST-1 , these limits correspond to 0.32 – 14.5 AU . The two listed limiting magnitudes given for reference are for angular separations of 0.1 and 0.2 arcsecond .
clude that the galaxy ’ s mass is approximately 10 12 M Sun
, and that the total galaxy is 99.99 % dark matter . One specific problem this example presents is that the formation of stars is predicted to have maximum efficiency at this mass regime . Dragonfly 44 , a confirmed member of the Coma cluster exhibiting a regular morphology , has formed 100 times fewer stars than expected . A Gemini press release
provides some more information and links to high-resolution images ; full results are published in The Astrophysical Journal Letters .
Confirming Nearby Exo-Earths
The Differential Speckle Survey Instrument ( DSSI ) visited Gemini South for the first time in June 2016 and is already delivering exciting results , including the validation of nearby Earth-like exoplanets . Previous observations using the TRAnsiting Planets and PlanetesImals Small Telescope ( TRAPPIST ) had shown variations in the light curve of the star TRAPPIST-1 , implying the presence of several Earth-sized planets ( Figures 6 and 7 ). Steve Howell ( NASA Ames Research Center ) and colleagues used high-resolution images from Gemini to confirm the small size and mass of these suggested planets by ruling out the presence of a very nearby companion . DSSI on Gemini provides the highest resolution images available to astronomers anywhere and here achieved a resolution of 27 milliarcseconds , or 0.32 astronomical units at the 12-parsec distance of TRAP- PIST-1 .
The host star , TRAPPIST-1 , is a late M dwarf . Such cool stars are interesting targets because any terrestrial planets around them would have short periods ( of days ) and be detectable with current technology . At least two of the three known planets in this case are very close to the star , so too hot even to be in the habitable zone . The orbit of the third planet is somewhat uncertain now . See the Gemini press release and The Astrophysical Journal Letters for full results .
24 GeminiFocus January 2017 | 2016 Year in Review