Planet of the Day: Kepler 186f

April 18, 2014

Great news, they found a 1.1 Earth mass planet orbiting in the habitable zone of a red dwarf star. Now, it isn’t the first Earth sized planet, but this one is in the habitable zone. There are other Earth sized planets going around the star too, four of them. They are all closer to the star, and not in the habitable zone. That we have found all those planets around the star is pretty great, though. Here is a great graphic of the planets and a great visual of how the transit method of planet searching works from io9:

 

Notice how the system is very compact, and how far away the fifth planet, 186f is compared to the other 4. Another fact of note is that the fifth planet orbits around 0.3-0.4 AU away from the star, which is similar to where Mercury is, or around one third the distance of the Earth from the sun. While that is still a huge distance, in terms of distances in our solar system, the planets are really close together.

Don’t assume, though, that it may be anything like the Earth. We don’t know its mass, so we don’t know the density, which means we don’t know what it is made of. We don’t know if it has surface waters or thick atmosphere or life. We don’t know anything except its size and period of the orbit, and size of the orbit. It is just a candidate planet and a neat discover. For more information, just go and read the links.

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Planet of the Day: Kepler 413b

February 9, 2014

This planet is a wild one. The planet has been found to precess  around 30 degrees in less than 11 years. Some of you may wonder what precession is. Well, basically it is the wobble of an object as it rotates. It happens to tops, and it does indeed happen on planet Earth too. There are various forms of precessions. The planet’s angle of rotation could change, which Kepler 413b does extremely quickly, and like the top, the axis of rotation itself could rotate in a circle. The planet Earth though, precesses so slowly that you need to wait thousands of years so you can even begin to see the change of the positions of the stars. Not in the case of this planet, wobbling without any stability.

There are also the orbital kind of precessions. Before going further, you should be aware that all orbits are ellipses, with the center of mass at a focus. Meaning, the orbits are not perfect circles, more like ovals, and the center of mass is not in the perfect center of the oval, but offset by a specific mathematical amount to a place called the focus. This means that in the case of orbital precession, the shape of the oval rotates around the focus itself over a large period of time. Mercury is famous for having a large orbital precession, caused by a combination of the gravitational pull of other Solar System objects and the mechanics of general relativity (aka the most accurate theory of gravity yet) itself.

The case of this planet is odd, though. When they first detected the planet by observing that the brightness of the star fell, signifying that the planet went in front of the star. They observed further cycles of the planet moving in front of the star. At one point, though, no object blocked the star’s light. And it kept going like this for many days until once again, they detected the same planet blocking the star’s light again and again. The significance of this discovery is compelling. It means the orbit is wobbling up and down, at times having the planet move in front of the star, at times above or below it.

The combination of all those factors would make seasonal changes of this planet extreme and unpredictable. As for what could have cause this? At this point, any theory about what happened would be speculation. We just don’t have enough data. The link itself gives plausible scenarios, though.

As for the physical characteristic itself, it is a gas giant. It is really close to its parent star, making its temperature very hot. It is 65 times the mass of the Earth, making it many times more massive than Neptune, but less massive than Saturn. While this goes in line with other gas giant discoveries, that its behavior deviates so much from what we have seen other planets do in their spin and orbit makes it a noteworthy object of study.


Good Kepler News

February 4, 2011

Firstly, the Kepler space telescope discovered a weird, compact planetary system composed of six planets, which you can read about it in here.

Secondly, and this is the best of all news, they have discovered over a thousand candidates of stars harboring planets. Over the next few years, expect the number of planets discovered to increase dramatically.

hat tip: badastronomy and io9


Do You Want to Hunt Planets?

February 2, 2011

Recently, I don’t know how long ago, though, the Zoo Universe project, which tries to involve citizens in helping out the professional astronomers sort through data, have added a new project to its list. It is called Planet Hunters. What it does is, it gathers the light curve data of stars (basically, the star’s brightness through time) from the space telescope Kepler and allows us to look at them. The basic premise is that stars have planets (well, duh), and some of those stars might have planets that orbit right in front of the star from our point of view. Those planets block some of the light from the star, thereby dimming it. By looking at the change in brightness in the curve, mainly the dipping of brightness at certain moments in time, one can detect planets, as shown in the picture below:

Of course, things aren’t as simple as that. As you will find out from checking out the web page and the tutorial, data is full of noise. The team behind this project, though, believe that because the human brain is so effective at noticing patterns, that we might be better at detecting these dips in between all of the noise than the machines. Maybe.

Anyways, go ahead and try! Who knows, maybe you might discover a planet.