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2018-11-14. Super-Earth spied in the second-closest star system from the sun.

posted Nov 26, 2018, 8:04 AM by Alan Gould
By Daniel Clery, Science Magazine. [https://www.sciencemag.org/news/2018/11/super-earth-spied-second-closest-star-system-sun] For GSS A Changing Cosmos chapter 8. Excerpt: Our corner of the Milky Way is getting rather neighborly. In 2016, astronomers discovered a planet orbiting Proxima Centauri, the nearest star to our sun, just 4 light-years away. Now, they believe they have found an exoplanet around Barnard’s star, which at 6 light-years away is the second-closest star system. The planet—a chilly world more than three times heavier than Earth—is close enough that scientists could learn about its atmosphere with future giant telescopes. “This is going to be one of the best candidates,” says astronomer Nikku Madhusudhan of the University of Cambridge in the United Kingdom, who was not part of the discovery team. Barnard’s star b, as the new planet is called, was excruciatingly difficult to pin down, and the team is referring to it as a “candidate planet” though it is confident it’s there. ...Hundreds of exoplanets have been found by looking for periodic Doppler shifts in the frequency of starlight. In 2015, astronomers saw hints of such shifts in the light from Barnard’s star. “Then we went hard for it,” says astronomer Ignasi Ribas of the Institute of Space Sciences in Barcelona, Spain, who led the new project. His team made observations from two ground-based telescopes in Chile and Spain ...a spectrograph at Spain’s Calar Alto Observatory ...archival data spanning 20 years from those and four other instruments, ...a total of nearly 800 measurements. ...they found that the star’s light oscillated every 233 days, implying a planet orbiting with a 223-day year....