Astrophiz 71 – John Sarkissian – SETI, PAFs & Cryogenics


Astrophiz 71: John Sarkissian ~ SETI, PAFs & Cryogenics
PLUS: ‘What’s up Doc’ reading from Dr @ianfmusgrave ’s Astroblog
Listen here:

This is the fourth of 6 ‘Astrotour’ episodes of Astrophiz, where we are publishing recordings of interviews I did on a two and a half thousand kilometre tour of five of Australia’s finest Eastern state radio and optical observatories.

Today’s feature interview is with John Sarkissian at the CSIRO Parkes Radio Observatory (Yes, he works with Dr Jane Kaczmarek who we featured in Episode 68)

John tells us how ‘The Dish’ is contracted to work on the Breakthrough Listen project to search for extraterrestrial intelligences. It’s a SETI project involving some of the world’s most powerful radio telescopes. He explains beautifully why and how cryogenics is incorporated into the Parkes and other dishes and how their next upgrade after the amazing UWL (ultra wide band) receiver will be the design, build and installation of PAFs (Phased Array Feeds)

In our regular segment for astrophotographers and observers, Dr Ian ‘Astroblog’ Musgrave usually presents ‘What’s Up Doc?’. However due to a bandwith fail on our Skype link, I read from his fabulous ‘Astroblog’. In this episode he tells us what to look for in the night sky and I give a brief report on viewing the Geminid Meteor shower that peaks on December 14.

In the News:

.1. Of course the big news is that two days ago NASA’s Insight Mission successfully landed on mars and will be drilling down to inject a seismograph 5m below the surface to study the interior of mars, Marsquakes and asteroid and meteor impacts. This research will inform all future missions to Mars in the future and tell us a lot about both Mars and Earth’s formation and geological history.

It was a sensational broadcast and was great to watch the landing live on NASA TV. 

So congrats to all the teams working on that project. The history of landings on Mars is a very chequered on. With more failures and successes by quite a number of space agencies, because Mars is a very difficult planet to land on. The atmosphere and gravity are markedly different than earths, so engineers can’t conclusively test their systems here on earth and all the more kudos to those who really understand the science and Maths that underpins these landings.

So what else is on Mars? InSight now, Curiosity and Opportunity Rovers of course (please phone home Oppy!)

In 2003 the European Space agency’s Mars Express Orbiter went into orbit and is still doing great science. Unfortunately the Beagle2 from that mission was one of the Mars casualties I mentioned earlier.

Also in orbit we have the 2001 NASA Mars Odyssey which has been there doing great work for 17 years now. 

Nasa’s Mars Reconnisance Orbiter has been up there since 2006.

In 2014 India’s ISRO Mars Orbiter Mission (MOM) was successful and the images coming back from its colour camera are stunningly beautiful apart from all the science they are doing there. Check them out. Well worth it.

The joint ESA/Roscosmos Trace Gas Orbiter went into orbit two years ago and a key goal of that project is to gain a better understanding of methane and other trace gases present in the Martian atmosphere that could be evidence for possible biological activity. The Trace Gas Orbiter delivered the Schiaparelli demonstration lander on 16 October 2016, which crashed on the surface. But they are optimistic that the lessons learned will spell success for the ExoMars Rover which is scheduled to land in 2020.

It’s a really busy place up there and as Richard Stevenson from the CSIRO/NASA CDSCC at Tidbinbilla says “It’s a real parking lot up there”

So we are looking forward to getting that data from InSight’s quakometers, and something else to look forward to is very soon we’ll be getting data back from the Parker Solar Probe.

There is so much going on, we cant possibly report on it all, but we’ll certainly be bringing you lots of highlights.

.2. Our final news story is about Barnard’s star and a possible exoplanet. This comes via Jonti Horner and Jake Clark from the University of Southern Queensland  reporting on a new paper published in the journal ‘Nature’.

The potential discovery of a planet orbiting Barnard’s Star – the second closest stellar system to the Sun – was announced by researchers today in Nature.

This discovery pushes the bounds of what we can do with our best current astronomical instrumentation, so the authors are understandably cautious in claiming a “planet candidate”, rather than a confirmed discovery. 

The new exoplanet (if it exists) is an icy world just over three times the mass of Earth, and has only been uncovered as a result of an exhaustive search by teams across the globe.

Shining 16 times too faintly to see with the unaided eye, Barnard’s Star is an ancient red dwarf – significantly older than the Sun. Aside from the Alpha Centauri system, it is the closest star to the Solar system. 

Barnard’s Star’s biggest claim to fame is the rate at which it is tearing across the night sky. It moves so rapidly against the background stars that it would cross the diameter of the full Moon in a little over 100 years.

In the middle of the last century, astronomer Peter van de Kamp was convinced Barnard’s star was accompanied by two Jupiter-mass planets. Over several decades, starting in the late 1930s, he studied the star, taking myriad images, and observing it moving against the background stars. 

Rather than moving in a straight line, his observations suggested Barnard’s Star was wobbling as it moved, rocking back and forth as though pulled by unseen companions. His data invoked the presence of two planets tugging the star around as it moved through space.

But despite their best efforts, astronomers elsewhere could find no evidence of van de Kamp’s worlds. Where his observations showed a wobbling star, theirs showed no such wobble – just a linear motion through space.

What was going on? van de Kamp’s observations were made using a large refracting telescope, and astronomers eventually realised that the telescope’s main objective lens had been cleaned and modified several times during the decades of his study. These changes caused the apparent position of the Barnard’s Star to shift back and forth relative to the bluer background stars.

The Jupiter-mass planets around Barnard’s star were no more.

Successive surveys ruled out ever smaller planets. Astronomers are now confident no planet larger than ten Earth masses exists in the system. Which brings us to our new find.

The new discovery:

The new candidate planet, Barnard’s Star b, is thought to have a mass between those of Earth and Neptune in the Solar system. While no such planet exists in our backyard, the Kepler spacecraft revealed that such planets are common in the cosmos.

Barnard’s Star b orbits its host at a distance of 60 million kilometres. That might suggest a warm, temperate world – but Barnard’s Star is a dim object, far less luminous than the Sun. As a result, Barnard’s Star b lies beyond what is known as the ice line, so far from the star that water would freeze harder than rock. This means it must be a frigid world.

Because Barnard’s star is so close, the separation between the planet and star in the sky will be relatively large. If the planet is really there, we will likely get our first direct images confirming its existence within the next ten years.

Beyond that? Who knows. One thing we have learned through the exoplanet era is that, where one planet lurks, more are sure to follow. If the existence of Barnard’s Star b is confirmed, it may indicate there are other, smaller worlds orbiting this ancient zippy star.

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