Thursday, February 28, 2019

Comets & Asteroids - Summary for Nov & Dec 2018

During the 2-month period November through December 2018, 10 new comets were discovered, cometary activity was detected for 1 previously discovered object (earlier designated as asteroids) and there was 1 comet recovery. Moreover an apparently asteroidal object with nearly-parabolic orbital elements was discovered. No cometary activity has yet been confirmed, but it has been given a cometary style A/ designation. "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

Nov 08 Discovery of C/2018 V1 (MACHHOLZ-FUJIKAWA-IWAMOTO)     (CBET 4569 & 4572)
Nov 18 Discovery of P/2018 VN_2 (LEONARD)            (CBET 4573)*
Nov 20 Discovery of C/2018 U1 (LEMMON)                 (CBET 4574)
Dec 01 Discovery of C/2018 V2 (ATLAS)                       (CBET 4578)
Dec 01 Discovery of C/2018 V4 (AFRICANO)               (CBET 4579)
Dec 03 Discovery of C/2018 W1 (CATALINA)               (CBET 4580 & 4582)**
Dec 03 Discovery of C/2018 W2 (AFRICANO)              (CBET 4580)***
Dec 16 Discovery of C/2018 X2 (FITZSIMMONS)        (CBET 4583)
Dec 17 Discovery of C/2018 X3 (PANSTARRS)             (CBET 4584)
Dec 20 Discovery of C/2018 Y1 (IWAMOTO)                (CBET 4588)

* MPC inadvertently assigned it the minor-planet designation 2018 VN_2 by mistake.

** No cometary activity was detected at discovery, but it was given a cometary style A/ designation. On December 16, CBET 4582 reported that a faint coma had been detected in images taken with the CFHT at Mauna Kea on December 8.

*** Nearly simultaneous independent discoveries of a comet were reported on Nov. 27 via CCD images taken by H. Groeller (with the Catalina Sky Survey 0.68-m Schmidt telescope) and by B. M. Africano (with the Mount Lemmon 1.5-m reflector). G. V. Williams notes that Africano reported the object first, and that the object was posted on the Minor Planet Center's NEOCP webpage before Groeller's report arrived.  The Central Bureau received Africano's report at around Nov. 27.55 UT, or 21 minutes before Groeller's report was received.

- Cometary activity detected

Nov 29 Cometary activity detected in 2017 TW_13 =  P/2017 TW_13 (LEMMON)  (CBET 4576)

- Comet Recoveries

Dec 06  Recovery of P/2005 GF_8 (LONEOS) as C/2018 X1 (CBET 4581)

According to CBET 4579 (Dec. 01, 2018), an apparently asteroidal object designated A/2018 V3 with nearly-parabolic orbital elements (T = 2019 Sept. 8.66 TT, e = 0.990, q = 1.34 AU; at mag 21 and about 4 AU from the sun) was discovered. No cometary activity has yet been confirmed, but it has been given a cometary style A/ designation.


Further to CBET 4442, the following permanent numbers have been assigned to short-period comets based upon their being securely observed at multiple returns to perihelion.
Designation/Name         Provisional Designations                Reference
363P/Lemmon               P/2011 VJ_5 = P/2017 W1               CBET 4455
364P/PANSTARRS        P/2013 CU_129 = P/2018 A2           CBET 4475
365P/PANSTARRS        P/2011 WG_113 = P/2017 U6          CBET 4490
366P/Spacewatch          P/2005 JN = P/2018 F2                    CBET 4497
367P/Catalina                P/2011 CR_42 = P/2018 H1             CBET 4510

368P/NEAT                   P/2005 R1 = P/2018 L3                      CBET 4526
369P/Hill                       P/2010 A1 = P/2018 P1                      CBET 4538
370P/NEAT                   P/2001 T3 = P/2018 P2                      CBET 4539
371P/LINEAR-Skiff         P/2001 R6 = P/2018 R1                      CBET 4552
372P/McNaught             P/2008 O2 = P/2018 P6                      CBET 4554

373P/Rinner                  P/2011 W2 = P/2018 R2                     CBET 4555
374P/Larson                  P/2007 V1 = P/2018 S1                      CBET 4558
375P/Hill                       P/2006 D1 = P/2018 T1                     CBET 4560

- Other news
Nov 08 CBET 4570, CBET 4575 (Nov 27), CBET 4586 (Nov 18) report that the following minor planets are binaries systems: (20882) 2000 VH57 & (6245) IKUFUMI & (250162) 2002 TY_57

Nov 20 On this day, 5 years ago: "Asteroids named after Thomas Pynchon & Stabia"  #astronomy #pynchon #stabia #asteroids

Dec 03 Dec 03 NASA’s Origins, Spectral Interpretation, Resource Identification, Security-Regolith Explorer (OSIRIS-REx) spacecraft completed its 2 billion-kilometer journey to arrive at the asteroid Bennu Monday. The spacecraft executed a maneuver that transitioned it from flying toward (101955) Bennu to operating around the asteroid. This series of images below, taken by the OSIRIS-REx spacecraft, shows Bennu in one full rotation from a distance of around 580 km. The spacecraft’s PolyCam camera obtained the 36 2.2-millisecond frames over a period of four hours and 18 minutes.

Credits: NASA/Goddard/University of Arizona

Dec 17 Comet 46P/Wirtanen imaged by E. Guido on 2018-12-17 at 11:45:26UT remotely from Bathurst Observatory Australia (MPC Q67). Single 20-second frame by 0.28-m f/2.2 reflector + CCD (ZWO 1600 Color) #astronomy #comets

Dec 18 Discovery by Sheppard, Tholen & Trujillo of new Solar System object 2018 VG18 ( nicknamed “Farout”) around 120 AU, making it the first Solar System object observed beyond 100 AU  &  #astronomy

Credits:  R. Molar Candanosa, S. Sheppard, Carnegie Institution for Science

Dec 20 Comet 46P/Wirtanen imaged on Dec. 13, 2018 by @NASAHubble space telescope  #astronomy #comets #Comet46pwirtanen #CometWirtanen

Credits: NASA, ESA, D. Bodewits and J.-Y. Li

Dec 21 Comet 46P/Wirtanen observed on Dec. 15, 2018 by astronomers at @AreciboRadar @NAICobservatory. The new radar observations provided the first definitive measurements of 46P/Wirtanen’s diameter, which is approximately 1.4 km (0.9 miles).  #astronomy #comets

Credits: Arecibo Observatory, NASA, NSF

Dec 26 Radar images of near-Earth asteroid 2003 SD220 obtained on Dec. 15-17 #astronomy #asteroids

Credits: NASA/Arecibo/USRA/UCF/GBO/NSF

by Ernesto Guido

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