The XO Project is an international team of amateur and professional astronomers tasked with identifying extrasolar planets. They are led by Peter R. McCullough of the Space Telescope Science Institute.[1] It is primarily funded by NASA's Origins Program and the Director's Discretionary Fund of the Space Telescope Science Institute.[2] [3]
Preliminary identification of possible star candidates starts at the Haleakala telescope in Hawaii by a team of professional astronomers. Once they identify a star that dims slightly from time to time (the transit method), the information is forwarded to a team of amateur astronomers who then investigate for additional evidence suggesting this dimming is caused by a transiting planet. Once enough data is collected, it is forwarded to the University of Texas McDonald Observatory to confirm the presence of a transiting planet by a second team of professional astronomers.
McCullough and his team employed a relatively inexpensive telescope called the XO Telescope, made from commercial equipment, to search for extrasolar planets. The construction of the one-of-a-kind telescope cost $60,000 for the hardware, and much more than that for the associated software. The telescope consists of two 200-millimeter telephoto camera lenses, and resembles binoculars in shape. It is similar to the TrES survey telescope. It stands on the summit of the Haleakalā volcano and 3,054 m (10,000 foot) in Hawaii. Their first discovery of a Jupiter-sized planet orbiting a Sun-like star 600 light-years from Earth in the constellation Corona Borealis—XO-1b—was reported May 16, 2006 on Newswise.
In 2016 three similar double telescopes were operating, two in Spain and one in Utah.[4]
The XO telescope has discovered six objects so far, five are hot Jupiter planets and one, XO-3b, may be a brown dwarf.
| Star | Constellation | Right ascension | Declination | App. mag. | Distance (ly) | Spectral type | Planet | Mass | Radius | Orbital period (d) | Semimajor axis (AU) | Orbital eccentricity | Inclination (°) | Discovery year | |
|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|---|
| 11.319 | 600 | G1V | 0.9 | 1.3 | 3.941534 | 0.0488 | 0 | 87.7 | 2006 | ||||||
| 11.25 | 486 | K0V | 0.57 | 0.973 | 2.615838 | 0.0369 | 0 | 88.58 | 2007 | ||||||
| 9.91 | 850 | F5V | 11.79 | 1.217 | 3.1915239 | 0.0454 | 0.26 | 84.2 | 2007 | ||||||
| 10.78 | 956 | F5V | 1.72 | 1.34 | 4.12502 | 0.0555 | 0.0024 | 88.7 | 2008 | ||||||
| 12.1 | 881 | G8V | 1.15 | 1.15 | 4.187732 | 0.0508 | 0.0029 | 86.8 | 2008 | ||||||
| Camelopardalis | 10.28 | 760 | F5V | 4.4 | 2.07 | 3.76 | 0.082 | 0 | 86.0 | 2016 | |||||
| XO-7 | Draco | 10.52 | 763 | G0V | XO-7b | 0.71 | 1.373 | 2.8641424 | 0.04421 | 0.038 | 83.45 | 2019 |
A subset of XO light curves are available at the NASA Exoplanet Archive.