vendredi 5 janvier 2018

The mystery of the star of "Tabby" is solved












NASA - Kepler Space Telescope patch.

Jan. 5, 2018

Scientists have dismissed after months of work the thesis of an extraterrestrial structure to explain the light variations around "Tabby".


This image of KIC 8462852 is an artist illustration published by NASA. Image Credits: NASA/JPL-Caltech.

A fault?

The American astronomer Jason Wright, from Pennsylvania State University, caused a sensation in October 2015 by suggesting that this strange phenomenon could perhaps be explained by the presence of a sphere of Dyson, a megastructure built by an extraterrestrial civilization to capture the energy of the star. It took several months of observations for a team of more than 200 astrophysicists to reject this hypothesis. They now evoke clouds of dust.

Astronomer Jason Wright. Image Credit: Wikipedia

"Dust is the most likely cause of these variations in brightness of the star," says Tabetha Boyajian, assistant professor at Louisiana State University and principal author of this work published Wednesday in The Astrophysical Journal Letters.

http://iopscience.iop.org/article/10.3847/0004-637X/816/1/17

"The new data collected during the observations reveals different colors of light blocked at different intensities. This means that what passes between the star and us is not opaque, thereby removing an extraterrestrial megastructure or a planetary body, "said Ms. Boyajian, whose name inspired the nickname of the star, namely" Tabby 'but known scientifically as KIC 8462852.

About 50% larger than the Sun

This star, described by scientists as "the most mysterious of the universe", is located more than 1000 light-years from Earth. About 50% bigger than our Sun, it is also 1000 degrees warmer.

Even though scientists have dismissed the hypothesis of a giant extraterrestrial structure, "the last observations could also be the signature of other natural phenomena," points out Wright, who participated in this study. "There are mathematical models simulating circumstellar materials like exocometes, orbiting a star, which seems to correspond to the data we have collected," he says.

Kickstarter campaign

Tabby was discovered with the Kepler space telescope, developed by NASA and dedicated to the detection of exoplanets when they pass their star and momentarily reduce their brightness.

More than 1,700 people donated a total of $ 100,000 to the Kickstarter crowdfunding platform to further explore this star. Astronomers at the observatory in Las Cumbres, California, have studied it closely between March 2016 and December 2017.

Related articles:

An alien star in distant space seems to be acting very strangely
http://orbiterchspacenews.blogspot.ch/2015/10/an-alien-star-in-distant-space-seems-to.html

Star Strange Likely Swarmed by Comets
http://orbiterchspacenews.blogspot.ch/2015/11/strange-star-likely-swarmed-by-comets.html

The Scientific Quest to Explain Kepler's Most Enigmatic Find
http://orbiterchspacenews.blogspot.ch/2017/10/the-scientific-quest-to-explain-keplers.html

Mysterious Dimming of Tabby 's Star May Be Caused by Dust
http://orbiterchspacenews.blogspot.ch/2017/10/mysterious-dimming-of-tabbys-star-may.html

Related links:

NASA's Kepler Space Telescope: http://kepler.nasa.gov/

NASA's Spitzer Space Telescope: https://www.nasa.gov/spitzer

Planet Hunters: http://www.planethunters.org/

Images (mentioned), Text, Credits: AFP / Orbiter.ch Aerospace / Roland Berga.

Best regards, Orbiter.ch

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