Find habitable zone boundaries

Compute habitable zone (HZ) boundary orbital distances in AU as a function of stellar mass and age using mors.aOrbHZ.

Prerequisites

Make sure the package and stellar evolution data are installed:

pip install fwl-mors
mors download all

Step 1: Compute HZ boundaries for a single stellar mass

By default, aOrbHZ uses stellar parameters at 5000 Myr if Age is not specified:

import mors

hz = mors.aOrbHZ(Mstar=1.0)

The returned dictionary contains six boundary distances:

for key, val in hz.items():
    print(f"{key}: {val:.4f} AU")

Step 2: Specify a stellar age

import mors

hz = mors.aOrbHZ(Mstar=1.0, Age=1000.0)  # 1 Gyr
print(hz["HZ"])

Step 3: Compute HZ boundaries for multiple masses

Pass an array of masses to get arrays back in the dictionary:

import numpy as np
import mors

masses = np.array([0.3, 0.5, 0.8, 1.0])
hz = mors.aOrbHZ(Mstar=masses, Age=5000.0)

print(hz["HZ"])               # array of HZ midpoints in AU
print(hz["RunawayGreenhouse"])

Step 4: Access HZ boundaries from a Star object

When a Star is created, HZ boundaries are automatically computed and stored as star.aOrbHZ:

import mors

star = mors.Star(Mstar=1.0, Omega=1.0)
print(star.aOrbHZ["HZ"])
print(star.aOrbHZ["MoistGreenhouse"])

Common pitfalls

• Age is in Myr, not years or Gyr.
• The HZ key is the midpoint of MoistGreenhouse and MaximumGreenhouse, not RunawayGreenhouse.
• When passing an array for Mstar, each value in the returned dictionary is an array of the same length.