coPsi#
Stellar rotation, inclination, and orientation
coPsi is made to derive stellar rotation periods from photometric light curves, then properly calculate the stellar inclination, and ultimately measure the obliquity \(\psi\) through:
\[\cos \psi = \sin i_\star \sin i_{\rm o} \cos \lambda + \cos i_\star \cos i_{\rm o} \, ,\]
where \(i_\star\) is the stellar inclination, \(i_{\rm o}\) is the orbital inclination, and \(\lambda\) is the projected obliquity.
References