SIMBAD references

The A1V star α Lacertae was observed by TESS in 2019 September and October. The short-cadence photometry reveals periodic variation at the 24.6 ppm level. The 0.708 day variation is consistent with rotational modulation seen in main sequence A stars, and implies an equatorial rotation velocity of 153 km s^–1. With prior spectroscopic measurement of the rotational broadening of 128 km s^–1, this indicates an inclination of the rotation axis of 57°. The first harmonic of this period is present in the data, along with a two non-commensurate periods of 0.763 and 0.257 day, suggesting spot modulation with different periods, perhaps indicating differential rotation with latitude. Follow-up spectroscopy and photometry of this bright (V = 3.77) star can place valuable constraints on differential rotation and spot formation and evolution in A stars.