from typing import Any
from warnings import warn
from numpy.random import Generator
from cratermaker.components.projectile import Projectile
from cratermaker.components.target import Target
from cratermaker.constants import FloatLike
[docs]
@Projectile.register("comets")
class CometProjectiles(Projectile):
_catalogue = {
"Mercury": 18400.0,
"Venus": 26300.0,
"Earth": 17670.0,
"Moon": 17670.0,
"Mars": 14210.0,
"Metis": 59000.0,
"Amalthea": 50000.0,
"Thebe": 45000.0,
"Io": 32000.0,
"Europa": 26000.0,
"Ganymede": 20000.0,
"Callisto": 15000.0,
"Himalia": 6100.0,
"Prometheus": 32000.0,
"Pandora": 31000.0,
"Epimetheus": 30000.0,
"Janus": 30000.0,
"Mimas": 27000.0,
"Enceladus": 24000.0,
"Tethys": 21000.0,
"Telesto": 21000.0,
"Calypso": 21000.0,
"Dione": 19000.0,
"Helene": 19000.0,
"Rhea": 16000.0,
"Titan": 10500.0,
"Hyperion": 9400.0,
"Iapetus": 6100.0,
"Phoebe": 3200.0,
"Cordelia": 20000.0,
"Ophelia": 19000.0,
"Bianca": 18000.0,
"Cressida": 18000.0,
"Desdemona": 18000.0,
"Juliet": 18000.0,
"Portia": 18000.0,
"Rosalind": 17000.0,
"Belinda": 16000.0,
"Puck": 15000.0,
"Miranda": 12500.0,
"Ariel": 10300.0,
"Umbriel": 8700.0,
"Titania": 6800.0,
"Oberon": 5900.0,
"Naiad": 22000.0,
"Thalassa": 22000.0,
"Despina": 21000.0,
"Galatea": 20000.0,
"Larissa": 18000.0,
"Proteus": 14000.0,
"Triton": 8200.0,
"Nereid": 2800.0,
"Pluto": 1900.0,
"Charon": 1800.0,
"KBO": 1800.0,
}
def __init__(
self,
sample: bool = True,
density: FloatLike | None = None,
angle: FloatLike | None = None,
direction: FloatLike | None = None,
location: tuple[FloatLike, FloatLike] | None = None,
target: Target | str | None = None,
rng: Generator | None = None,
rng_seed: int | None = None,
rng_state: dict | None = None,
**kwargs: Any,
):
"""
An operations class for computing the projectile properties of a comet source population.
Parameters
----------
sample : bool, default True
Flag that determines whether to sample impact velocities, angles, and directions from distributions. If set to False, the projectile velocity will be the mean velocity for the given target body.
density : float
The density of the projectile in kg/m³. Default is 500.0 kg/m³.
angle : float, optional
The impact angle in degrees. Default is 90.0 degrees (vertical impact) if `sample` is False. If `sample` is True, this value is ignored.
direction : float | None
The impact direction in degrees. Default is 0.0 degrees (due North) if `sample` is False. If `sample` is True, this value is ignored.`
location : tuple[float, float] | None
The impact location as a tuple of (longitude, latitude) in degrees. Default is (0.0, 0.0) (the equator and prime meridian) if `sample` is False. If `sample` is True, this value is ignored.
target : Target or str.
The name of the target body for the impact. Default is "Moon"
rng : Generator | None
|rng|
rng_seed : int | None
The random rng_seed for the simulation if rng is not provided. If None, a random rng_seed is used.
rng_state : dict, optional
|rng_state|
Notes
-----
The comets are assumed to be Jupiter-family Comets. The mean impact velocities for outer solar system bodies come from Table 1 of Zahnle et al. [#]_, and for inner solar system bodies, Table 2 of Borin et al. [#]_.
References
----------
.. [#] Zahnle, K., Schenk, P., Levison, H., Dones, L., 2003. Cratering rates in the outer Solar System. Icarus 163, 263-289. https://doi.org/10.1016/S0019-1035(03)00048-4
.. [#] Borin, P., Cremonese, G., Marzari, F., Lucchetti, A., 2017. Asteroidal and cometary dust flux in the inner solar system. A&A 605, A94. https://doi.org/10.1051/0004-6361/201730617
**kwargs : Any
|kwargs|
"""
density = 500.0 if density is None else density
kwargs.pop("mean_velocity", None)
kwargs.pop("velocity", None)
self._target = Target.maker(target, **kwargs)
mean_velocity = self._set_mean_velocity()
super().__init__(
sample=sample,
mean_velocity=mean_velocity,
velocity=mean_velocity,
angle=angle,
direction=direction,
location=location,
density=density,
target=target,
rng=rng,
rng_seed=rng_seed,
rng_state=rng_state,
**kwargs,
)
def __str__(self) -> str:
str_repr = super().__str__()
str_repr += f"Target: {self.target.name}\n"
return str_repr
def _set_mean_velocity(self):
"""
Sets the mean velocity of the projectile in m/s based on the target body.
Returns
-------
float
"""
if self.target.name in self.__class__._catalogue:
pmv = float(self.__class__._catalogue[self.target.name])
else:
warn(
f"Target {self.target.name} not found in known targets. Known targets include {list(self.__class__._catalogue.keys())}. Defaulting to KBO.",
stacklevel=2,
)
pmv = float(self.__class__._catalogue["KBO"])
return pmv
