Two Exoplanets Found Orbiting the Binary Star System, Kepler-47
This discovery was announced on August 28th, 2012, making it pretty recent! With the info I was able to glean from the above video, as well as a few articles on the topic, I have some things I would like to clarify and some additional info (and speculation) to contribute.
First off is that Kepler-47B is not in its stars’ “habitable zone,” so I don’t want to spend too much time talking about it. However, Kepler-47C IS in its stars’ “habitable zone” being only slightly closer to the binary system than Earth is from our Sun with an orbit of 303 days. Those of you that payed close attention to the video will recall that Kepler-47C is a gaseous giant, making it highly unlikely that life, as we know it, has developed there. This is where I would like to interject with a little bit of speculation.
Everything that I am reading about Kepler-47C says that the exoplanet is similar to Uranus or Neptune. We know that those planets are not habitable for a couple of reasons. Chief among those reasons:
- Their distance from their star and
- their gaseous form
We already know that Kepler-47C falls within the habitable zone, so the distance issue has been solved. However, there is still the gaseous form to contend with. We can’t do anything about that, but, what if Kepler-47C has a moon system? Both Uranus (stop giggling) and Neptune have rocky body moons, which means that it is possible that Kepler-47C does as well. If that is the case, their could be life there. As of yet, we don’t know if Kepler-47C has a moon system because it is too far away for us to observe that fact. The way the exoplanets were discovered was by measuring the variance in their stars’ brightness. Each time either of these exoplanets passes in front of their stars, we can measure a minute dip in the stars radiance. Also, while they are eclipsing their stars, we can use what we know about their stars and about how light interacts with given elements within a planet’s atmosphere to construct a likeness of that planet. This is how we know all that we do about these exoplanets. That being the case, it will be even more difficult to discover any moons these planets may have, as we have to use the same system to find them.
I do have a bit of speculation about the topic, so hang with me another minute. As I said, we aren’t sure if Kepler-47C has a moon system. What we can do is look at similar planets that we do know more about and extrapolate info from them. Let’s say, for just a minute, that Kepler-47C does have a moon orbiting it. We can look at the similarities between Kepler-47C and our very own Uranus and Neptune to see what kind of moon may exist in the shadow of Kepler-47C.
-Moons of Uranus-
The Uranus Moon System consists of 5 large moons and 22 small moons. The small moons aren’t large enough to speak of, so I’m going to focus on the large moons. These are in order of nearest the planet to furthest from the planet (with their diameters in parentheses)
- Miranda (~471.6 km)
- Ariel (~1,157.8 km)
- Umbriel (~1,169.4 km)
- Titania (~1,576.8 km)
- Oberon (~1,522.8 km)
If Kepler-47C were to have a moon similar to Uranus’ (stop giggling) moon Miranda , then the view of the night sky may look something like the view from Miranda, seen below.
- [Image]: Miranda; Uranus’ Nearest Moon with Uranus Looming in the Background (Click Image to Enlarge) [Credit]: Screen Cap from Solar Walk 3D for iPhone
-Moons of Neptune-
Neptune has a total of 13 moons, but only 2 that would be considered large moons when compared to Uranus’ Moon System. These are in order of nearest the planet to furthest from the planet (with their diameters in parentheses)
- Proteus (~420 km)
- Triton (~2,705.2 km)
Should Kepler-47C have a moon similar to Neptune’s Triton, the night sky might look a little like the night sky on Triton, seen below.
- [Image]: The view from Triton with Neptune and two of its other moons, Larissa and Proteus, clearly visible (Click Image to Enlarge) [Credit]: Screen cap from Solar Walk 3D for iPhone
To put all of these moons in perspective, our Moon is ~3,476.28 km meaning that Uranus’ Titania and Oberon are nearly half the size of our Moon and Neptune’s Triton is just over three-quarters the size of our Moon. This bit of speculation also assumes that Kepler-47C developed a multi moon system. Given the circumstances, it is possible that, rather than having multiple moons, those several bodies coalesced to form one large moon. Whether or not the planet has a ring system is also something that could affect our view of Kepler-47C possibly having a moon(s). The point of all this is to say that I am super excited to learn more about the Kepler-47 System as more info is found out and released in the future!
Posted on September 5, 2012, in Geek, Nerd, Science, Space and tagged albany, alloy matt, binary star, circumbinary planetary system, corvallis, exoplanets, geek, kepler-47, lebanon, matt jacobs, neptune, nerd, oregon, science, space, uranus. Bookmark the permalink. Leave a comment.