Exoplanets as Table

Turn the data from the open exoplanet catalog into a lua table.

Why though

Lua is pretty neat (or, in my opinion better to use than python) but working with XML directly in it is not pretty neat. Being able to use the data as a table should make it much easier to do whatever you want with it. If you also want a library to help with using the data, there's torch, scilua, and I'm sure plenty more.

Dependencies

• xml
• lfs
• serpent

Using

Assuming lua and all this programs dependencies are installed you only need to run lua build.lua. However, I didn't like how the catalog's XML translated into a table, so you can also run it with the -f or --fix argument to change varaiable names to camelCase and have all arrays of objects (stars, binaries, and planets) become direct children of their system. Here's a list of the allowed arguments

• -i ./path/to/data/folder or --input ./path/to/data/folder sets the data input directory
• -o ./path/to/output/file.lua or --output ./path/to/output/file.lua sets the table output directory
• -f or --fix cleans up, reparents data, and removes some fields like videolink and description
• -m or --minify makes the ouput table smaller, but also less readable

Where do I get the data from?

The open exoplanet catalog. Put the two folders "systems" and "systems_kepler" into a directory and point build.lua to that directory with the -i argument.

Data Structure

Assuming you don't use the -f argument, this will be the exact same as what's listed here, otherwise it'll follow this slightly modified version.

Key	Can be child of	Description	Unit
planets	system	This is an array for all the planets in a system. A planet is a free floating (orphan) planet if there are no other stars, binaries, or planets in this system.
stars	system	This is an array for all the stars in a system. A star can be host to one or more planets (circum-stellar planets).
binaries	system	This is an array of binaries. A binary consists of either two stars, one star and one binary or two binaries. In addition a binary can be host to one or more planets (circum-binary planets).
declination	system	Declination	+/- dd mm ss
rightAscension	system	Right ascension	hh mm ss
distance	system	Distance from the Sun	parsec
name	system, binary, star, planet	Name of this object. This tag can be used multiple times if the object has multiple Names.
semimajorAis	binary, planet	Semi-major axis of a planet (heliocentric coordinates) if child of planet. Semi-major axis of the binary if child of binary.	AU
separation	binary, planet	Projected separation of planet from its host, or if child of binary the projected separation from one component to the other. This tag can occur multiple times with different units. It is different from the tag semimajoraxis as it does not imply a specific orbital configuration.	AU, arcsec
positionAngle	binary	Position angle	degree
eccentricity	binary, planet	Eccentricity
periastron	binary, planet	Longitude of periastron	degree
longitude	binary, planet	Mean longitude at a given Epoch (same for all planets in one system)	degree
meanAnomaly	binary, planet	Mean anomaly at a given Epoch (same for all planets in one system)	degree
ascendingNode	binary, planet	Longitude of the ascending node	degree
inclination	binary, planet	Inclination of the orbit	degree
impactParameter	planet	Impact parameter of transit
epoch	system	Epoch for the orbital elements	BJD
period	binary, planet	Orbital period	day
transitTime	binary, planet	Time of the center of a transit	BJD
periastronTime	binary, planet	Time of periastron	BJD
maximumRVTime	binary, planet	Time of maximum radial velocity	BJD
mass	planet, star	Mass (or m sin(i) for radial velocity planets)	Jupiter masses (planet), Solar masses (star)
radius	planet, star	Physical radius	Jupiter radii (planet), Solar radii (star)
temperature	planet, star	Temperature (surface or equilibrium)	Kelvin
age	planet, star	Age	Gyr
metallicity	star	Stellar metallicity	log, relative to solar
spectralType	star, planet	Spectral type
magB	binary, star, planet	B magnitude
magV	binary, star, planet	Visual magnitude
magR	binary, star, planet	R magnitude
magI	binary, star, planet	I magnitude
magJ	binary, star, planet	J magnitude
magH	binary, star, planet	H magnitude
magK	binary, star, planet	K magnitude
discoveryMethod	planet	Discovery method of the planet. For example: timing, RV, transit, imaging.
isTransiting	planet	Whether the planet is transiting (1) or not (0).
discoveryYear	planet	Year of the planet's discovery	yyyy
lastUpdate	planet	Date of the last (non-trivial) update	yy/mm/dd
spinOrbitAlignment	planet	Rossiter-McLaughlin Effect.	degree

TODO

• One object can have multiple names, so that should be an array instead of just one value
• Make sure all file's being parsed are XML (have .xml extension at the least)