SIMBAD references

The epochs of 80 minima from 2019 to 2022 of the eclipsing binary BF Dra have been measured from photometric fluxes obtained by the TESS satellite with uncertainties of 3 s and 6 s for primary and secondary minima, respectively. There is a clear negative linear trend of the interval length between primary and secondary minima, which confirms previous analyses that the system's orbit has an apsidal motion. It is found that the periastron advances 1.43 ± 0.03 deg/century, i.e., the apsidal period is U = 25,200 ± 500 yr. These values agree with previous estimates within the combined uncertainties but the present uncertainties are lower by a factor of eight. It is also confirmed that the residuals of the TESS-minima have a significant trend relative to a mean long-term apsidal motion signature due to a systematic influence of unknown origin.