Exoplanet Explorer: Working towards version 2.0
Today marks a milestone working towards the next release of Exoplanet Explorer, version 2.0, with the completion of what is probably the hardest part: the new planet database and extraction script.
The old one used the same layout that the Exoplanet Encyclopaedia uses, which is what’s called a one-to-one relationship, where each planet is associated with a single star.
In the real world, some planets orbit more than one star. A handful of these have been flagged in the Encyclopaedia with the code “(AB)” as part of the name, meaning that the “star” has an A and a B component, in other words, it’s a binary system with two stars.
There’s more than a handful of binary systems with known planets though. According to my efforts over the last week, I’d estimate that of the 580 or so systems with planets, at least 25 actually have more than one star and that’s not counting the planets which orbit stars that are themselves orbiting other stars.
With this in mind, I went back to the drawing board and completely rewrote the script that constructs the database. The new format will allow Exoplanet Explorer to handle systems with more than one star in them.
I’ve also upgraded the script so that it will fill in as much data as possible whenever it finds missing values, meaning that a lot more more systems will be approximated. It also notes all the calculations and estimates it performs, which will be displayed, so that you won’t have to wonder what’s estimated or calculated and what came from Simbad or the Encyclopaedia.
As a final step, I’ve also gone through the stars that were missing one or two values and, wherever possible, looked up figures from scientific journals. This was a real pain because there’s just not much data on many of the binary stars, in particular the variety known as cataclysmic binaries which are basically a white dwarf star and an M class star orbiting each other. Luckily, these guys are pretty predictable so it’s not too hard to make some basic estimates. One thing I won’t have to worry about with cataclysmic binaries is working out a habitable zone as the white dwarf star’s gravitational field is gradually consuming the M class star, releasing high levels of radiation, hence the name cataclysmic.
The database script should now be able to construct complete models for about 90% of the systems known to have planets.
I had hoped to get all the changes in this release done while science took a holiday, but alas, discovering new planets is apparently more interesting than wrapping presents during the consumer festival known as Christmas.
Today’s announcement of two actual Earth sized planets in a new system is great, but unfortunately the app is in a state where I can’t build a release, so you won’t be able to see it until version 2.0 hits the market, which is a shame as the hot Terran model is already in the app that you’ve got.
Luckily, this won’t be an issue for much longer as in addition to the new database in v2.0, the app will be able to update the data without having to download a new version.
This also means that the price of Exoplanet Explorer will have to rise a little because this website will be providing the data for free, so bandwidth has to be paid for and besides that, the new database has to be maintained on a regular basis. My script does most of the work, but I’ll still periodically scan the list looking for scraps of data on planets to make it more complete for you.
If you want to avoid the price rise, then now is the time to pick up the full version of Exoplanet Explorer before V2.0 arrives.
Oh, and Exoplanet Explorer v2.0 will be appearing on SlideMe market too for those of you who don’t have access to (or hate) Android Market.