Tce
- class exovetter.tce.Tce(*args, **kwargs)[source]
Bases:
dict
Class to handle Threshold Crossing Event (TCE).
It inherits from
dict
and defines a list of reserved keywords inrequired_quantities
, which must containQuantity
. Other keys in the dictionary have no restrictions.By requiring that certain measured properties have units attached, it reduces the risk of modeling a transit with data in the wrong units; e.g., entering the transit duration in hours but treating the value as if it is the duration in days. It also allows depth given in parts per million to be used correctly in places that expect depth to be in fractional amplitude.
This class also handles the problem with transit times given in different zeropoints. Most transit data has times corrected to the barycentre of the solar system and expressed in the unit of days since some zeropoint. However, there is no agreement on the zeropoint. Some data is given in Julian Date, while other missions choose mission specific zeropoints; e.g.,
t=0
for Kepler data corresponds to a Barycentric Julian Date (BJD) of 2454833. This problem is addressed here by requiring epoch and period data to beQuantity
and by providing aget_epoch()
method.- Raises:
- KeyError
Required quantities missing, causing
validate()
to fail.
- Attributes:
- required_quantitiesset
Keys in which their values must be
Quantity
.
Attributes Summary
Methods Summary
from_json
(filename)Read a json file and populate a TCE object
get_epoch
([offset])Get the epoch of the transit in the desired BJD-based time system.
to_json
(filename)Write a json file with standard file name
validate
()Check that required quantities are present.
Attributes Documentation
- required_quantities = {'depth', 'duration', 'epoch', 'epoch_offset', 'period'}
Methods Documentation
- classmethod from_json(filename)[source]
Read a json file and populate a TCE object
- Parameters:
- filenamestring
Filename of json file containing tce informamtion
- Returns:
- None.
- get_epoch(offset=None)[source]
Get the epoch of the transit in the desired BJD-based time system.
The time of first transit of your TCE is stored as a date offset from BJD=0 by an amount given by
offset
(e.g., BKJD, TJD). This method converts the time of the first transit to a time offset from the epoch desired.- Parameters:
- offset
Quantity
The epoch offset desired. Some pre-defined offsets are available in
exovetter.const
. For example, the time of first transit inbkjd
.
- offset
- Returns:
- epoch
Quantity
Epoch of the transit in the desired BJD-based time system.
- epoch
- Raises:
- KeyError
Calculation failed due to missing keys.