Are you asking about PhD in Astrophysics because I have not found any course such as PhD in aero physics?. If we talk about PhD in astrophysics then the most basic eligibility criteria is to complete Master of Science in physics for Master of Science in Applied Physics. As you have done Master of Science in Physics then you are totally eligible for pursuing PhD in Astrophysics.

Other than this in your masters degree you must have completed and scored at least 55% to 60% marks in the aggregate of the examinations.

Read More about PhD.  Astrophysics by clicking on mentioned below link:

https://www.google.com/url?sa=t&source=web&rct=j&url=https://www.careers360.com/university/indian-institute-of-science-bangalore/phd-astronomy-and-astrophysics-course&ved=2ahUKEwjK3-b96a31AhUMq5QKHTV9DU4QFnoECAYQAQ&usg=AOvVaw0WZkyCRp7NnybFRi4r8Lw4

Hello there

The minimum eligibility criteria to do PhD in aerophysics is that you must have to qualify the master's degree in MSc/MSc integrated in Applied Physics ,Physics, astronomy ,electronics, photonics optics and integrated ME/M.

After completing your PhD degree in aerophysics you will become astrophysicist. And then later on you can join ISRO or any Research Institute or you can do post docs.

I hope it helps you!

Thank you!