Speaker
Description
We run a long-term project of time-resolved (lightcurve) photometric observations of near-Earth and main-belt asteroids. While our primary scientific interest is to determine other physical parameters of the studied objects (e.g., their spin rates and states, or binary nature), we also, as a by-product, obtain estimates of their absolute magnitudes. We run most of the observations at the 1.54-m Danish telescope on La Silla. The data are calibrated in the Johnson-Cousins VR photometric system using Landolt (1992) standards with the absolute accuracy 0.01 mag. The rotational brightness variations of the observed asteroids are removed by fitting Fouries series with their determined rotational periods, which results in determining their mean V and R magnitudes corresponding to the mean brightness. From the data, the mean (i.e., corresponding to the mean, “rotationally averaged” brightness) H = H_V or H_R of the studied asteroids are estimated. Uncertainties of the estimated absolute magnitudes are predominated by uncertainties of estimated or assumed (in cases where we do not have sufficient observational coverage in solar phase) slope parameters G and they range from ±0.02 to ±0.50 mag with a median of ±0.10 mag. Up to the date (2024-09-11) our sample is 544 H_V and 678 H_R values of NEAs and MBAs, covering a range of H from 8.52 to 30.24, with a median of 19.37. In the recent years, we determine on average 44 new H_V values per year, and we focus our recent efforts on sampling smaller NEAs with a median H around 21. As such, our data set is useful especially for characterizing the NEA population in the size range from 0.1 to 1 km, though the tail of the size distribution of our sample goes well below 100 m and so we obtain a limited characterization also for decameter-sized NEAs.
