XO Project

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. It is primarily funded by NASA's Origins Program and the Director's Discretionary Fund of the Space Telescope Science Institute.

Duties

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 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.

Equipment

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 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 .
In 2016 three similar double telescopes were operating, two in Spain and one in Utah.

Discoveries

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	Spectral type	Planet	Mass	Radius	Orbital period	Semimajor axis	Orbital eccentricity	Inclination	Discovery year
Moldoveanu	Corona Borealis			11.319	600	G1V	Negoiu	0.9	1.3	3.941534	0.0488	0	87.7	2006
XO-2N	Lynx			11.25	486	K0V	XO-2Nb	0.57	0.973	2.615838	0.0369	0	88.58	2007
XO-3	Camelopardalis			9.91	850	F5V	XO-3b	11.79	1.217	3.1915239	0.0454	0.26	84.2	2007
Koit	Lynx			10.78	956	F5V	Hämarik	1.72	1.34	4.12502	0.0555	0.0024	88.7	2008
Absolutno	Lynx			12.1	881	G8V	Makropulos	1.15	1.15	4.187732	0.0508	0.0029	86.8	2008
XO-6	Camelopardalis			10.28	760	F5V	XO-6b	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

Other Ground-Based Transit Surveys

Next-Generation Transit Survey
Trans-Atlantic Exoplanet Survey or TrES
HATNet Project or HAT
Kilodegree Extremely Little Telescope or KELT
SuperWASP or ''WASP''