Nine Bright gamma Doradus Variables Discovered with Ground-based Photometry

We have used precise photometric and high-dispersion spectroscopic observations to study nine candidate gamma Doradus (gamma Dor) stars, identified as optically variable comparison stars in our photometric studies of Sun-like stars. In this paper, we confirm these nine candidates as new gamma Dor variables. All exhibit sinusoidal variability with amplitudes between 6 and 65 mmag in Johnson B and periods from 0.28 to 1.13 days. All lie in the same region of the H-R diagram as our previously confirmed gamma Dor stars. Of the nine systems, one is a single-lined spectroscopic binary (SB1), two are double-lined spectroscopic binaries (SB2), and the remaining six are single stars. We present orbits for the three binary systems: HD 34415, HD 144839, and HD 182735. Their periods are 6400 days or 17.5 yr (adopted), 995 +/- 7 days, and 1052.4 +/- 0.2 days, respectively. We compare our photometric periods with those we derive for six of the nine stars observed with the Transiting Exoplanet Survey Satellite to strengthen the confirmation of these new gamma Dor variables. Finally, because the distribution of gamma Dor stars in the H-R diagram overlaps with the red edge of the delta Scuti (delta Sct) instability strip, we use our ground-based photometric results for the 73 gamma Dor stars confirmed with our Automatic Photoelectric Telescopes over the past two decades to look at the incidence of hybrid delta Sct/gamma Dor stars; these are highly valuable targets for asteroseismology.