Examining Planets around Other Stars through Very Precise Infrared Imaging at the Keck Observatory

California Association For Research In Astronomy, Kamuela HI

Investigators

Abstract

To get the sharpest images of planets, stars and galaxies, astronomers must use innovative techniques that correct for the blurring of images caused by turbulence in the earth's atmosphere. One of the most exciting uses of this technology is imaging planets around nearby stars. This team aims to build a device that works using infrared light from the host star (the star that the planet orbits). The device will be used on one of the world's largest telescopes, the Keck II telescope on Maunakea, Hawaii. The system works by rapidly changing the shape of mirrors inside the instrument to counteract the effect of "ripples" in the earth's atmosphere. The principal investigator, along with a postdoctoral researcher, summer interns, and graduate and undergraduate students from Hawaii and California, will search for planets around 150 small "dwarf" stars. Their results will be made available to the broader science community through the Keck Data Archive. Driven by the scientific desire to study young planetary systems around low-mass M-dwarfs, and the practical need to develop near-infrared (NIR) wavefront sensing and adaptive optics (AO) capabilities for the upcoming generation of 30 meter class segmented-mirror telescopes, the proposers seek to produce a system that operates in the L-band for the Keck observatory. The IR detector technology needed for such a system now exists (in large part through funding by NSF) and will be used by the proposers to build a near-IR, high-order, pyramid wavefront sensor for the Keck II telescope. This system will then be used to conduct an L-band (3 micron) coronagraphic imaging survey of ~150 M dwarfs with the Keck facility instrument, NIRC2. The team will conduct follow-up low-resolution slit spectroscopy observations of any exoplanet candidates found in the L-band survey. Note that M-dwarfs are too faint to observe with sufficient contrast and spatial resolution to detect (even massive) exoplanets with existing optical AO systems. The development of the proposed NIR wavefront sensing system at Keck may be viewed as an enabling technology that could lead to the fabrication of similar units at other, publicly available observatories. It should also be noted that NIR wavefront sensing can be used to extend the performance of natural guide star AO systems to fainter targets, and to increase the sky coverage to regions where only optically obscured or very red guide stars are available.