Posts Tagged ‘star’

by Robby Berman

All the scientific studies in the world of this one mysterious star have so far ruled out every theory except one, and it’s the wildest one. The whole thing started when Yale astronomer Tabetha Boyajian located star KIC 8462852, unofficially known as “Tabby’s star,” after Boyajian. Tabby’s star is doing something very strange.

In 2009, NASA launched its Kepler probe to keep a close watch on a small section of the sky — the idea was to learn more about a smaller area than less about a larger one. The probe tracks how light reflected from stars dims and grows brighter. Generally, when a star dims, a planet has passed in front of it, and will again and again as it travels its orbital path.

Kepler’s found some 2,000+ planets orbiting stars and published its data to allow citizen scientists to confirm their findings. A group of people affiliated with Yale called Planet Finders started going over the data, and Boyajian found her star.

To start with, it’s unexpectedly dim for a star of its its size and age. But what really got her attention was this chart.

Each vertical dip represents a holy-cow reduction in the star’s brightness, more than 10 times the dimming that astronomers would expect from a planet even as big as Jupiter crossing in front of the star. So it appears it’s not a planet causing Tabby’s star to dim, which is why it’s also called the “WTF star,” after the paper they published about it titled “Where’s the Flux?”

The data suggests something huge is orbiting the star, but what?

The reason the WTF star is famous is the hypothesis put forward to explain the dimming by Penn State astronomer Jason Wright: That what’s orbiting the star could be a “swarm of megastructures,” alien-built energy collectors, much like terrestrial solar panels. Wright told The Atlantic, “When Boyajian showed me the data, I was fascinated by how crazy it looked. Aliens should always be the very last hypothesis you consider, but this looked like something you would expect an alien civilization to build.” He was imagining something like a Dyson sphere.

Crazy, right? Well, since then scientists have been frantically pushing out other hypotheses to explain the anomaly.

Here are some of the more normal theories, and why they’re probably wrong:
•Kepler was malfunctioning — Nope.
•It’s a cloud of dust from star formation — But the star isn’t young. It shows no sign of the infrared light that indicates a new star.
•It’s a swarm of comets — But the dimming is too extreme to be caused by comets.
•It’s debris from colliding planets — But that matter would get sucked into the star so quickly it would be unlikely to linger long enough for us to see it.

http://bigthink.com/robby-berman/science-keeps-not-debunking-the-alien-dyson-sphere-idea?utm_source=Big+Think+Weekly+Newsletter+Subscribers&utm_campaign=344e51650c-Newsletter_081716&utm_medium=email&utm_term=0_6d098f42ff-344e51650c-41106061

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By James Griffiths

Astronomers have discovered a planet with three suns, where an observer would experience either constant daylight or triple sunrises and sunsets depending on the seasons, which last longer than a human lifetime.

The planet, HD 131399Ab, is the first discovered in a stable orbit in a triple-star system; previously, it had been assumed that the unstable gravity would result in any planet being quickly flung out.

“If the planet was further away from the most massive star in the system, it would be kicked out of the system,” Daniel Apai of the University of Arizona said in a statement.

“Our computer simulations have shown that this type of orbit can be stable, but if you change things around just a little bit, it can become unstable very quickly.”

Kevin Wagner, who discovered the planet and led follow-up observations, said that “for about half of the planet’s orbit, which lasts 550 Earth years, three stars are visible in the sky.”

“It is not clear how this planet ended up on its wide orbit in this extreme system, and we can’t say yet what this means for our broader understanding of the types of planetary systems, but it shows that there is more variety out there than many would have deemed possible.”

The planet — reminiscent of Luke Skywalker’s twin-starred homeworld of Tatooine in “Star Wars” — is located in the Centaurus constellation, about 320 light-years from Earth.

It was found using the SPHERE instrument on the European Southern Observatory’s Very Large Telescope, which is sensitive to infrared light, allowing it to detect the heat signatures of young planets.

About 16 million years old, HD 131399Ab is one of the youngest exoplanets discovered to date, the observatory said in a statement.

By comparison, Earth is about 4.5 billion years old.

With an average temperature of about 580 degrees Celsius (1,076 degrees Fahrenheit) and an estimated mass of four Jupiters, it is also one of the coldest and smallest directly imaged exoplanets.

“HD 131399Ab is one of the few exoplanets that have been directly imaged, and it’s the first one in such an interesting dynamical configuration,” Apai said.

http://www.cnn.com/2016/07/07/health/planet-orbits-three-suns/index.html