Comets & Asteroids - Summary for July 2017

During the month of July 2017, 2 new comets were discovered and cometary activity was detected for 1 previously discovered object (earlier designated as an asteroid). "Current comet magnitudes" & "Daily updated asteroid flybys" pages are available at the top of this blog (or just click on the underline text here). See below for the "Other news" section.

The dates below refer to the date of issuance of CBET (Central Bureau Electronic Telegram)  which reported the official news & designations.

- Comet Discoveries

Jul 01 Discovery of C/2017 M5 (TOTAS)

Jul 24 Discovery of C/2017 O1 *

* Note on CBET 4426 issued on August 26: After considerable discussion, the IAU "Working Group for Small Body Nomenclature" (formerly the IAU "Committee for Small Body Nomenclature" and the IAU "Small Bodies Names Committee") has decided to accept the name "ASASSN" for comet C/2017 O1 (cf. CBET 4414).

- Cometary activity detected

Jul 03 Cometary activity detected in Hilda-type minor planet (457175) 2008 GO_98 *

* The following permanent number has been assigned on CBET 4442 issued on October 09: 362P/(457175)P/2008 GO_98

- Other news

Jul 5 CBET 4412 reports that minor planet (7344) SUMMERFIELD is a binary system with an orbital period of 17.41 +/- 0.01 hr.  The primary shows a period of 2.58975 +/- 0.00003 hr and has a lightcurve amplitude of 0.17 mag at solar phases 9-15 degrees, suggesting a nearly spheroidal shape.  Mutual eclipse/occultation events that are 0.03- to 0.07-magnitude deep indicate a secondary-to-primary mean-diameter ratio of 0.18 +/- 0.03.  The mean absolute R magnitude in the Cousins system is H_R = 12.88 +/- 0.08, assuming the phase relation slope parameter G = 0.24 +/- 0.11.

Jul 07  New paper on Arxiv by Kokotanekova et al.: "Rotation of Cometary Nuclei: New Lightcurves and an Update of the Ensemble Properties of Jupiter-Family Comets"

Credit: Kokotanekova et al

Jul 12 CBET 4413 report the discovery of an apparent satellite (S/2017 (113) 1) of minor planet (113) Amalthea from observations made of the Tycho Catalogue star 1878-01081-1 (magnitude V = 10.0) during an occultation by the minor planet (which was at V = 12.9) on 2017 Mar. 14.167 UT.  A total of ten observation sites recorded seven positive events and three negative events for (113), two of which are attributed to the possible satellite.

Credit: IOTA / Brad Timerson

by Ernesto Guido