exoMAST_API

Python wrapper for exo.mast.stsci.edu/api

Object oriented python wrapper based on the API provided by exo.mast.stsci.edu/api with stellar documentation provided here: https://exo.mast.stsci.edu/docs/

This python wrapper accesses the exo.mast.stsci.edu api (v0.1) in order to access both the currated planet information and any other data access (e.g. spectra, file listings, time series) that are provided by mast, now via a python wrapper.

I use the code primarily to access exoplanet system parameters as inputs to any transit light curve fitting tools. I would imagine that RV curve fitting models would also benefit from the background database access.

I owe great thanks for helping to develop this API to documentation and conversations with the exo.MAST team and, especially, Dr. Susan Mullally!

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Here is a nominal layout for usage:

Resolving Exoplanets

import exomast_api
planet_name = 'HD 189733 b'
exoplanet = exomast_api.exoMAST_API(planet_name, quickstart=True)

Setting quickstart=True (the default behaviour) automatically runs self.get_identifiers() or self.get_properties(); this is the base operation of our Python API: to "get the identifiers and properties" from exoMAST and load them into Python.

Setting quickstart=False is useful if the user has already downloaded the json file from exo.mast.stsci.edu and stored it locally.

For example:

wget -c -O hd187733b_identifiers.json https://exo.mast.stsci.edu/api/v0.1/exoplanets/identifiers/?name=HD189733b
wget -c -O hd187733b_properties.json https://exo.mast.stsci.edu/api/v0.1/exoplanets/HD%20189733%20b/properties

After the downloads are complete, open ipython and continue this example

from exomast_api import exoMAST_API
exoplanet = exoMAST_API('HD 189733 b', quickstart=False)
exoplanet.get_identifiers(jsonfile='hd187733b_identifiers.json')
exoplanet.get_properties(jsonfile='hd187733b_properties.json')

Either which way, we can now look at what data is available

print(f'Planet Name: {exoplanet.planet_name}')
print(f'Rp/Rs: {exoplanet.Rp_Rs}')
print(f'a/Rs: {exoplanet.a_Rs}'.format())
print(f'Orbital Period: {exoplanet.orbital_period}')
print(f'Transit Center Time: {exoplanet.transit_time}')
print(f'Eccentricity: {exoplanet.eccentricity}')
print(f'Argument of Periastron: {exoplanet.omega}')

There are also dictionaries containing all of the information accessed from the STScI exo.MAST API.

for key,val in exoplanet._planet_ident_dict.items():
    print('{:15}{}'.format(key,val))

for key,val in exoplanet._planet_property_dict.items():
    print('{:25}{}'.format(key,val))

Detrended Flux Time Series Data Queries

If the target has a KIC (Kepler) or (soon-to-be) TIC (TESS) id, then the api can access the more specific information; such as

Listing TCEs

List all of the available TCEs for this star: considerations apply for multiple transiting system

These can be accesses from exomast_api (here) as

exoplanet.get_tce()
print('TCEs Available: {}'.format(exoplanet.tce))

Metatdata queries

Provide extensive information about this KIC/TIC system This operation will acquire 'DV Primary Header' and 'DV Data Header' information

exoplanet.get_planet_metadata()
for key0 in exoplanet._planet_metadata_dict.keys():
    print('\n\n{}\n'.format(key0))
    for key,val in exoplanet._planet_metadata_dict[key0].items():
        print('{:12}{}'.format(key,val))

Data queries

Acquire the detrended light curves for either a KIC or a TIC This provides 2 entries in the dictionary exoplanet._planet_table, which can be viewed as:

exoplanet.get_planet_table()
print('\n\nFields:\n'.format(key0))
for val in exoplanet._planet_table['fields']:
    print('{:12}{:13}{}'.format(val['colname'], val['datatype'], val['description']))

print(type(exoplanet._planet_table['data']))
for key,val in exoplanet._planet_table['data'][0].items():
    print('{:12}{}'.format(key,val))