Dr Tabetha Suzanne Boyajian (born c. 1980) is an American astronomer and astrophysicist on faculty at Louisiana State University. She was a post-doctoral fellow 2012–16 at Yale University, working with Debra Fischer. Boyajian is active in the astronomical fields of stellar interferometry, stellar spectroscopy, exoplanet research, and high angular resolution astronomy, all particularly at optical and infrared wavelengths. She was the lead author of the September 2015 paper "Where's the Flux?", which investigated the highly unusual light curve of KIC 8462852; the star is colloquially known as Tabby's Star in her honor.
Boyajian received a BS degree in Physics with concentration in Astronomy from the College of Charleston in 2003, an MS degree in Physics from Georgia State University in 2005, and a PhD degree in Philosophy of Astronomy from the same university in 2009. She studied the sizes of nearby stars similar to the Sun, using the University's CHARA array, a long-baseline optical and infrared interferometer located at Mount Wilson Observatory. Boyajian was awarded a Hubble Fellowship, and stayed at Georgia State University to study sizes of nearby stars much smaller than the Sun and stars with planets. Fellow astronomer Sarah Ballard has described this as "truly remarkable" work and has used what she calls this "precious sample" of data on nearby small stars for the "characterization by proxy" method to help investigate the far more distant exoplanet Kepler-61b.
Boyajian cowrote Extrasolar Planets and Their Host Stars in 2017 with Kaspar von Braun (von Braun & Boyajian 2017).
As of 2015, Boyajian is secretary and steering committee member of Division G Stars and Stellar Physics of the International Astronomical Union.
Boyajian is also manager of the Planet Hunters project in which amateurs analyze data from the Kepler space observatory.