2020RNAAS...4..197H

Wolf 1130 is a triple system containing an ultramassive white dwarf (Wolf 1130B), an M subdwarf (Wolf 1130A) and a T8 subdwarf (Wolf 1130C). We set out to determine a precise mass for Wolf 1130B by phase-folding TESS photometry to the previously reported orbital period. Each orbit was fit for ellipsoidal, Doppler beaming, and thermal photometric variability. We found that the measured beaming amplitude of Wolf 1130AB is nearly triple the theoretical expectation, which we assign to the short-wavelength filter cutoff of TESS and features in the M subdwarf spectrum. The photometric amplitudes suggest inflation of Wolf 1130A by as much as 20%, possibly due to its rapid rotation under tidal locking. TESS photometry can be used to obtain masses for short-period binary systems, but photometric precision limits the utility in the case of Wolf 1130AB.