About HD 184840
HD 184840 is a common star. It lies about 492.7 light-years from Earth, sits in the constellation Sgr, shines at apparent magnitude 7.56 and has spectral type A5V+....
Its spectrum reads A5V+... — an A-type star: white-hot, typically about twice the Sun's mass, and the class most of the sky's famous bright stars belong to.