We have a star having 1.8 solar mass. Justify any four means (measurable/ observed properties) by which you can identify that the object is a Pulsar and not a white dwarf or a Black Hole.
So one obvious property would be the mass. Since mass > 1.4 solar mass, we can say it is not a white dwarf.
Also the mass is less than 3 solar mass, hence its not a black hole (I'm speaking loosely over here).
Also from periodic radiation patterns, we can say that the object might be a pulsar.
I need help with 2 other means to categorize this object.