Planets discovered or observed by STARE
The STARE project has to-date observed two planets orbiting other stars:
Planet HD209458b was first discovered using the radial velocity method, but was subsequently the first planet observed to transit. Click on curve for more information. Planet TrES-1 was our first planet discovery, observed with the STARE telescope in the summer of 2003. It was the first transiting planet discovered by a small-aperture, wide-field survey. Click on curve for more information.
Auriga Field Variable Star Light Curves
For each of the 24,000 stars in the Auriga field of view, photometry data from the STARE instrument can be used to produce a light curve -- a plot of the brightness variation of the star in time. Most stars are essentially constant in brightness, but several percent of the stars observed by STARE are variable. The figures below are a sampling of different variable types: eclipsing, delta scuti, and cepheid. The lightcurves were produced by folding data (taken over a 45 day span in 1997) over the period of variability (determined through spectrum analysis). The change in brightness is measured in magnitudes, where a magnitude change of 0.1 corresponds roughly to a 10% change in stellar brightness; brightness increases upwards. These curves illustrate the types of "false alarms" we must weed through in order to find real transits like those above.
Click on curves to view larger image.
Star 306 consists of a pair of stars which eclipse each other. They are so close together that they are pulled out of a spherical shape by tidal forces. The light curve between eclipses is not flat, because of the changing aspect of the distorted stars as they move in their orbits. Star 315 is a suspected delta scuti pulsating variable. Light curves of this type of variable are almost exact reflections of the radial-velocity curves. Typical periods range from .01 to .2 days and amplitudes range from .003 to .9 mag. Star 875 is a suspected delta cepheid pulsating variable. Delta cepheids are fairly young stars that have left the main sequence and evolved into the instability strip of the H-R diagram. They display a certain relationship between the shapes of their light curves and their periods. Star 887 is a suspected beta cepheid pulsating variable. The curves of these variables are similar in shape to average radial-velocity curves, but lag in phase by a quarter of the period so that maximum brightness corresponds to maximum contraction. Star 1025 is another detached binary, but with a much smaller (4%) primary eclipse. The very small eclipse depth may indicate that one star is only about 0.2 times as large as the other, or that the orbital plane is tilted to our line of sight, so that grazing eclipses occur. The eclipse depth in this case is about 4 times as large as one would expect for a Jupiter-sized planet.