LOCATION, ORBIT AND ENERGY OF A METEOROID IMPACTING THE MOON DURING THE LUNAR ECLIPSE OF JANUARY 21, 2019 & TESTING THE WEAK EQUIVALENCE PRINCIPLE WITH COSMOLOGICAL GAMMA RAY BURSTS

Location, orbit and energy of a meteoroid impacting the moon during the Lunar Eclipse of January 21, 2019 During the total lunar eclipse of January 21, 2019 at least two meteoroids impacted the moon producing visible flash lights on the near side. One of the impacts occurred on the darkest side of the visible lunar face and was witnessed by many astrophotographers. In this paper we present estimations of the location, impact parameters (velocity and incoming direction), orbit and energy of the meteoroid, as obtained from images and videos collected by amateur astronomers in Colombia, the Dominican Republic, Morocco, USA, Canary Islands, Cape Verde, Czech Republic, Austria, and Germany. Astrometric measurements on the images put the impact location at selenographic lat = -29.43 and lon = -67.89 while photometric measurements predict the flash brightness of Gf = 6.7. The novel Gravitational Ray Tracing (GRT) technique is used to estimate the orbital properties and radiant of the impactor. We find that that the meteoroid impacted the moon with a speed of 13.8 km/s (70% C.L.) and in a relatively shallow angle, (6 of visible light in a short time (0.3 seconds). The total impact energy was ~0.5 tons of TNT which correspond to a body with a mass ~20 kg and a diameter of ~30 cm. If our assumptions are correct, the crater left by the impact will have ~10 meters across and it could be detectable by prospecting lunar probes. These results arose from a timely collaboration between professional and amateur astronomers which highlight the importance of citizen science in contemporary astronomy. Testing the Weak Equivalence Principle with Cosmological Gamma Ray Bursts Gamma Ray Bursts (GRBs) with rapid variations at cosmological distances are used to place new limits on violations of the gravitational weak equivalence principle (WEP). These limits track intrinsic timing deviations between GRB photons of different energies as they cross the universe, in particular in the KeV to GeV energy range. Previous limits in this energy range have involved only the gravitational potential of local sources and utilized temporal variability on the order of 0.1 seconds. Here WEP violation limits are derived from sources with greater distance, faster variability, and larger intervening mass. Specifically, GRB sources with redshifts as high as 6.5 are considered, with variability as fast 0.2 milliseconds, and passing the gravitational potentials of inferred clusters of galaxies distributed randomly around the line of sight. WEP violation limits are derived from data from GRB 910711, GRB 920229, GRB 021206, GRB 051221, GRB 090429, and GRB 090510. The strongest constraint in the very early universe comes from GRB 090429 which limits gamma (500 keV) - gamma(250 keV) \u3c 1.2 x 10-13. The strongest overall constraint comes from GRB 090510 which yields a WEP violation limit of gamma(30 GeV) - gamma (1 GeV) \u3c 6.6 x 10-16. This strongest constraint is not only a new record for WEP violation limit for gamma-ray photons and in the early universe, but the strongest upper bound for Delta gamma that has ever been recorded between any two energy bands

Location, orbit and energy of a meteoroid impacting the moon during the Lunar Eclipse of January 21, 2019

During lunar eclipse of January 21, 2019 a meteoroid impacted the Moon producing a visible light flash. The impact was witnessed by casual observers offering an opportunity to study the phenomenon from multiple geographical locations. We use images and videos collected by observers in 7 countries to estimate the location, impact parameters (speed and incoming direction) and energy of the meteoroid. Using parallax, we achieve determining the impact location at lat. $-29.43^{+0.30}_{-0.21}$, lon. $-67.89^{+0.07}_{-0.09}$ and geocentric distance as 356553 km. After devising and applying a photo-metric procedure for measuring flash standard magnitudes in multiple RGB images having different exposure times, we found that the flash, had an average G-magnitude $\langle G\rangle = 6.7\pm0.3$. We use gravitational ray tracing (GRT) to estimate the orbital properties and likely radiant of the impactor. We find that the meteoroid impacted the moon with a speed of $14^{+7}_{-6}$ km/s (70% C.L.) and at a shallow angle, $\theta < 38.2$ degrees. Assuming a normal error for our estimated flash brightness, educated priors for the luminous efficiency and object density, and using the GRT-computed probability distributions of impact speed and incoming directions, we calculate posterior probability distributions for the kinetic energy (median $K_{\rm med}$ = 0.8 kton), body mass ($M_{\rm med}$ = 27 kg) and diameter ($d_{\rm med}$ = 29 cm), and crater size ($D_{\rm med}$ = 9 m). If our assumptions are correct, the crater left by the impact could be detectable by prospecting lunar probes. These results arose from a timely collaboration between professional and amateur astronomers which highlight the potential importance of citizen science in astronomy.Comment: 19 pages, 11 figures, 4 tables. Data and scripts available in https://github.com/seap-udea/MoonFlashes. Accepted for publication in MNRA