GeminiFocus January 2018 | Page 4

In their Nature paper ( published online ; November 20 , 2017 ), Karen Meech and her collaborators argue that while ‘ Oumuamua ’ s colors ( and therefore , possibly , composition ) are similar to those of outer Solar System bodies , its shape isn ’ t : the large variation in brightness , by an order of magnitude over the object ’ s 7.3-hour rotation period , points to an extremely ( for Solar System standards ) elongated object ten times longer than it is wide .
Two other teams also used Gemini data to study ‘ Oumuamua , and Gemini ’ s new Chief Scientist , John Blakeslee , summarizes these results in this issue ’ s lead science article starting on page 4 . Will we get another chance to study interstellar asteroids like ‘ Oumuamua ? Certainly yes ; a recent study ( Trilling et al ., arXiv : 1711.01344 ) suggests that we ’ ll have at least one opportunity per year once the Large Synoptic Survey Telescope ( LSST ) starts operations adjacent to Gemini South on Cerro Pachón .
Technical Thrills
Moving on to technical activities , on October 26th , just as ‘ Oumuamua was making its way through the Solar System , staff at Gemini South propagated the Gemini Multi-conjugate adaptive optics System ( GeMS ) laser guide star constellation for the first time with the new Toptica laser . This was the first of several important steps designed to restore GeMS to its intended performance . The new Natural Guide Star Wavefront Sensor ( NGS WFS 2 ), expected to be commissioned later next year , will be an order of magnitude more sensitive than the current one , providing up to a 30 % increase in the fraction of the sky accessible to GeMS .
A new ground Deformable Mirror , DM0 , to replace the one that failed shortly after commissioning , will also be received later next year . After that , efforts will concentrate on GeMS ’ Real Time Computer ( RTC ), not only to improve its reliability but also to support the new generation of visiting instruments , almost all of which are designed to exploit GeMS ’ unique capabilities .
In the North , we have commissioned a new visiting instrument : ‘ Alopeke ( BTW : a huge THANK YOU to the ‘ Alopeke team for their cooperation during the ‘ Oumuamua observations which interrupted their work ). Many Gemini users are familiar with our visiting Differential Speckle Survey Instrument ( DSSI ). Well , ‘ Alopeke is DSSI on steroids : it is capable of diffraction-limited optical imaging ( Full-Width at Half-Maximum 0.016 arcsecond at 500 nanometers ) of targets as faint as V ~ 17 magnitude over a 6.7 arcsecond diameter field-of-view ( as opposed to DSSI ’ s 2.8 x 2.8 arcsecond field ). It also includes Sloan Digital Sky Survey as well as narrow band filters , and offers a wide-field mode ( 1 arcminute diameter ) that , while not reaching full speckle performance , can still clock an impressive 26 frames per second .
‘ Alopeke is now permanently mounted at Gemini North , and I urge the Gemini community to take a closer look at its capabilities . While it was motivated by the desire to understand how many stars that host planets are in binary systems , ‘ Alopeke also holds tremendous potential for the study of crowded stellar fields … the centers of Galactic globular clusters or Local Group galaxies come to mind .
More Exciting News and Initiatives !
On the governance side , the last three months have marked two milestones for the National Center for Optical and Infrared Astronomy ( NCOA ): the operations and management plan developed for NCOA was validated first by an external panel
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