Predisintegration study of comet C/2021 A1 (Leonard).

GARCÍA, R.S.; FERNÁNDEZ LAJÚS E.; DI SISTO R.P.; GIL-HUTTON, R.A.

Congreso; XVII Latin American Regional IAU Meeting; 2023

Comet C/2021 A1 (Leonard) was discovered on January 2021 with a magnitude of V ≈ 19 at an heliocentric distance rH = 5 au . Leonard is an hyperbolic comet reaching perihelion in January 2022which achieved visibility with the naked eye in late 2021 and then showed spectacular gas and dusttails. However, Leonard became photometrically unstable in December 2021 and January 2022 when its morphology has changed, getting diffuse and with the tail becoming more relevant on January 22, 2022 at rH ≈ 0.74 au. In a previous paper images of the Leonard disruption were presented estimating that the complete disintegration of the nucleus was near mid-December, 2021 explaining that the rotational instability driven by out-gassing torques offers the most plausible mechanism for the disruption. In this poster we present images of this comet on the broadband B, V, and R filters taken with the 0.6 m HSH telescope in CASLEO, Argentina on December 21 and 22, 2021; close to the estimated date of the disruption event. Our goal is to study the comet dust behavior in the previous moments to the disintegration event.