Svetlana Berdyugina

(1)    Kiepenheuer Institut fuer Sonnenphysik, Freiburg, Germany

(2)    IfA, UH (visiting scientist)

Title:

High-Sensitivity  Double Image Polarimeter DIPOL-2 at UH88: Exoplanets, Interacting Binaries, Interstellar Medium, Asteroids, etc.
 
Abstract:
 
Polarimetry is a powerful technique to see beyond the spatial resolution of telescopes. It was crucial for detecting for the first time exoplanet reflected light, seeing accretion disks and jets in young stars and interacting binaries, unifying the Seyfert I and II galaxy classes, detecting large-scale alignment of quasars, etc.

Recently we have designed and built a unique double-image broad-band polarimeter DIPOL-2 (Piirola et al. 2014) which is capable of measuring polarization with the sensitivity down to at least 5x10^-6 in three passbands simultaneously. It consists of a rotatable superachromatic retarder plate (half-wave or quarter-wave), a plane parallel calcite plate, two dichroic beam-splitters, and three CCDs, one for each passband. Simple yet effective design with small number of optical elements and moving mechanical parts makes DIPOL-2 a highly versatile and reliable instrument with negligible instrumental polarization, very well suitable for observations with remotely controlled telescopes.

Three working copies of this polarimeter have been deployed at several telescopes: Swedish Academy KVA 60cm and UK 4m Wilhelm Herschel telescopes on La Palma, UH88 telescope on Mauna Kea, and Tohoku University 60cm telescope on Haleakala. All but WHT are operated remotely. From the 2015B semester DIPOL-2 at UH88 is offered to all IfA scientists.

In this talk I will describe technical aspects of the instrument and current scientific programs and results obtained with DIPOL-2 at various telescopes as examples. These include orbital and physical properties of exoplanets, studies of binaries with accretion disks, mapping galactic interstellar matter and magnetic field, and asteroid characterization.