Astronomers discovered first solar system outside our own on this day in 2001

Astronomers found the first solar system outside our own on this day back in 2001 and noted that multiple planets travel round the same star in circular orbits. A team of NASA astronomers had announced the discovery of the second planet orbiting near the star 47 Ursae Majoris on August 15, 2001. The scientists noted that the two planets around the star 47 Ursae Majoris travel in a nearly circular orbit at a distance that in our solar system would place them beyond Mars but within the orbit of Jupiter. 

Back then, astronomy professor Geoffrey Marcy, member of the team that made the discovery, said that it is ‘heartwarming’ to find a planetary system that finally reminds of our solar system. The NASA scientists had noted that the two planets, one 2.5 times the size of Jupiter and the other three-quarters as large, orbit a star in the Big Dipper or Ursa Major constellation. Further, they informed that the star is about 51 light-years from Earth. 

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According to a press note released by NASA in 2001, Debra Fischer, a team member, had said, “Most of the 70 planets people have found to date are in bizarre solar systems, with short periods and eccentric orbits close to the star. As our sensitivity improves we are finally seeing planets with longer orbital period, planetary systems that look more like our solar system”. 

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51 light-years from Earth

The discovery of 74 Ursae Major was a part of the 100 other stars that the scientists had targeted since 1987. The NASA astronomers used the 3-meter and 0.6-meter telescopes at the University of California’s Lick Observatory to measure Doppler-shifted light reaching the Earth from stars. The NASA team noted regular changes in the Doppler shift which signal presence of a planet periodically pulling the star towards or away from Earth. 

Scientists back then had said that star is a yellow star similar to Sun and probably about seven billion years old, located about 51 light-years from Earth. Further, they, however, said that although 47 UMa has a planet similar to Jupiter in mass and orbital distance, there is no evidence that this star system also has an Earth-like planet. They added that the existence of two gas giant planets in orbit around 47 UMa makes it more difficult for such terrestrial planets to form within the star’s habitable zone.

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