Thursday, December 22, 2011

Kepler - Bring on the world


Kepler-22b, 20e and f,
Out shone all the rest by being Earth-like the best.
Showing us transits that give us their size not their mass.
We can only guess that they aren’t all just gas.

Now 22b is in the goldilocks zone, 
meaning liquid water could make it a home.
But 20e and 20f are unlikely the best, 
to plan a voyage and settle down for a rest.
They orbit their star at a maddening pace, 
with three other planets joining in for the chase.
Each system is exciting, 
but we’d all like to know,
when Kepler will find us a place to call Home. 

Seager-MIT Physics department news
This is just a short poem about Kepler's earth-sized worlds I wrote when I could not sleep one night. Happy Holidays! 

Friday, December 16, 2011

The Good, The Bad, and The IDL


Astrophysics (fortunately or unfortunately) involves one form of coding or another. In my case that code is IDL. Now if you talk to certain people about different codes they become… let’s just say, passionate. I however am in the group that codes because they have to and learns the code that the person they work for uses, as they will hopefully know more than you do.

I am sad to say that in the month since I finished my literature review I have spent my days coding away in IDL. It is not all bad though, what I have found is that in writing a code or even looking up routines on the internet you learn a great deal about the process that reveal your results. 

The ‘beauty’ of coding it that when things are going well you feel like nothing can stop you, you have a clear plan and an end goal in mind. When things go bad, however, it feels like it will never work and you want to break down and cry right there at your desk. In this situation I suggest you swiftly put on something to hide the tears, I usually go with Stargate but the end scene from V for vendetta works wonders too! 

And remember Google is your friend!
 
A FEW CODING NOTES THAT I WOULD HAVE FOUND USEFUL!
 
;Finding the centroid of a star;
                Xcenter = TOTAL(TOTAL(array,2) * (INDGEN(length of  array)) / TOTAL(array)
                Ycenter = TOTAL(TOTAL(array,1) * (INDGEN(length of  array)) / TOTAL(array)
 
;Multiple line plots;
                Plot1 = PLOT(x, y, TITLE=’plot’, XTITLE=’x’, YTITLE=’y’, NAME=’array1’)
                Plot2 = PLOT(x2,y2, ‘green’, NAME=’array2’,  /OVERPLOT)
                Legend1 = LEGEND(TARGET=[plot1,plot2], POSITION=[0.75,0.75])

;Errorbars;
                errplot = ERRORPLOT(array, errarray, TITLE=’error plot’, XTITLE=’x’, YTITLE=’y’, ERRORBAR_COLOR=’red’)

Tuesday, December 6, 2011

Goldilocks' Porridge


Image from - Window to the universe
Just because it is in the goldilocks zone does not mean that the porridge won't kill you!

The habitable zone is named due to the fact that for life to exist, if there is a chance a planet will be inhabited, liquid water needs to be present. The habitable zone forms an annulus, donut shaped, region around a star, where water is condensed but not frozen so it is not too hot or cold.  This gives it the more popularized name, the 'goldilocks zone'.

Although the ability to harbour liquid water greatly increases the likelihood of life evolving on a planet it does not automatically mean any planet within this zone is habitable. This can even be seen within our own solar system, Venus is just inside and mars is just outside, the edges of our suns habitable zone. Yet the presence of life on mars seems to be in continuous debate with evidence that liquid water once flowed on the surface although it sits outside the habitable zone. At the other end of the scale it is clear that there is no chance of life on the surface of Venus, where temperatures soar due to the planet’s atmosphere causing the greenhouse effect trapping vast amounts of solar radiation (as well as high volcanic activity).

The recent announcement by the Kepler team of Kepler-22b has been hyped up in the media to be earths twin. Kepler-22b is the first planet in the Kepler list to have an orbit similar to that of earth around a very average sun like star. Its orbit is also keeps it within its stars habitable zone. Currently the published data for Kepler-22b states that the radius is 2.4 Re (2.4 times the radius of the Earth) with a temperature of around 22 degrees celcius. These values are still preliminary estimates and with no information on the massdensity and composition cannot be estimated.
Also as has been shown with other exoplanets, the radius varies with wavelength due to atmospheric absorption. Different chemical species in the atmosphere block out different portions of light at specific wavelengths. The different species will then have an effect on the temperature of the planet due to their interaction with stellar radiation, such as the greenhouse effect seen on earth and to a larger extent on Venus. Follow up observations of this planet have likely been bumped to the top of the list and with more data come more understanding (in most cases). It may be shown to have liquid water in the future but the atmosphere is the key.

So what I ask of the readers is that, although any planet in the habitable zone is likely to be very interesting to study, you should not assume life could ever exist there. Venus ('Earth's sister') is a habitable zone planet but I would hold off on booking a holiday visit.
 
I look forward to the many fascinating worlds that we will get to explore, albeit from afar, and hope to keep an open mind concerning habitable zone planets but will hold off until greater atmospheric data presents itself. 

Saturday, December 3, 2011

More planets than days


On December 1st 2011 the NASA Kepler planet finding mission celebrated its 1000th day in space and with over 1000 planetary candidates and 27 confirmed planets observed I would say that it was 1000 days’ worth celebrating. 

On March 6th 2009 Kepler was launched as NASA’s 10th Discovery mission. The mission was designed to survey our region of the galaxy to determine what fraction of stars have terrestrial-size planets in or near the habitable zone and for the last 1000 days it has been doing just that and more.

Kepler is a 0.95 meter telescope with a high precision photometer (light counter) which is able to continuously observe over 100,000 stars. Out of these stars the Kepler has discovered, 2165 eclipsing binaries, and 27 confirmed planets. Recently Kepler also released a list of 1235 planetary candidates so called as follow up observations need to be made to verify that they are in fact planets and not a result of other astrophysical phenomena. 

The illustration from the Kepler NASA website shows the expected size of these planetary candidates and their position in the field of view of the telescopes detectors. The aim of the mission is to put our solar system into context something which requires observations of the vast number of stars. Kepler provides a great opportunity for detailed photometric observations and although it is only looking at a very tiny portion of the sky the results thus far gives us great hope for finding an Earth like planet in the future. 

You too can help look for exoplanets http://www.planethunters.org/  is one of a number of outreach programs that uses the public to analyse scientific data as the collective human brain is a fantastic engine for pattern recognition. Who knows you could help find the next Earth-like exoplanet and the potential for life 
outside our own solar system. 

This week the first Kepler science conference is being held and a great number of new discoveriesrs are sure to be anounced as a result.
Kepler anounced a further 1094 bringing the total up to 2326 associated with 1792 stars in just 16 months!
Follow the progress - Kepler conference. There is also an informative press vidoe up on YouTube - NASA's Kepler Mission Announces Latest Planetary Discovery 


I will leave you with this quote from a very wise man.
“It is known that there is an infinite number of worlds, but that not every one is inhabited. Therefore, there must be a finite number of inhabited worlds. Any finite number divided by infinity is as near to nothing as makes no odds. So, if every planet in the universe has a population of zero, then the entire population of the universe must also be zero, and any people you may actually meet from time to time are merely the products of a deranged imagination” - Douglas Adams