Pandas Planets - Add calculated column, remove / delete column (drop)

import pandas as pd

df = pd.read_csv('planets.csv')

print(df.head())
print()

df['dm'] = df['Distance (AU)'] * df['Mass']
print(df.head())
print()

df.drop(columns = 'Mass', inplace=True)
print(df.head())

Output:

  Planet name  Distance (AU)     Mass
0     Mercury           0.40  0.05500
1       Venus           0.70  0.81500
2       Earth           1.00  1.00000
3        Mars           1.50  0.10700
4       Ceres           2.77  0.00015

  Planet name  Distance (AU)     Mass        dm
0     Mercury           0.40  0.05500  0.022000
1       Venus           0.70  0.81500  0.570500
2       Earth           1.00  1.00000  1.000000
3        Mars           1.50  0.10700  0.160500
4       Ceres           2.77  0.00015  0.000415

  Planet name  Distance (AU)        dm
0     Mercury           0.40  0.022000
1       Venus           0.70  0.570500
2       Earth           1.00  1.000000
3        Mars           1.50  0.160500
4       Ceres           2.77  0.000415