Saturday, March 20, 2021

Apollo Asteroid 2020 UQ6: A Super Fast Rotator

In the latest issue of Minor Planet Bulletin (VOLUME 48, NUMBER 2, A.D. 2021 APRIL-JUNE), our work on determining the rotation period of asteroid 2020 UQ6 was published. This  asteroid  is  a  Near-Earth  object belonging  to  the  Apollo  group  discovered  at  Tokyo-Kiso Observatory (MPC code 381) on 2020 October 27.


CCD photometric observation of 2020 UQ6 were carried  out  in 2×2 binned format during the night between 2020 October 28 and 29 by using the main telescope of the Osservatorio Salvatore di Giacomo,  Agerola  (MPC  code  L07).  It  is  a  0.50-m  Ritchey-Chretien operating at f/8 equipped with an unfiltered FLI-PL4240 CCD camera (2048×2048array of 13.5-micron pixels). 

The software Tycho by D. Parrott, that now offers the ability to construct lightcurves and determine rotation periods, was used during the observing session to extract the light curve of this interesting asteroid almost in real time.

In order to take in account both the high speed of the object (ranging from 21.48  arcec/min  to  17.46  arcsec/min  during  the  measurements) exposure times were kept to 4 s for all sessions. Eight  observation  sessions  collected  1373  data  points  for lightcurve analysis. This led to a bimodal lightcurve with a period of 0.04521 h (162.76 s), or a frequency of 530.84 rev/d, and an amplitude of 0.57 magnitudes. This finding identifies this object as a super-fast rotator asteroid (P << 2 h).

Credit: Guido et al.; MPB

From the absolute magnitude value  of H  =  22.6  and  assuming  the  asteroid  to  be  a  spherical object with a uniform surface and albedo ranging from 0.05 and 0.30, one can gets an estimated diameter ranging from 80 and 180 m.  From  this,  it  is  possible  to  add  the  average  value  of  the estimated diameter, D = 130 m, to the frequency vs diameter plot from  LCDB. As it can be observed, 2020 UQ6 is located in an uncrowded  region  of  the  graph  (identified  by  a  yellow  point), making this object particularly noteworthy. (click on the image below for a bigger version)

Credit: Guido et al.; MPB

by Ernesto Guido, Antonio Catapano, Alfonso Noschese, Antonio Vecchione

No comments: