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add star radius calculation based on stefan-boltzman law

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yuni 2024-04-19 03:39:12 +02:00
parent 70a602de5c
commit 8c0af0e467
1 changed files with 25 additions and 7 deletions
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32
doc/scripts/generate_starchart.py
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@ -34,7 +34,7 @@ MAX_APPARENT_MAGNITUDE = 7.0
SOL_ABSMAG = 4.83 SOL_ABSMAG = 4.83
SOL_RADIUS = 696.3e6 SOL_RADIUS = 696.3e6
SOL_LUMINOSITY = 3.828e26 SOL_LUMINOSITY = 3.828e26
STEFAN_BOLZMANN_CONSTANT = 5.670374419e-8 STEFAN_BOLTZMANN_CONSTANT = 5.670374419e-8
print("// This file was autogenerated by \"genrate_starchart.py\" using data from the") print("// This file was autogenerated by \"genrate_starchart.py\" using data from the")
print("// HYG database: https://github.com/astronexus/HYG-Database/tree/main/hyg") print("// HYG database: https://github.com/astronexus/HYG-Database/tree/main/hyg")
@ -43,7 +43,7 @@ print("// Each star's values: (x, y, z, magnitude, absolute magnitude, color ind
print("[") print("[")
def render(x, y, z, ra, dec, mag, absmag, ci, dist, name): def render(i, x, y, z, ra, dec, mag, absmag, ci, dist, name):
# Takes ra/deg in degrees # Takes ra/deg in degrees
ra = float(ra) ra = float(ra)
dec = float(dec) dec = float(dec)
@ -53,6 +53,8 @@ def render(x, y, z, ra, dec, mag, absmag, ci, dist, name):
if name == 'Sol': if name == 'Sol':
return return
#radius = star_radius(float(ci), float(absmag))
# distance = 1.0 # distance = 1.0
# ra_radians = math.radians(ra * 15) # ra is in [0, 24], multiplying by 15 gives degrees in [0, 360] # ra_radians = math.radians(ra * 15) # ra is in [0, 24], multiplying by 15 gives degrees in [0, 360]
# dec_radians = math.radians(dec) # dec_radians = math.radians(dec)
@ -73,17 +75,33 @@ def clean_name(string):
return "".join([c for c in string if c.isalnum() or c in ' -_']) return "".join([c for c in string if c.isalnum() or c in ' -_'])
def star_radius(color_index, absolute_magnitude):
# Convert color index to temperature (using Ballesteros' formula approximation for B-V)
temp = 4600 * ((1 / (0.92 * color_index + 1.7)) + (1 / (0.92 * color_index + 0.62)))
# Convert absolute magnitude to luminosity (in solar luminosities)
lum = 10 ** (0.4 * (SOL_ABSMAG - absolute_magnitude))
# Calculate the radius using Stefan-Boltzmann law (output should be in meters)
radius = math.sqrt(lum * SOL_LUMINOSITY / (4 * math.pi * STEFAN_BOLTZMANN_CONSTANT * temp ** 4)) # Luminosity in watts for the Sun ~ 3.828e26
# Convert radius from meters to solar radii (1 solar radius ≈ 6.96e8 meters)
radius_solar = radius / SOL_RADIUS
return radius_solar
total = 0 total = 0
count = 0 count = 0
count_extra = 0 count_extra = 0
entries = [] entries = []
with open(PATH, "r", encoding="utf-8") as f: with open(PATH, "r", encoding="utf-8") as f:
for entry in csv.DictReader(f): for index, entry in enumerate(csv.DictReader(f)):
entries.append(entry) entries.append((index, entry))
entries.sort(key=lambda entry: float(entry['mag'])) entries.sort(key=lambda entry: float(entry[1]['mag']))
for entry in entries: for index, entry in entries:
total += 1 total += 1
ra = entry['ra'] ra = entry['ra']
dec = entry['dec'] dec = entry['dec']
@ -104,7 +122,7 @@ for entry in entries:
continue continue
if float(mag) > MAX_APPARENT_MAGNITUDE: if float(mag) > MAX_APPARENT_MAGNITUDE:
continue continue
render(x, y, z, ra, dec, mag, absmag, ci, dist, name) render(index, x, y, z, ra, dec, mag, absmag, ci, dist, name)
count += 1 count += 1
#for entry in CUSTOM_ENTRIES: #for entry in CUSTOM_ENTRIES:
# render(entry[0], entry[1], entry[2], entry[3], entry[4]) # render(entry[0], entry[1], entry[2], entry[3], entry[4])