mga / hr_plot.py

## Dataset https://www.kaggle.com/datasets/konivat/hipparcos-star-catalog

import os import pandas as pd import numpy as np import matplotlib.pyplot as plt # Open the file "./hipparcos-voidmain.csv" for reading f = open("./hipparcos-voidmain.csv", "r") dataset = pd.read_csv(f, sep=",", header=0) # Get the data we want to plot # Apparent magnitude in the V band (visible light) apparentMag = np.array(dataset["Vmag"], dtype=float) # B-V color index bmv = np.array(dataset["B-V"], dtype=float) # Paralax paralax = np.array(dataset["Plx"].notna().notnull(), dtype=float) paralax = paralax[paralax > 0.1] # Compute distance only if parallax is not zero distance = 1000 / paralax # unit: parsec # Absolute magnitude absoluteMag = apparentMag - 5 * np.log10(distance / 10) # Plot the KDE of apparent magnitude, B-V color index, distance and absolute magnitude figure, axis = plt.subplots(2, 2, figsize=(10, 10)) axis[0, 0].set_title("KDE of apparent magnitude") axis[0, 0].set_xlabel("Apparent magnitude") axis[0, 0].set_ylabel("Density") axis[0, 1].set_title("KDE of B-V color index") axis[0, 1].set_xlabel("B-V color index") axis[0, 1].set_ylabel("Density") axis[1, 0].set_title("KDE of distance") axis[1, 0].set_xlabel("Distance") axis[1, 0].set_ylabel("Density") axis[1, 1].set_title("KDE of absolute magnitude") axis[1, 1].set_xlabel("Absolute magnitude") axis[1, 1].set_ylabel("Density") axis[0, 0].hist(apparentMag, bins=100, density=True) axis[0, 1].hist(bmv, bins=100, density=True) axis[1, 0].hist(paralax, bins=100, density=True) axis[1, 1].hist(absoluteMag, bins=100, density=True) plt.show() # Close the file f.close()

import os import pandas as pd import numpy as np import matplotlib.pyplot as plt import utilities # Open the file "/hipparcos-voidmain.csv" for reading f = open("./hipparcos-voidmain.csv", "r") dataset = pd.read_csv(f, sep=",", header=0) # Isolate the data we want to plot inputData = np.array(dataset[["B-V", "e_B-V", "Vmag", "Plx", "e_Plx"]], dtype=float) # Filter the data # Get rid of the NaN values inputData = inputData[~np.isnan(inputData).any(axis=1)] # Apply the following conditions: # - e_B-V should be smaller than 0.1 # - Plx should be larger than 0.1 # - e_Plx should be smaller than 5 inputData = inputData[(inputData[:, 1] < 0.1) & (inputData[:, 3] > 0.1) & (inputData[:, 4] < 5)] # Compute the distance distance = 1000 / inputData[:, 3] # unit: parsec # Compute the absolute magnitude absoluteMag = inputData[:, 2] - 5 * np.log10(distance / 10) bmv = inputData[:, 0] # Map B-V to RGB rgb = np.array([utilities.bv2rgb(item) for item in bmv]) # Plot the Hertzsprung-Russell diagram plt.figure(figsize=(10, 10)) plt.scatter(bmv, absoluteMag, s=0.05, c=rgb, alpha=0.75) plt.xlim(-0.5, 2.5) plt.ylim(-15, 15) plt.xlabel("B-V") plt.ylabel("Vmag") plt.title("Hertzsprung-Russell diagram") plt.gca().set_facecolor((0, 0, 0)) plt.gca().invert_yaxis() plt.show() # Close the file f.close()

import os import pandas as pd import numpy as np import matplotlib.pyplot as plt import utilities # Open the file "./hipparcos-voidmain.csv" for reading f = open("./hipparcos-voidmain.csv", "r") dataset = pd.read_csv(f, sep=",", header=0) # Get the position data x = np.array(dataset["RAdeg"], dtype=float) y = np.array(dataset["DEdeg"], dtype=float) # Get the magnitude data (will be use to determine the size of the point) apparentMag = np.array(dataset["Vmag"], dtype=float) # Convert apparentMag to size size = 10 ** (apparentMag / -2.5) # Get the color data (will be use to determine the color of the point) bmv = np.array(dataset["B-V"], dtype=float) # Map B-V to RGB rgb = np.array([utilities.bv2rgb(bv) for bv in bmv]) # Plot the stars position distribution plt.scatter(x, y, s=size, c=rgb, alpha=0.75) plt.title("Stars position") plt.xlabel("RAdeg") plt.ylabel("DEdeg") plt.gca().set_facecolor('black') plt.gca().invert_xaxis() plt.show() # Close the file f.close()

# Get the rgb color from B-V color # More info: https://wikipedia.org/wiki/Color_index # Function from https://stackoverflow.com/questions/21977786/star-b-v-color-index-to-apparent-rgb-color # By AymericG def bv2rgb(bv): if bv < -0.40: bv = -0.40 if bv > 2.00: bv = 2.00 r = 0.0 g = 0.0 b = 0.0 if -0.40 <= bv<0.00: t=(bv+0.40)/(0.00+0.40) r=0.61+(0.11*t)+(0.1*t*t) elif 0.00 <= bv<0.40: t=(bv-0.00)/(0.40-0.00) r=0.83+(0.17*t) elif 0.40 <= bv<2.10: t=(bv-0.40)/(2.10-0.40) r=1.00 if -0.40 <= bv<0.00: t=(bv+0.40)/(0.00+0.40) g=0.70+(0.07*t)+(0.1*t*t) elif 0.00 <= bv<0.40: t=(bv-0.00)/(0.40-0.00) g=0.87+(0.11*t) elif 0.40 <= bv<1.60: t=(bv-0.40)/(1.60-0.40) g=0.98-(0.16*t) elif 1.60 <= bv<2.00: t=(bv-1.60)/(2.00-1.60) g=0.82-(0.5*t*t) if -0.40 <= bv<0.40: t=(bv+0.40)/(0.40+0.40) b=1.00 elif 0.40 <= bv<1.50: t=(bv-0.40)/(1.50-0.40) b=1.00-(0.47*t)+(0.1*t*t) elif 1.50 <= bv<1.94: t=(bv-1.50)/(1.94-1.50) b=0.63-(0.6*t*t) return (r, g, b) # Get the temperature from B-V color # More info: https://wikipedia.org/wiki/Color_index def bv2temp(bv): temp=4600.0*(1.0/(0.92*bv+1.7)+1.0/(0.92*bv+0.62)) return temp