Exoplanet Explorer: V2.0.0 arrives
So, what’s new?
Probably the most important change in this release is that the app can now automatically update its database whenever new planets are discovered. The data for this is created by a tool I developed and then sent to my server where the app can download it. Downloading is disabled by default, but you can activate in the options menu, after which it will check for new data every time you start the app. The update procedure should be pretty quick as it only downloads the changes and then modifies the database that ships with the app to bring it up to date.
Another improvement is the inclusion of binary star systems! This turned out to be a lot more work than I thought it would be because I was unable to find a comprehensive online source that provides enough information about the component stars in a binary system to be able to estimate their orbits. Most binaries start off being identified as a single star, before further research reveals that there’s more than one body and most/all online references (including the Encyclopaedia) include the stats for the original discovery when it was thought to be a single star. Currently, there’s seven binaries identified in the app, and a further 19 that the data extraction tool thinks are possible binaries but have been left as solitary stars due to lack of data.
There’s a lot more stats filled with this release. The source of the data is the Exoplanet Encyclopaedia which is missing data for a lot of stars and planets, mainly because there’s no single location to get all the data, so it is collected from various sources all of which have some info. Because of this, I invested a lot of time in modifying my data extractor to calculate and estimate missing values. When this wasn’t enough, I then went and filled in the data manually. There’s still a handful of stars and planets missing enough data to create them, amongst which are the majority of the WASP systems.
Because of the increased time and maintenance required for the new release, and the bandwidth costs for providing the data updates, the app’s price has had to increase a little, to about US$2.99.
Other changes include :
- Rreferences to “stars” now reading “systems” which was necessary for to be able to display binary systems.
- Navigation between stars is now smoother thanks to code borrowed from Solar Explorer.
- An on-screen keyboard for entering planet and star names when filtering.
- New preset searches and more sort ordering for finding things like binary systems
- Planet temperatures and last update date are also included now
You’ll probably spot a new “Optional Extras” item in the options menu which is intended to add a miscellaneous list of enhancements to planets and stars when viewed close up. Starting with this release, enabling the option will add a ring system to a random selection of gas giants in other systems The reason I’ve added this is that 100% of the gas giants in our Solar System feature ring systems composed of rock, dust and ice, though only Saturn’s and Uranus’ are easily visible. I wouldn’t be surprised to find out that planetary ring systems are common, especially around planets with large masses and moons. The app won’t feature rings around hot jovian or hot neptunian worlds because I would expect that high temperatures and solar winds would evaporate ring material and blow it away. Even rock will evaporate at a high enough temperature.
Another notable change is that stars are now sized more accurately, though if you try to zoom in to one of the few pulsars in the app, you’ll find that you can’t actually get very close. This isn’t just to protect you from the intense gravitational field, it is also caused by the fact that these objects are so tiny, about 24km/15mi across, that due to the scale of the typical solar systems, the 3D engine can’t render objects so small when they are close to the camera. To actually make them visible, I’ve had to set it up so that the camera stays back.
A few weeks ago, while I was working on this update, the media was running stories about the first Earth sized planets discovered. You’ll find that if you visit Kepler-20 e and Kepler-20 f that they will actually be classed as super-terran and neptunian respectively. The reason for this is that Exoplanet Explorer uses a mass classification system based on the maximum estimated mass for a planet, which puts these planets at 3 times and 14 times the mass of Earth, whereas the media used the radius estimates which estimates their size as similar to our home world. Hopefully NASA will be able to improve the accuracy of their mass estimates in future and that they will show that the mass of these worlds is close to ours so that they will end up in the Earth category at a later date.
There’s a minor glitch that affects a handful of systems that have planets that orbit incredibly close to their parent stars. In these rare cases, the planets will actually end up in side the star, which usually isn’t the case in the real world. There’s also one instance of a jovian world orbiting a pulsar which has the pulsar inside the planet. This is caused by the scaling of the system to fit it on screen and the extreme size differential between two bodies that are orbiting ridiculously close to each other. I’ve got a solution in mind, but I decided to do the release since 99% of systems look OK and I didn’t want to delay any longer.
There’s also a few instances of habitable zones that don’t look right, particularly around binary systems. In general, the binary systems that have been discovered so far won’t have a habitable zone at all, so I’m contemplating disabling habitable zones for binaries until I can implement a better function to calculate zones for these sorts of stars. I also want to recheck the figures for the stars in the binary systems because I’m not 100% sure the orbits are right. If I find any problems, a minor data update should be all that’s needed to fix it.
The final issue is one that affects some Tegra 2 tabs running Android 3 when the Detailed Planets option is enabled. I’ve been informed by the developer of the tool I use that they’ve found the problem and I’m just waiting on them to release the fix. When it arrives, I’ll do a quick update to V2.0.1, and release a similar update for Solar Explorer since it is also affected.
As always, report any issues here on my blog as I generally can’t help if you post on Android Market because I can’t contact you with a solution, or ask for more information.