Cut Timber

SpaceTime 20171229 Series 20 Episode 100 is out today

SpaceTime covers the latest news in astronomy & space sciences.

The show is available as a free twice weekly podcast through Apple Podcasts (itunes), Stitcher, Pocketcasts, SoundCloud, Bitez.com, YouTube, Audio Boom, your favourite podcast download provider, and from www.spacetimewithstuartgary.com

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Today’s stories…

NASA looking at missions to a comet and to Saturn’s moon Titan NASA has selected two finalist concepts for a robotic mission planned to launch in the mid-2020s. The agency is considering a comet sample return mission and a drone-like rotorcraft that would explore potential landing sites on Saturn’s largest moon, Titan.

Was the star of Bethlehem a real thing? For astronomy the idea of three wise men being guided by a star to a stable in a little town called Bethlehem two thousand years ago raises a number of problems. But let’s for a moment just suppose it really happened – So, what star were they following?

ET’s not calling Scientists say they’ve detected no alien signals or any evidence of extraterrestrial technology coming from the strange cigar shaped interstellar visitor which speed through our solar system in September and October. The 400 metre long 40 metre wide asteroid designated A/2017 U1 and named Oumuamua the Hawaiian name meaning “messenger” or “scout"— has been the centre of astronomical attention ever since its unexpected detection.

Skywatch January We turn our eyes to the skies and check out the celestial sphere for January on Skywatch with the Quadrantids meteor shower to light up the skies as well as another super moon and total lunar eclipse.

SpaceTime Background SpaceTime is Australia’s most respected astronomy and space science news program. The show reports on the latest stories and discoveries making news in astronomy, astrophysics, cosmology, planetary science, galactic and stellar evolution, physics, spaceflight, and general science. SpaceTime features interviews with leading Australian scientists about their latest research. The show is broadcast coast to coast across the United States by the National Science Foundation on Science360 Radio, and is available in Australia as a twice weekly podcast which averages over 3.5 million downloads annually. It’s hosted through AudioBoom and Bitez.com on all major podcast platforms. SpaceTime is also available as inflight entertainment on Virgin Australia Airlines, and on Tune in Radio. The SpaceTime program began life in 1995 as ‘StarStuff’ on ABC NewsRadio. Stuart Gary created the show while he was NewsRadio’s evening anchor and Science Editor. Gary wrote, produced and hosted the program, consistently achieving 9 percent of the Australian national radio audience share, according to Neilsen ratings survey figures for the five main metro markets (Sydney, Melbourne, Brisbane, Adelaide, & Perth). The StarStuff podcast was hosted by ABC Science on line, achieving over 1.3 million downloads annually. StarStuff was axed in 2015 following ABC funding cuts. Gary resigned from the ABC, taking the show with him and rebranding it as SpaceTime. The first SpaceTime episode was broadcast on February 8th 2016 and the show has been in production twice weekly ever since.

Front page post reminded me to upload my eclipse shot.

Alien megastructure not the cause of dimming of the ‘most mysterious star in the universe’

A team of more than 200 researchers, including Penn State Department of Astronomy and Astrophysics Assistant Professor Jason Wright and led by Louisiana State University’s Tabetha Boyajian, is one step closer to solving the mystery behind the “most mysterious star in the universe.”

KIC 8462852, or “Tabby’s Star,” nicknamed after Boyajian, is otherwise an ordinary star, about 50 percent bigger and 1,000 degrees hotter than the Sun, and about than 1,000 light years away. However, it has been inexplicably dimming and brightening sporadically like no other.

Several theories abound to explain the star’s unusual light patterns, including that an alien megastructure is orbiting the star.

The mystery of Tabby’s Star is so compelling that more than 1,700 people donated over $100,000 through a Kickstarter campaign in support of dedicated ground-based telescope time to observe and gather more data on the star through a network of telescopes around the world.

As a result, a body of data collected by Boyajian and colleagues in partnership with the Las Cumbres Observatory is now available in a new paper in The Astrophysical Journal Letters.

“We were hoping that once we finally caught a dip happening in real time we could see if the dips were the same depth at all wavelengths.

If they were nearly the same, this would suggest that the cause was something opaque, like an orbiting disk, planet, or star, or even large structures in space” said Wright, who is a co-author of the paper, titled “The First Post-Kepler Brightness Dips of KIC 8462852.” Instead, the team found that the star got much dimmer at some wavelengths than at others.

“Dust is most likely the reason why the star’s light appears to dim and brighten. The new data shows that different colors of light are being blocked at different intensities. Therefore, whatever is passing between us and the star is not opaque, as would be expected from a planet or alien megastructure,” Boyajian said.

The scientists closely observed the star through the Las Cumbres Observatory from March 2016 to December 2017. Beginning in May 2017 there were four distinct episodes when the star’s light dipped.

Supporters from the crowdfunding campaign nominated and voted to name these episodes. The first two dips were named Elsie and Celeste. The last two were named after ancient lost cities – Scotland’s Scara Brae and Cambodia’s Angkor. The authors write that in many ways what is happening with the star is like these lost cities.

The method in which this star is being studied – by gathering and analyzing a flood of data from a single target – signals a new era of astronomy. Citizen scientists sifting through massive amounts of data from the NASA Kepler mission were the ones to detect the star’s unusual behavior in the first place.

The main objective of the Kepler mission was to find planets, which it does by detecting the periodic dimming made from a planet moving in front of a star, and hence blocking out a tiny bit of starlight. The online citizen science group Planet Hunters was established so that volunteers could help to classify light curves from the Kepler mission and to search for such planets.

“If it wasn’t for people with an unbiased look on our universe, this unusual star would have been overlooked,” Boyajian said. “Again, without the public support for this dedicated observing run, we would not have this large amount of data.”

Now there are more answers to be found. “This latest research rules out alien megastructures, but it raises the plausibility of other phenomena being behind the dimming,” Wright said. “There are models involving circumstellar material – like exocomets, which were Boyajian’s team’s original hypothesis – which seem to be consistent with the data we have.”

Wright also points out that “some astronomers favor the idea that nothing is blocking the star – that it just gets dimmer on its own – and this also is consistent with this summer’s data.”

Boyajian said, “It’s exciting. I am so appreciative of all of the people who have contributed to this in the past year – the citizen scientists and professional astronomers. It’s quite humbling to have all of these people contributing in various ways to help figure it out.”

NGC 1275

EBLM J0555-57Ab is the smallest star ever known