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Project Progress

As in previous years, my major effort during the past year continues to be the VYSOS project. VYSOS (Variable Young Stellar Objects Survey) consists of two telescopes mounted in Hawaii at Mauna Loa. The purpose of our project is to have these two fully robotic telescopes monitor all star forming regions along the entire Galactic plane within about 2 kpc and visible from Hawaii (i.e., north of declination -40) in order to understand the photometric variability of solar-like young stars. Such variability can have a number of causes, mainly accretion activity, starspots, eclipses by companions or dustclouds, and magnetic reconnection events. Almost nothing is known about the timescales and amplitudes of these phenomena, and the VYSOS project is putting this on a firm footing by monitoring many tens of thousands of young low-mass stars over the next decade or more.

To survey larger swaths of the sky, we have installed a 135 mm apochromatic refractor at the Mauna Loa Observatory. It has a 2.9 × 2.9 degree field and can reach 17th magnitude in 5-minute exposures. We are currently performing surveys of large areas of the Milky Way with this telescope. This small but highly efficient telescope will also be used for monitoring bright comets as they enter the inner Solar System; in particular we are starting to monitor the new comet PanSTARRS, which is brightening at the moment. Our refractor has already obtained over 50,000 images. During the previous year, we had problems with the dome for this telescope, but these were solved and we have resumed observations. Thanks to the exceptionally good weather during the last year we have acquired an enormous amount of data.

Last year we received a grant that has enabled us to acquire a second 135 mm apochromatic refractor, which has now been delivered. This will be mounted next to the first refractor, and the two will perform simultaneous observations in an r- and an i-filter, so we get information not only on variability but also on color changes.

We have started a collaboration with Keivan Stassun at Vanderbilt University, who is now modifying a reduction package that enables us to efficiently and autonomously reduce the vast data sets produced by the telescopes. With this package we are able to efficiently reduce the huge number of observations acquired so far. The diagram shows an example of a light curve of a new eclipsing binary. It is faint (r ~15 mag) as can be seen from the image. It is remarkable that even for such a faint object it is possible to derive detailed light curves. Josh Walawender left the project in April 2011 to take up a faculty position at University of Hawaii Hilo, and a new postdoc, Hsin-Fang Chiang, took his place in early November 2011. Josh is currently back at UHNAI to help with the installation of VYSOS-5B.
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