Electronic Telegram No. 5005
Central Bureau for Astronomical Telegrams
Mailing address:  Hoffman Lab 209; Harvard University;
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Prepared using the Tamkin Foundation Computer Network


(248370) 2005 QN_173
     C. O. Chandler and C. A. Trujillo, Northern Arizona University; and H. H.
Hsieh, Planetary Science Institute, report the discovery of a second epoch of
activity (cf. CBETs 4995, 4998) for the active main-belt asteroid (248370),
which presented as a pronounced thin straight tail oriented in p.a. 251 +/-
1.4 degrees (in close agreement with the coincident anti-solar and anti-
motion vectors), with an observed angular extent of roughly 128",
corresponding to a length of 240000 km at that geocentric distance (r = 2.6
AU, phase angle 22.7 deg, true anomaly 56.5 deg; T = 2016 Jan. 2 with q = 2.4
AU), as seen in a public archival 89-s z-band image taken by D. Lang and A.
Walker using the Dark Energy Camera on the Blanco 4-m telescope at the Cerro
Tololo Interamerican Observatory on 2016 July 22 UT (astrometry tabulated
below).  This activity strongly suggests that the most probable driving
mechanism for the observed activity is sublimation (e.g., Hsieh et al. 2012,
Ap.J. 744, 9).

     2016 UT             R.A. (2000) Decl.
     July 22.43163    2 30 30.57   +14 47 53.2


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2021 July 26                     (CBET 5005)              Daniel W. E. Green