Bulgarian scientist Vesselin Kostov is part of a NASA team that has discovered a planet orbiting two suns. Astronomers from Goddard Space Flight Center at NASA and Diego State University have discovered the largest planet outside our solar system, orbiting two stars at a distance that could allow for life to exist. However, exoplanet "Kepler-1647b" is the size of Jupiter and is a gas giant, which makes it unsuitable for life. The discovery was announced at a conference of the American Astronomical Society in San Diego, California, the BGNES agency reported. Vesselin Kostov is a PhD in astrophysics. He graduated in physics from the Sofia University and then continued his studies in the faculties of physics and astronomy at the University of Oklahoma and the Johns Hopkins University. He also worked for the Lamont-Dohety Earth Observatory at Columbia University before starting work for NASA.