You ever see the movie/ read the book "Sphere"? Basically that.

A Mathematician, as that will probably be the closest to a universal language.

An Astrophysicist to locate similar stars.

A Biologist (as well versed as possible in several disciplines) to try to understand their biological makeup.

A High ranking military official to secure any resources necessary to smooth over first contact.

And a Psychologist to help the team cope with the absolute madness/terror of witnessing something no living organism on this planet has ever experienced. Preferably a Behavorist to try and understand the behavioral patterns of the aliens.