Skip to main content
`Ctrl`+`K`

# EclipsingSystem

class astroplan.EclipsingSystem(primary_eclipse_time, orbital_period, duration=None, name=None, eccentricity=None, argument_of_periapsis=None)

  Bases: `PeriodicEvent`

  Define parameters for an eclipsing system; useful for an eclipsing binary or transiting exoplanet.

  Warning

  There are currently two major caveats in the implementation of `EclipsingSystem`. The secondary eclipse time approximation is only accurate when the orbital eccentricity is small, and the eclipse times are computed without any barycentric corrections. The current implementation should only be used forapproximate mid-eclipse times for low eccentricity orbits, with event durations longer than the barycentric correction error (<=16 minutes).

  Parameters:
    primary_eclipse_time `Time`

      Time of primary eclipse

    orbital_period `Quantity`

      Orbital period of eclipsing system

    duration `Quantity` (optional)

      Duration of eclipse

    name str (optional)

      Name of target/event

    eccentricity float (optional)

      Orbital eccentricity. Default is `None`, which assumes circular orbit (e=0).

    argument_of_periapsis float (optional)

      Argument of periapsis for the eclipsing system, in radians. Default is `None`, which assumes pi/2.

  Methods Summary

  `in_primary_eclipse`(time) | Returns `True` when `time` is during a primary eclipse.
  `in_secondary_eclipse`(time) | Returns `True` when `time` is during a secondary eclipse
  `next_primary_eclipse_time`(time[, n_eclipses]) | Time of the next primary eclipse after `time`.
  `next_primary_ingress_egress_time`(time[, ...]) | Calculate the times of ingress and egress for the next `n_eclipses` primary eclipses after `time`
  `next_secondary_eclipse_time`(time[, n_eclipses]) | Time of the next secondary eclipse after `time`.
  `next_secondary_ingress_egress_time`(time[, ...]) | Calculate the times of ingress and egress for the next `n_eclipses` secondary eclipses after `time`
  `out_of_eclipse`(time) | Returns `True` when `time` is not during primary or secondary eclipse.

  Methods Documentation

  in_primary_eclipse(time)

    Returns `True` when `time` is during a primary eclipse.

    Warning

    Barycentric offsets are ignored in the current implementation.

    Parameters:
      time `Time`

        Time to evaluate

    Returns:
      in_eclipse `ndarray` or bool

        `True` if `time` is during primary eclipse

  in_secondary_eclipse(time)

    Returns `True` when `time` is during a secondary eclipse

    If the eccentricity of the eclipsing system is non-zero, then we compute the secondary eclipse time approximated to first order in eccentricity, as described in Winn (2010) Equation 33 [1]:

    The time between the primary eclipse and secondary eclipse \(\delta t_c\) is given by \(\delta t_c \approx 0.5 \left (\frac{4}{\pi} e \cos{\omega \right)\), where \(e\) is the orbital eccentricity and \(\omega\) is the angle of periapsis.

    Warning

    This approximation for the secondary eclipse time is only accurate when the orbital eccentricity is small; and barycentric offsets are ignored in the current implementation.

    Parameters:
      time `Time`

        Time to evaluate

    Returns:
      in_eclipse `ndarray` or bool

        `True` if `time` is during secondary eclipse

    References

    [1]

    Winn (2010) https://arxiv.org/abs/1001.2010

  next_primary_eclipse_time(time, n_eclipses=1)

    Time of the next primary eclipse after `time`.

    Warning

    Barycentric offsets are ignored in the current implementation.

    Parameters:
      time `Time`

        Find the next primary eclipse after `time`

      n_eclipses int (optional)

        Return the times of eclipse for the next `n_eclipses` after `time`. Default is 1.

    Returns:
      primary_eclipses `Time`

        Times of the next `n_eclipses` primary eclipses after `time`

  next_primary_ingress_egress_time(time, n_eclipses=1)

    Calculate the times of ingress and egress for the next `n_eclipses` primary eclipses after `time`

    Warning

    Barycentric offsets are ignored in the current implementation.

    Parameters:
      time `Time`

        Find the next primary ingress and egress after `time`

      n_eclipses int (optional)

        Return the times of eclipse for the next `n_eclipses` after `time`. Default is 1.

    Returns:
      primary_eclipses `Time` of shape (`n_eclipses`, 2)

        Times of ingress and egress for the next `n_eclipses` primary eclipses after `time`

  next_secondary_eclipse_time(time, n_eclipses=1)

    Time of the next secondary eclipse after `time`.

    Warning

    Barycentric offsets are ignored in the current implementation.

    Parameters:
      time `Time`

        Find the next secondary eclipse after `time`

      n_eclipses int (optional)

        Return the times of eclipse for the next `n_eclipses` after `time`. Default is 1.

    Returns:
      secondary_eclipses `Time`

        Times of the next `n_eclipses` secondary eclipses after `time`

  next_secondary_ingress_egress_time(time, n_eclipses=1)

    Calculate the times of ingress and egress for the next `n_eclipses` secondary eclipses after `time`

    Warning

    Barycentric offsets are ignored in the current implementation.

    Parameters:
      time `Time`

        Find the next secondary ingress and egress after `time`

      n_eclipses int (optional)

        Return the times of eclipse for the next `n_eclipses` after `time`. Default is 1.

    Returns:
      secondary_eclipses `Time` of shape (`n_eclipses`, 2)

        Times of ingress and egress for the next `n_eclipses` secondary eclipses after `time`.

  out_of_eclipse(time)

    Returns `True` when `time` is not during primary or secondary eclipse.

    Warning

    Barycentric offsets are ignored in the current implementation.

    Parameters:
      time `Time`

        Time to evaluate

    Returns:
      in_eclipse `ndarray` or bool

        `True` if `time` is not during primary or secondary eclipse