Comets & Asteroids - Summary for Nov & Dec 2019

During the 2-month period November through December 2019, 4 new comets were discovered and there was 1 comet recovery. "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

- Cometary activity detected

- Comet Recoveries

- Other news

UNDER CONSTRUCTION

Comets & Asteroids - Summary for Sept & Oct 2019

During the 2-month period September through October 2019, 9 new comets were discovered, cometary activity was detected for 1 previously discovered object (earlier designated as asteroids) and there were 6 comet recoveries. "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

Sep 10 Discovery of C/2019 Q3 (PANSTARRS)            (CBET 4665)
Sep 12 Discovery of C/2019 Q4 (BORISOV)                 (CBET 4666)
Oct 05 Discovery of P/2019 S2 (PANSTARRS)             (CBET 4673)
Oct 05 Discovery of P/2019 S3 (PANSTARRS)             (CBET 4674)
Oct 16 Discovery of C/2019 T3 (ATLAS)                       (CBET 4678)
Oct 23 Discovery of C/2019 T4 (ATLAS)                       (CBET 4681)
Oct 23 Discovery of C/2019 T5 (ATLAS)                       (CBET 4682)
Oct 24 Discovery of P/2019 T6 (PANSTARRS)             (CBET 4684)
Oct 28 Discovery of P/2019 U4 (PANSTARRS)             (CBET 4688)

- Cometary activity detected

Oct 06 Cometary activity detected in 2018 DO4 =  C/2018 DO_4 (LEMMON)  (CBET 4675)

- Comet Recoveries

Sep 08 Recovery of P/2007 T4 (GIBBS) as P/2019 R2                   (CBET 4662)
Sep 09 Recovery of P/2008 Y1 (BOATTINI) as P/2019 R1            (CBET 4663)
Sep 27 Recovery of P/2006 R1 (SIDING SPRING) as P/2019 S1  (CBET 4671)
Oct 25 Recovery of P/2006 W1 (GIBBS) as P/2019 U1                 (CBET 4685)
Oct 28 Recovery of P/2006 F1 (KOWALSKI) as P/2019 U2          (CBET 4686)
Oct 28 Recovery of P/2004 WR_9 (LINEAR) as P/2019 U3          (CBET 4687)

- Other news

Sep 04 New paper on Arxiv by D. Jewitt & J. Luu: "Disintegrating In-Bound Long-Period Comet C/2019 J2".

Credit: Jewitt & Luu

Sep 16 Analysis of a bright flash in Jupiter’s atmosphere observed by an amateur astronomer in August 2019 has revealed that the likely cause was a small asteroid with a density typical of stony-iron meteors. The impact is estimated to have released energy equivalent to an explosion of 240 kilotons of TNT – around half the energy released in the 2013 Chelyabinsk event at Earth.

Credit: E. Chappel/R. Hueso

Oct 07 Saturn Surpasses Jupiter After The Discovery Of 20 New Moons. A team led by Carnegie's Scott S. Sheppard has found 20 new moons orbiting Saturn.  This brings the ringed planet’s total number of moons to 82, surpassing Jupiter, which has 79. 

Credit: NASA/JPL-Caltech/Space Science Institute/Sartorio/Shutterstock

Oct 08 The 2019 #NobelPrize in Physics has been awarded with one half to James Peebles “for theoretical discoveries in physical cosmology” and the other half jointly to Michel Mayor and Didier Queloz “for the discovery of an exoplanet orbiting a solar-type star”.

Credit: Mayor & Queloz

Oct 28 Beautiful images from VLT/SPHERE of the fourth biggest asteroid, Hygiea, found a big surprise: an almost spherical shape. It was hit in the past by a big impact which shattered and reassembled it while still fluid.

Credit: Vernazza et al.

by Ernesto Guido

V659 SCUTI = NOVA SCUTI 2019

Following the posting on the Central Bureau's Transient Object Confirmation Page about a possible Nova in Scutum (TOCP Designation: PNV J18395972-1025415) I performed some follow-up of this object through a TEL 0.6-m f/6.5 astrograph + CCD located in the El Sauce Observatory in Chile and operated by Telescope Live network.  

On images taken on October 31.01, 2019 I can confirm the presence of an optical counterpart with R-filtered CCD magnitude about +8.4 (saturated in a 10-second exposure) at coordinates:

R.A. = 18 39 59.71, Decl.= -10 25 41.9

(equinox 2000.0; Gaia DR2 catalogue reference stars for the astrometry).

This transient was discovered (discovered magnitude 11.5 g-Sloan Filter) by the All-Sky Automated Survey for Supernovae (ASAS-SN) on 2019 Oct. 29 at 01:12UT and reported to Transient Name Server (TNS) on Oct. 29 at 02:07:49 UTC as ASASSN-19aad = AT 2019tpb. According to CBET 4690, several independents discoveries have been reported to the Central Bureau of a nova in Scutum: Koichi Nishiyama (unfiltered magnitude 9.4 on Oct. 29.397), Hideo Nishimura (unfiltered magnitude 9.8 on Oct. 29.421), Shizuo Kaneko (unfiltered magnitude 9.8 on Oct. 29.462) (on AAVSO VSX is reported also Fujio Kabashima as independent discoverer). 

Spectroscopy by S. C. Williams et al. (see ATel #13241) & by  M. Pavana et al. (see ATel #13245) show that AT 2019tpb/ASASSN-19aad is a Galactic nova in the early stages of eruption.

N. Samus writes that the permanent GCVS designation V659 Sct has been assigned to this nova.

Below my confirmation image (sum of two unfiltered 30-sec exposure through a 0.6-m f/6.5 astrograph + CCD; El Sauce Observatory, Chile). Click on the image for a bigger version: 

An animation showing a comparison between my image and the archive POSS1 Blue plate (1951-07-30).

Below the same animation with a larger field of view. At the bottom left of V659 Sct you will notice a star occupying a different position in the new image with respect to the 1951 archive image. This star (Gaia designation DR2 4155146598548456064) is a high proper  motion star. Most stars are so distant that their apparent motion even over hundreds of years is all but negligible to naked eye observers. Some stars have very significant movements compared to the background stars (Click on it for a bigger version:

Below an image that is the difference between the new image and the archive image useful to highlight the "new" objects. There you can easily see the new galactic nova V659 Sct and the  high proper motion star.

by Ernesto Guido

Comet Images from the Dark Sky Of Chile

Below you can find a selection of some of the comets we imaged in the last few days using remotely a Planewave Telescope CDK24 a 0.61-m f/6.5 reflector + CCD located in the El Sauce Observatory in Chile. The telescope is owned by "TELESCOPE LIVE" network and we would like to thank them for allowing us to use their telescope for these images free of charge. Click on each image for a bigger version.

68P/Klemola  - 2019, September 27

29P/Schwassmann–Wachmann -  2019, September 27

101P/Chernykh - 2019, September 30

C/2017 U7 - 2019, September 30

C/2016 M1 (PANSTARRS) - 2019, October 06

by Ernesto Guido

Comets & Asteroids - Summary for July & August 2019

During the 2-month period July through August 2019, 7 new comets were discovered and there were 4 comet recoveries. "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/2019 L3 (ATLAS)                  (CBET 4644)
Jul 02 Discovery of C/2019 K7 (SMITH)                  (CBET 4645)
Jul 02 Discovery of C/2019 K8 (ATLAS)                  (CBET 4646)
Jul 03 Discovery of C/2019 LB_7 (KLEYNA)           (CBET 4647)*
Jul 15 Discovery of C/2019 N1 (ATLAS)                  (CBET 4650)
Jul 17 Discovery of P/2019 M2 (ATLAS)                  (CBET 4651)**
Jul 18 Discovery of C/2019 M3 (ATLAS)                  (CBET 4653)

*The available astrometry for this very faint object was published on MPEC 2019-N20, where it was inadvertently given the minor-planet designation 2019 LB_7 by the Minor Planet Center.

**Following a private remark by the D. Green that the orbital elements of comets D/1884 O1 (Barnard) and P/2019 M2 are similar, Nakano has attempted an investigation into the possibility that the two designations might refer to the same comet. Nakano remarks that he is unable to link the two orbits, suggesting that (while possibly related) the two comets seem to be different objects. Additional astrometry for P/2019 M2 is urgently needed to extend the arc of observations at this return, before the comet fades rapidly in the coming weeks.(CBET 4657)

- Comet Recoveries

Jul 06 Recovery of P/2006 S1 (CHRISTENSEN) as P/2019 M1     (CBET 4649)
Jul 17 Recovery of 39P/OTERMA                                                   (CBET 4652)*
Jul 28 Recovery of P/2014 U2 (KOWALSKI) as P/2019 O1          (CBET 4654)
Aug 09 Recovery of P/2010 U2 (HILL) as P/2019 P1                    (CBET 4658)

*Recovery of comet 39P/Oterma (magnitude 24) on CCD images taken on July 3 UT with the 8.1-m "Gemini South" telescope, with confirmatory follow-up images being obtained on July 5 using both the 8.1-m "Gemini South" and the 6.5-m Magellan-Clay telescopes.  A point-source object was located within 1" of an ephemeris generated by the orbit given on MPC 75716.An upper bound of the nucleus radius -- based on photometry of the July 3 and 5 individual 100-s r' images and assuming a 4-percent albedo -- is between 2.1 and 2.5 km.  This upper bound is lower than what would be derived from 2001 photometry reported on MPCs 43260 and 43446 (2.5-3.5 km), suggesting that there might have been a compact coma in those observations and/or that 39P has an elongated nucleus.The comet was last seen in 2001 (cf. IAUC 7689). Comet 39P is currently inbound with perihelion in 2023. The comet was missed at its 1983 return.

- Other news

Jul 08 Zwicky Transient Facility (ZTF) spotted an unusual asteroid with the shortest "year" known for any asteroid. The rocky body, dubbed 2019 LF6, is about a kilometer in size and circles the sun roughly every 151 days. In its orbit, the asteroid swings out beyond Venus and, at times, comes closer in than Mercury, which circles the sun every 88 days. 2019 LF6 is one of only 20 known "Atira" asteroids, whose orbits fall entirely within Earth's. In the images below you can see an animation showing the asteroid as captured by ZTF on June 10 and how the orbit of 2019 LF6 (white) falls entirely within the orbit of Earth (blue).

Credit: ZTF/Caltech Optical Observatories

Credit: NASA/JPL-Caltech

Jul 12 ATel #12931 Disintegration of Comet C/2019 J2 (Palomar) - Quanzhi Ye et al. report the apparent disintegration of comet C/2019 J2 (Palomar), first detected by Soulier and Sárneczky on images taken on UT 2019 July 6-7. After receiving the reports from Soulier and Sárneczky, Ye examined the images taken with the Zwicky Transient Facility (ZTF) operated on the 1.2-m Oschin Schmidt telescope at Palomar Observatory. The ZTF image on July 9 shows that the comet has lost its central condensation. Although the disintegration only becomes apparent at some time between the ZTF observation on July 2 and the Maisoncelles/Konkoly observation on July 6, ZTF photometry suggests that the process likely started much earlier, possibly in early May. The brightness of the comet increased by ~0.6 mag from Apr. 27 to May 9, then decreased by an equal amount from May 9 to Jul. 2, while a typical comet would have brightened by 1.0 mag from Apr. 27 to Jul. 2.

Jul 29 Austrian filmmaker Christian Stangl combined some of the more than 400,000 images taken by @ESA's Rosetta mission into a stunning short film: "the Comet". Together the images show details of Comet 67P, which Rosetta followed and researched for 2 years.

Aug 07 On July 24, asteroid 2019 OK (60-130 meters in size; discovered by SONEAR team @CrisJacques)  approached Earth at about 65,000 km above the surface, one fifth the distance to the Moon. Largest Asteroid To Pass This Close To Earth in a Century

Credits: P. Chodas (NASA/JPL)

Aug 08 A possible impact on Jupiter recorded on 07 August 2019 at 04:07 UTC by E. Chappel. This is not the first time that we have seen something slam into Jupiter. It's actually the seventh event of its kind in recent years. More info about past recent events are available here

Credits: E. Chappel

Credits: E. Chappel

Aug 17 Fireball over Sardinia, Italy on the evening of August 16, 2019 via @ClaudioPorcu - More video available here  #meteor #meteora #astronomy #astronomia #Sardegna

Credits: C. Porcu

Below you can see a map showing the trajectory in the atmosphere projected to the ground of this bolide. The triangulation was done using 6 visual observations selected among the more than 80 arrived at the IMO.

(Credits: A. Carbognani)

by Ernesto Guido

Comets & Asteroids - Summary for May & June 2019

During the 2-month period May through June 2019, 11 new comets were discovered and there were 2 comet recoveries. "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

May 04 Discovery of C/2019 H1 (NEOWISE)                  (CBET 4623)

May 12 Discovery of C/2019 J1 (LEMMON)                   (CBET 4625)

May 13 Discovery of C/2019 J2 (PALOMAR)                  (CBET 4626)

May 23 Discovery of C/2019 K1 (ATLAS)                    (CBET 4629)

May 23 Discovery of C/2019 J3 (ATLAS)                    (CBET 4630)

May 24 Discovery of C/2019 JU_6 (ATLAS)                  (CBET 4631)*

Jun 24 Discovery of C/2019 K4 (YE)                       (CBET 4636)

Jun 28 Discovery of C/2019 K5 (YOUNG)                    (CBET 4637)

Jun 28 Discovery of C/2019 L1 (PANSTARRS)                (CBET 4640)

Jun 28 Discovery of C/2019 L2 (NEOWISE)                  (CBET 4641)

Jun 30 Discovery of C/2019 K1 (ATLAS)                    (CBET 4643)

* Apparently asteroidal object that was discovered on CCD images obtained on 2019 May 12.5 with a 0.5-m reflector at Haleakala in the course of the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) search program), and given the minor-planet designation 2019 JU_6 by the Minor Planet Center (cf. MPS 996641; orbit on MPEC 2019-J141 from a two-day arc), has been found to show cometary appearance by CCD astrometrists elsewhere.

- Comet Recoveries

Jun 03 Recovery of P/2000 S4 (LINEAR-SPACEWATCH) as P/2019 K2     (CBET 4633)

Jun 04 Recovery of P/2007 R1 (LARSON)            as P/2019 K3     (CBET 4635)

- Other news

May 01 Miklós Lovas, most successful Hungarian discoverer, has passed away at the age of 88 years on April 18th. He discovered 42 supernovae, 5 comets (including 93P & 184P) and 2 unusual minor planets at the Konkoly Obs. between 1964 and 1995 via K. Sárneczky

May 10 (CBET 4624) OUTBURST OF 15-BOOTIDS METEOR SHOWER - P. Jenniskens, SETI Institute and NASA Ames Research Center, and E. Lyytinen, Finland, report activity of the 15-Bootid meteors (IAU shower 923, code FBO) between 2019 Apr. 21d22h01m and 22d00h13m UTC, corresponding to solar longitude 31.24-31.34 degrees (equinox J2000.0). Six 15-Bootids were detected between 22h01m and 00h12m UTC by the low-light video cameras of the CAMS BeNeLux network (coordinated by C. Johannink) during routine observations that were made during 19h50m-03h15m UTC that night. The orbital elements bear some resemblance to those of the bright comet C/539 W1 (parabolic orbital elements q = 0.16 +/- 0.15 AU, i = 19 +/- 6 deg, Argument of Perihelion = 246 +/- 40 deg, Node = 33 +/- 20 deg; cf. Hasegawa 1979, PASJ 31, 257).  The broad 2-hr duration of the shower, presumably requiring somewhat higher ejection velocities, is consistent with a relatively large comet.

May 17 (CBET 4627) NEW SATELLITE AROUND (31) EUPHROSYNE - P. Vernazza, B. Carry, F. Vachier, J. Hanus, J. Berthier, B. Yang, F. Marchis and the HARISSA team report the discovery of a satellite around minor planet (31) Euphrosyne.  They observed (31) Euphrosyne with the Very Large Telescope (+ SPHERE/ZIMPOL) at six different epochs between 2019 Mar. 15 and Apr. 10.  On Mar. 15.301 UT, the satellite was at a separation of 0".398 arcsec (projected separation 651 km) in p.a. 268.49 degrees; on Apr. 10.109, the satellite was found at a separation of 0".384 in p.a. 87.0 degrees. Based on these detections, the mean magnitude difference through an N_R filter (central wavelength 645.9 nm; bandwidth 56.7 nm) between (31) and its companion is 8.0 +/- 0.8, implying a diameter of about 6 km.  Preliminary orbit computation indicates an orbital period of about 1.2 days for the satellite, with a semi-major axis of 677 km.

May 17 CBET 4628, CBET 4632 (May 29), CBET 4634 (Jun 03) report that the following minor planets are binaries systems: (2873) BINZEL, (72036) 2000 XM44 & (1344) CAUBETA

May 23 "From Centaurs to comets - 40 years" - Review chapter to be published in the book "The Transneptunian Solar System" #astronomy #comets #centaurs

Credit: Peixinho et al.

Jun 04 The #VLT instrument #SPHERE observed the double asteroid (66391) 1999 KW4 as it flew by Earth on 25 May #astronomy #asteroids

Credit: ESO

Jun 06 HiPOD: A new impact crater on Mars, formed between Sept 2016 and Feb 2019. What makes this stand out is the darker material exposed beneath the reddish dust.

: NASA/JPL/University of Arizona

Jun 19 ‘Comet Interceptor’ has been selected as ESA’s new fast-class mission in its Cosmic Vision Programme. Comprising three spacecraft, it will be the first to visit a truly pristine comet or other interstellar object that is only just starting its journey into the inner Solar System.

Jun 28 (CBET 4638) 2019 MO - An 18th-magnitude fast-moving asteroidal object, detected on June 22.3 and 22.4 UT with the Pan-STARRS2 1.8-m Ritchey-Chretien reflector at Haleakala and the ATLAS 0.5-m reflector at Mauna Loa and designated 2019 MO by the Minor Planet Center on MPEC 2019-M72 (which contains astrometry and orbital elements), impacted the earth's atmosphere around June 22.896 UT.  It was evidently detected in daylight satellite imagery over the Caribbean Sea. The absolute magnitude of 29.3 suggests a size prior to entry on the order of 3-4 meters. This is fourth known object to hit the earth's atmosphere after detection in space prior to impact (cf. CBET 4519).

Jun 29 (CBET 4642) JUNE EPSILON OPHIUCHID METEORS - P. Jenniskens, SETI Institute and NASA Ames Research Center, reports unusual activity of the June epsilon Ophiuchids shower (IAU shower 459, code JEO) between 2019 June 19d08h and 26d05h UTC, corresponding to the solar longitude range 87.5-94.1 degrees, with most activity between solar longitude 89.3 and 93.3 degrees, centered on 92.11 degrees (equinox J2000.0).  Eighty-eight June epsilon Ophiuchids were detected by CAMS camera network on June 19-26. The orbital elements resemble those of the Jupiter-family comet 300P/Catalina (q = 0.826 AU, a = 2.695 AU, i = 5.69 degrees, Peri. = 222.75 degrees, Node = 95.81 degrees, and longitude of perihelion 318.56 degrees. The outburst confirms the existence of this otherwise minor shower (cf. Rudawska and Jenniskens 2014, Meteoroids 2013, p. 217) and offers evidence of past activity of its parent body.

Bright June epsilon Ophiuchid shower meteor captured on 2019, June 24

Credit: Rancho Mirage Observatory (Eric McLaughlin)

by Ernesto Guido

Small Asteroid 2019 MO (NEOCP A10eoM1) impacted Earth on June 22

On 2019 June 22.40, the Atlas Project Survey (T08 Mpc code) found a small asteroid that was soon after put on the NEOCP list with the provisional designation A10eoM1 for the follow-up by other observers. The Minor Planet Center subsequently assigned the following official designation to this object 2019 MO (see update below).

Davide Farnocchia at JPL noticed "that the T08 NEOCP observations could generate an impact prediction matching the observed point and time on the earth of a fireball recorded on June 22 at about 21:30UT.  That led to an orbit - this is where A10eoM1 would have been,  based on the four ATLAS observations and assuming it really was this particular impactor - good enough to do precovery searches through the PanSTARRS data (F52 Mpc code)." (via Bill Gray, private communication).

In fact using all the available observations of 2019 MO NEOCP A10eoM1  by F52 & T08, FINDORB software finds an IMPACT on June 22, 2019 at 21:31:54UT at Lat +15.02 & Long W68.65 that seems remarkably close to data of a fireball off the South coast of Jamaica as shared on Twitter by Peter Brown & Frankie Lucena

Credit: FINDORB - B. Gray

Below you can see the event as captured by the GLM  (via F. Lucena)

Credit: SLIDER by RAMMB / CIRA @ CSU

According to P. Brown: Airwaves recorded by Bermuda infrasound station 2000 km North show periods which are consistent with 5 kT bolide corresponding to a 3m diameter object NEA impact.

This is only the fourth time in history that an impacting object is observed prior to atmospheric entry. The first time it happened was with asteroid 2008 TC3, the second was with asteroid 2014 AA, the third was 2018 LA that impacted Earth on 02 June 2018. Another space impacting object discovered prior to its to atmospheric entry was WT1190F but it is thought to have been a space debris, possibly  the translunar injection module of Lunar Prospector. For more info about 2008 TC3, 2014 AA and 2018 LA see also:

http://remanzacco.blogspot.it/2008/10/small-asteroid-2008-tc3-to-hit-earth.html

http://remanzacco.blogspot.com/2008/10/2008-tc3-animation.html

http://remanzacco.blogspot.com/2008/10/2008-tc3-update-impact-flash-imaged.html

http://remanzacco.blogspot.com/2008/11/2008-tc3-trail-imaged-over-northern.html

http://remanzacco.blogspot.it/2009/02/2008-tc3-fragments-recovered.html

http://remanzacco.blogspot.com/2014/01/small-asteroid-2014-aa-hit-earths_2.html

https://remanzacco.blogspot.com/2018/06/small-asteroid-2018-la-impacted-earth.html 

http://remanzacco.blogspot.com/search/label/asteroid%20impact

UPDATE - June 25, 2019 @15:40UT

M.P.E.C. 2019-M72  issued on 2019 June 25 at 14:59 UT assign the official designation 2019 MO to A10eoM1 with the following comment:

The orbit below indicates an impact with the earth's atmosphere around June 22 21:30 UTC.  This is in good agreement with the details determined by D. Farnocchia with the JPL Scout System (June 22 21:32 UTC +/- 15 minutes) and W. Gray (June 22 21:30:33 UTC +/- "a few minutes").                               

UPDATE - June 26, 2019 @06:40UT

The UHIfA (Institute for Astronomy - Univeristy of Hawaii) press release about 2019 MO is online on their website describing their effort to locate Pan-STARRS 2 (PS2) precovery images of the asteroid following Farnocchia's advice: "Luckily, the Pan-STARRS 2 (PS2) telescope on Haleakalā was operating at the same time, and two hours prior to the ATLAS observations had imaged the part of the sky where 2019 MO should have been seen. The asteroid was located on a part of the PS2 camera that is not fully operational, but PS2 scientists Robert Weryk and Mark Huber, at the University of Hawai'i Institute for Astronomy (IfA) and Marco Micheli at the European Space Agency (ESA), were able to analyze these PS2 images and find the asteroid."

A map of the predicted trajectory and final impact location for asteroid 2019 MO

Credit: Larry Denneau (IfA/ATLAS), Brooks Bays (SOEST)

UPDATE - July 31, 2019

This impact event has been added to CNEOS "Fireball and Bolide Data" webpage with a calculated total impact Energy of 6 kt (impact energy of the event in kilotons of TNT) on 2019-06-22 at 21:25:48 (event's peak brightness). According to P. Brown: "Energy of 6 kT compares well with earlier infrasound estimate. NEA was 5m in diameter with a mass of about 200 T. This is statistically the largest annual impactor at Earth". 

The trail at the centre of the image below is the earliest known detection of 2019 MO. The image was obtained by Pan-STARRS2 telescope at 07:54 UT of the impact day, 13.5 hours before the object entered into Earth's atmosphere. (via ESA's SSA-NEO Coordination Centre).

Credits: R. Weryk, M. Huber, R. J. Wainscoat (Pan-STARRS(IfA/UH/NASA)

by Ernesto Guido

New Comet C/2019 J1 (Lemmon)

CBET 4625 & MPEC 2019-J122, issued on 2019, May 12,  announce the discovery of a comet (magnitude ~17.5) in the course of the "Mt. Lemmon Survey" (G96), in images taken on 2019, May 04 with a 1.5-m reflector + 10K CCD. This object was reported as a comet by R. A. Kowalski and D. Rankin (G96, May 4). The new comet has been designated C/2019 J1 (Lemmon).  

I performed follow-up measurements of this object while it was still on the PCCP webpage. Stacking of 12 unfiltered exposures, 120 seconds each, obtained remotely on 2019, May 06.4 from H06 (iTelescope network) through a 0.25-m f/3.4 reflector + CCD, shows that this object is a comet with a diffuse coma about 10 arcsec in diameter.

My confirmation image (click on it for a bigger version)

Credit: Minor Planet Center 

M.P.E.C. 2019-J122, assigns the following preliminary orbital elements to comet  C/2019 J1: T 2019 Apr. 8.80; e= 0.97; Peri. =  167.59; q = 2.48;  Incl.= 24.54


Below you can see an image of comet C/2019 J1 (C0M96K2 was its PCCP provisional designation) taken on 2019, May 05, by its discoverers.

Credit: Catalina Sky Survey - Courtesy Kowalski & Rankin

by Ernesto Guido

Comets & Asteroids - Summary for March & April 2019

During the 2-month period March through April 2019, 6 new comets were discovered and there were 3 comet recoveries. "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

Mar 21 Discovery of C/2019 D1 (FLEWELLING)                  (CBET 4614)

Mar 21 Discovery of C/2019 E3 (ATLAS)                                (CBET 4615)

Apr 10 Discovery of P/2019 G1 = P/2011 O2 (PANSTARRS) (CBET 4618)* 

Apr 10 Discovery of C/2019 F1 (ATLAS-AFRICANO)           (CBET 4619) 

Apr 22 Discovery of C/2019 F2 (ATLAS)                                (CBET 4620) 

Apr 23 Discovery of P/2019 GG_21 (PANSTARRS)               (CBET 4621)** 

* G. V. Williams, Minor Planet Center, then identified additional pre-discovery (apparently stellar) observations obtained at Kitt Peak by T. H. Bressi with the 1.8-m Spacewatch II on 2009 Feb. 26 and at the XuYi Station of  Purple Mountain Observatory with a 1.04-m Schmidt telescope on 2009 Mar. 25.

**  Initially designated as minor planet 2019 GG21, there was one prior report of cometary activity in this object. R. Weryk and R. Wainscoat (F51, Apr. 4) reported a ~1".9 FWHM ("seemingly" larger than the 1".4 +/- 0".2 FWHM of nearby stars) and a slight asymmetry to the northwest.  No other credible cometary reports were received.  A  report received today of a "new comet" (remarking that 2019 GG21 was predicted to be "nearby") from S. Sheppard  (807,Apr. 4 and 5) noted that the object had a 21" tail in P.A. 310.  The object is therefore being redesignated P/2019 GG21.

- Comet Recoveries

Mar 10 Recovery of P/2003 L1 (SCOTTI) as P/2019 E1     (CBET 4612)

Mar 18 Recovery of P/2005 Y2 (McNAUGHT) as P/2019 E2   (CBET 4613)

Apr 03 Recovery of P/2006 F4 (SPACEWATCH) as P/2019 D2 (CBET 4616)

- Other news

Mar 06 Image sequence captured by CAM-H during the touchdown of @haya2e_jaxa @haya2_jaxa spacecraft with  asteroid (162173) Ryugu last month. Also on youtube http://bit.ly/2VFTpfy  #astronomy #asteroids #ryugu

Credits: JAXA

Mar 12 New paper on Arxiv by D. Seligman, G. Laughlin & K. Batygin: "Implications of the Small Spin Changes Measured for Large Jupiter-Family Comet Nuclei". Long-form blog post up on http://oklo.org/2019/03/12/on-oumuamua/

Mar 19 OSIRIS-REx caught asteroid Bennu ejecting particles from its surface. NavCam 1 imager captured the first-ever close-up observations of material being released from an “active asteroid.” 

Credits: NASA/Goddard/University of Arizona/Lockheed Martin

Mar 27 The gigantic 170 ft (52 m) boulder on asteroid Bennu #Bennu #OSIRISREx #Asteroid via Roman Tkachenko

Credits: NASA/Goddard/University of Arizona/Lockheed Martin

Mar 28 Active asteroid (6478) Gault imaged by Hubble Space Telescope. Images from Hubble show two narrow, comet-like tails of dusty debris streaming from the asteroid (6478) Gault. Each tail represents an episode in which the asteroid gently shed its material.

Credits: NASA, ESA, Meech & Kleyna (University of Hawaii) and Hainaut (ESO)

Apr 05 The Hayabusa2 deployable camera, DCAM3, successfully photographed the ejector from when the SCI  (Small Carry-on Impactor） collided with Ryugu’s surface: "This is the world’s first collision experiment with an asteroid! In the future, we will examine the crater formed and how the ejector dispersed".  (see image below. Image credits: JAXA, Kobe University, Chiba Institute of Technology, The University of Occupational and Environmental Health, Kochi University, Aichi Toho University, The University of Aizu, and Tokyo University of Science)

UPDATE Apr 25 Crater formation where the Small Carry-on Impactor collided with Ryugu has been confirmed! These images compare the surface before and after the SCI collision.

Credit: Hayabusa2 JAXA

Apr 05 (CBET 4617) P. Jenniskens, SETI Institute and NASA Ames Research Center; and J. W. Baggaley, University of Canterbury, Christchurch, report that an outburst of delta Pavonid meteors (IAU shower 120; code DPA) has been detected by the CAMS New Zealand stations operated by P. Aldous (Geraldine) and I. Crumpton (West Melton).The parent comet is presumed to be C/1907 G1 (Grigg-Mellish), which was poorly observed in 1907, with parabolic orbital elements q = 0.924 AU, i = 110.06 deg, Peri. = 328.76 deg, and Node = 190.417 deg (equinox 2000.0) -- in good agreement when allowing for the motion of the node due to planetary perturbations.

Credits: NASA Meteor Shower Portal; CAMS SETI

Apr 15 New paper on Arxiv by D. Jewitt et al.: "Episodically Active Asteroid 6478 Gault".

Credit: Jewitt et al.

Apr 23 New paper on Arxiv by Chandler et al.: "Six Years of Sustained Activity from Active Asteroid (6478) Gault".

Credits: Chandler et al.

Apr 24 Three months of surface temperature maps of #67P nucleus from Rosetta suggest that only the upper layers are affected by temporal effects, keeping the immediate interior pristine.

Credits: F. Tosi et al - Nature Astronomy 2019

by Ernesto Guido

Comets & Asteroids - Summary for Jan & Feb 2019

During the 2-month period January through February 2019, 14 new comets were discovered. Moreover inner main-belt minor planet (6478) GAULT developed a lengthening tail or trail. "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

Jan 02 Discovery of P/2018 Y2 (AFRICANO)      (CBET 4590)
Jan 07 Discovery of P/2019 A1 (PANSTARRS)   (CBET 4591)
Jan 08 Discovery of P/2019 A2 (ATLAS)            (CBET 4595)
Jan 10 Discovery of P/2019 A3 (PANSTARRS)   (CBET 4598)
Jan 17 Discovery of P/2019 A4 (PANSTARRS)   (CBET 4600)
Jan 17 Discovery of C/2019 A5 (PANSTARRS)   (CBET 4601)
Jan 17 Discovery of P/2019 A6 (LEMMON-PANSTARRS)   (CBET 4602)
Jan 23 Discovery of C/2019 B1 (AFRICANO)    (CBET 4604)
Jan 23 Discovery of P/2019 A7 (PANSTARRS)   (CBET 4605)
Feb 04 Discovery of P/2018 V5 (TRUJILLO-SHEPPARD)   (CBET 4607)*
Feb 04 Discovery of P/2019 A8 (PANSTARRS)   (CBET 4608)
Feb 04 Discovery of P/2019 B2 (GROELLER)    (CBET 4609)
Feb 07 Discovery of C/2019 A9 (PANSTARRS)   (CBET 4610)
Feb 27 Discovery of C/2019 B3 (PANSTARRS)   (CBET 4611)

* S. Sheppard reported that this object showed a ~9" tail in P.A. 276 on 2018 Nov. 7 and a 19" tail in P.A. 277 on 2019 Jan. 8.  The comet was detected by C. Trujillo on images taken by Sheppard.  R. Weryk reported prediscovery images that showed the object with a  1".3 FWHM (compared to 1".10 +/- 0".05 for nearby stars) on 2017 Oct. 28.

- Other news

Jan 07 CBET 4592, CBET 4593 (Jan 08), CBET 4596 (Jan 09), CBET 4599 (Jan 16) report that the following minor planets are binaries systems: (2337) BOUBIN, 2016 AZ_8, (7393) LUGINBUHL & (2070) HUMASON

 

Jan 08 CBET 4594 (issued on 2019, January 08) announces the serendipitous discovery by the "Asteroid Terrestrial-Impact Last Alert System" (ATLAS) team of unusual activity associated with the inner main-belt minor planet (6478) which appears to have developed a lengthening tail or trail. 

by Ernesto Guido