Thursday, February 2, 2017

Comets & Asteroids - Summary for December 2016

During the month of December 2016, 1 new comet has been discovered. "Current comet magnitudes" & "Daily updated asteroid flybys" pages are available at the top of this blog (or just click on the underline text here).  

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

- Comet Discoveries

Dec 21  Discovery of C/2016 X1 (LEMMON)

- Other news

Dec 13 Image of the Kuiper belt object Orcus and its moon Vanth posted on twitter by M. Brown: "The ALMA radio telescope/interferometer detects the heat coming from Orcus ~4 billion miles away and separately from its moon Vanth."

Credit: ALMA - M. Brown

Dec 20 Man-To Hui & David Jewitt published on Arxiv the follwing paper "Non-Gravitational Acceleration of the Active Asteroids" where they present an astrometric investigation of 18 active asteroids in search of non-gravitational acceleration. "Comets can exhibit non-gravitational accelerations caused by recoil forces due to anisotropic mass loss. So might active asteroids."

Dec 23 CBET 4339 reports that a group of observers obtained lightcurves of the minor planet (12008) KANDRUP  during July 2007, which were typical of binary synchronous asteroids. "The period is around 1.371 day.  "The monitoring until January 2008 showed a regular evolution of the signature of mutual phenomenona.  Other observations were obtained between August and October 2010, showing lightcurves with similar properties.  In December 2013, the amplitude of variation was similar to those of the other oppositions, but some events were possibly missed.  As observed on 2016 Dec. 2 and 7, the mutual phenomenona are 0.5-magnitude deep and their duration is around 4 hours; an observed brightness minimum occurred on Dec. 6.930 UT.  These are indications that the mutual orbit of the system components is close to the ecliptic plane, like that of minor planet (4492) Debussy". 

Dec 26 Vera Rubin, American astronomer, passed away (July 23, 1928 – December 26, 2016). Her work on galaxy rotation rates led to theory of dark matter.

Rubin looking through a telescope. Credit: Vassar College, courtesy AIP Emilio Segrè Visual Archives

by Ernesto Guido