Could One Be Krypton? Two Newly-Discovered Exoplanets Orbiting Red Star Raise New Questions

Thursday, 20 June 2019 - 4:18PM
NASA
Alien Life
Thursday, 20 June 2019 - 4:18PM
Could One Be Krypton? Two Newly-Discovered Exoplanets Orbiting Red Star Raise New Questions
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Image Credit: Composite – Pixabay/Stefans02 via Flickr CC BY 2.0
Two alien worlds identical to Earth in mass and composition have just been discovered orbiting the habitable zone of a peaceful star twelve short light-years away. It has been all but confirmed as the closest star to Earth with more than one planet in the habitable zone. The study was published in Astronomy & Astrophysics, an international journal.


Teegarden's star is an 8 billion-year-old red dwarf in the constellation Aries, but it's dim and emits most energy in infrared – scientists didn't even notice it until approximately 2002-2003. The star numbered among a group of 342 that scientists were searching for orbiting planets, and scientists very nearly didn't find them.


Because of their extreme distance, exoplanets are usually discovered by measuring the effect their orbits have on the host star. This is tricky because red dwarf stars like Teegarden's are known for their volatility: sometimes it's hard to know whether the data indicates a violent stellar flare, or evidence for the home of our future alien overlords coming into view. Scientists took over two hundred measurements, and the star's oddly quiet nature made it easy to separate planetary wheat from stellar chaff. "I would bet both my little fingers that they are there," bragged Ignasi Ribas, a member of the Institute of Space Studies of Catalonia who participated in the study.


The two planets – Teegarden b and Teegarden c – are approximately as close to their host star as Mars and Earth are to the Sun, each with a mass about 1.1 times that of Earth. Teagarden b is the closer of the two and has the highest Earth Similarity Index discovered in a planet to date. Researchers estimate a 60% chance of Teegarden b having a temperate surface climate, assuming there's an atmosphere similar to Earth. The odds don't look nearly as promising for Teegarden c, which scientists give a 3% change of balmy temperatures. They're both close enough to their host star to have liquid water, however.


More data needs to be gathered before we can pop the Champagne to celebrate an interstellar summer home. Chiefly, how fast the star rotates on its axis and more accurate measurements of how quickly these two planets complete their respective orbits. Moreover, just because Teegarden's star is quiet now doesn't mean it was always so calm. A volatile period prior to its discovery could have stripped these planets of their atmospheres and rendered them uninhabitable.


Ribas doesn't let those possibilities dampen his enthusiasm. "We will eventually see if they are actually habitable and, perhaps, even inhabited."



Image Credit: Composite – Pixabay/Stefans02 via Flickr CC BY 2.0


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