January 9, 2017 marks the 25th anniversary of Exoplanet discovery. On this day in 1992 the science journal Nature published a paper by astronomers Alex Wolszczan and Dale Frail detailing first confirmation of planets orbiting a star beyond our solar system. That star was a pulsar, 2300 light years away in the constellation Virgo, known as PSR B127+12. Pulsars are maelstroms of fast spinning highly magnetized solar remnants created when mass at the moment of supernova isn’t enough to make a black hole. Instead the outer layer blasts to oblivion, leaving an inner core of dense material exerting unimaginable gravitational force. Spinning countless times per second, those maintaining angular momentum become pulsars – distinguished by intense beams of radio emissions several times a second, similar to a lighthouse beacon.
At Arecibo Observatory in Puerto Rico Frail and Wolszczan witnessed regular dimming of the pulsar beacon, split second interruptions caused by orbiting planets. Two planets, PSR1257+12b (orbiting once every 66 days) and PSR1257+12c (one orbit every 98 days) became our first proven exoplanets. In 1994 they discovered PSR1257+12d, a tiny third exoplanet orbiting once every 25 days.
In 2015 the International Astronomical Union sponsored a Name Exoworlds contest, 12b, c and d became Draugr, Poltergeist and Phobetor. In 2009 NASA launched the Kepler Space Telescope using the same method of light interruption to detect planetary orbits. To date Kepler has identified 2330 of the over 3500 confirmed exoplanets. Happy exoplanet anniversary,