BGLS-based method of estimating the rotational periods of asteroids

As the asteroid rotational period is important to the study of the properties of asteroids (e.g., super-fast rotators have structures owing an internal cohesion (rather than being rubble piles bounded by gravity only) so as not to fly apart), constructing an effective and fast method used to search the period attracts much researchers' attention. Recently, the Bayesian generalized Lomb-Scargle (BGLS) periodogram was developed to improve the convergence efficiency of the Lomb-Scargle method. However, the result of BGLS varies with the frequency range and cannot meet the two minimum/maximum requirements for a complete rotation of the asteroid. We propose a robust BGLS-based method that efficiently determines rotational periods. The proposed method employs a polynomial series to fit folded light curves with potential periods, initially calculated using the BGLS periodogram, and adopts a merit function to estimate and refine best-fit periods. We estimate the rotational periods of 30 asteroids applying the new method to light curves from the Palomar Transient Factory. Results confirm the effectiveness of the BGLS-based method in deriving rotational periods from ground-based observations of asteroids. Further application of the BGLS-based method to sparse light curves, such as Gaia data, is discussed.