Presentation #438.02 in the session “Stellar Binaries 2”.
Using sparse radial velocities (RVs) from APOGEE (Holtzman et al. 2015, Jönsson et al. 2020) and an estimate of the photometric period from the All-Sky Automated Survey for SuperNovae (ASAS-SN, Shappee et al. 2014; Kochanek et al. 2017), Thompson et al. (2019) identified the first non-interacting black hole around a spotted red giant in the field. To identify similar binaries, we selected ~16,000 RV variables with ∆RVmax >1 km/s from APOGEE DR16 (Mazzola et al. 2020) where ∆RVmax is the maximum RV difference observed in APOGEE. We retrieved ASAS-SN V/g-band light curves and characterized the photometric variability of these sources using machine learning techniques (Jayasinghe et al. 2020). We selected spotted rotational variables with measured photometric periods from ASAS-SN that are (i) evolved red giants, (ii) not spectroscopic binaries (SB2s) in APOGEE, (iii) do not have an obvious blue excess and (iv) have large mass fractions, for further RV followup using the Keck HIRES and LBT PEPSI spectrographs. Here we report the first results of this expanded search.