Thursday, August 30, 2018

Comets & Asteroids - Summary for June & July 2018

During the 2-month period June through July 2018, 7 new comets were discovered, cometary activity was detected for 1 previously discovered object (earlier designated as asteroids) 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

Jun 09 Discovery of P/2018 L1 (PANSTARRS) (CBET 4521)
Jun 09 Discovery of C/2018 L2 (ATLAS)          (CBET 4522)
Jun 22 Discovery of P/2018 L4 (PANSTARRS) (CBET 4527)
Jul 02 Discovery of P/2018 L5 (LEONARD)     (CBET 4528)
Jul 02 Discovery of C/2018 M1 (CATALINA)   (CBET 4529)
Jul 07 Discovery of C/2018 N1 (NEOWISE)     (CBET 4532)
Jul 16 Discovery of C/2018 N2 (ASASSN)        (CBET 4534)

- Cometary activity detected

Jun 11 Cometary activity detected in 2018 EN4 = C/2018 EN4 (NEOWISE)

- Comet Recoveries

Jun 14  Recovery of P/2005 R1 (NEAT) as P/2018 L3 (CBET 4526)

- Other news

Jun 01 A New Impact Crater – Mars Reconnaissance Orbiter (MRO) keeps finding new impact sites on Mars. This one occurred within the dense secondary crater field of Corinto Crater.

Credit: NASA/JPL/University of Arizona

Jun 02 Small Asteroid 2018 LA (aka ZLAF9B2) IMPACTED Earth on 02 June 2018 

Credit: (CREDIT: Mt. Lemmon Survey - CSS).

Credit: Kokotanekova et al

Jun 09 CBET 4523 & CBET 4536 (Jul 20) report that the following minor planets are binaries systems: (15745) YULIYA & (4666) DIETZ

Jun 12 New paper on Arxiv by Masiero et al.: "Small and Nearby NEOs Observed by NEOWISE During the First Three Years of Survey: Physical Properties".

Jun 14 JAXA Hayabusa2 spacecraft starts sending images of asteroid (162173) Ryugu. Below you can see some images taken from a distance of 700km on June 14, 2018 and from a distance of about 6km on July 20, 2018.

Credit: JAXA

Credit: Jaxa

Jun 26 An asteroid impact triggered an avalanche on Mars as imaged by HiRISE camera on the Mars Reconnaissance Orbiter.

Credit: NASA/JPL/University of Arizona

Jun 27 New results indicate interstellar nomad `Oumuamua is a comet. The first interstellar object discovered in the Solar System, is moving away from the Sun faster than expected.

Credit: Micheli et al.

Jul 13 Radar images of the binary asteroid 2017 YE5 via @AreciboRadar & Green Bank Observatory on June 25 show it consists of two separate objects in orbit around each other that are roughly the same size.

Credit: Arecibo/GBO/NSF/NASA/JPL-Caltech

Jul 17 Jupiter has 10 more moons we didn't know about — and they're weird. The planet now has 79 known moons, including a tiny oddball on a collision course with its neighbours.

Jul 20 Comet C/2017 S3 (PANSTARRS) imaged by Michael Jaeger on July 20, 2018 @ Jauerling, Austria.

Credit: M. Jaeger

by Ernesto Guido

Monday, July 16, 2018

New Comet: C/2018 N2 (ASASSN)

MPEC 2018-O01, issued on 2018, July 16,  announces the discovery of a comet (magnitude ~16.1) in the course of the "All-Sky Automated Survey for Supernovae" (ASASSN) program, in images taken 2018 July 7-11 with the 14-cm "Cassius" survey telescope at Cerro Tololo. The new comet has been designated C/2018 N2 (ASASSN)

I performed follow-up measurements of this object, while it was still on the PCCP webpage. Stacking of 10 unfiltered exposures, 60 seconds each, obtained remotely on 2018, July 15.7 from Q62 (iTelescope network) through a 0.43-m f/6.8 astrograph + CCD, shows that this object is a comet with a diffuse coma about 15 arcsec in diameter.

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

For a different elaboration of this image please click here.

M.P.E.C. 2018-O01 assigns the following preliminary parabolic orbital elements to comet C/2018 N2: T 2019 Oct. 4.09; e= 1.0; Peri. =  23.85; q = 3.00;  Incl.= 78.31

This is the second comet discovered by ASASSN Survey (more info about their first comet are here).

by Ernesto Guido

Sunday, June 3, 2018

Small Asteroid 2018 LA impacted Earth on 02 June

M.P.E.C. 2018-L04 issued on 2018 June 3 at 16:15 UT reports the discovery of the asteroid 2018 LA (discovery magnitude 18.2) by Mt. Lemmon Survey (MPC code G96 - Observer R. A. Kowalski) on images taken on June 02.3 with a 1.5-m reflector + 10K CCD. 2018 LA is a small Apollo asteroid with an estimated size of 1.7 m - 5.2 m (based on the object's absolute magnitude H=30.6).

As reported on this MPEC:  

"This object no longer exists (in its original form), following its entry into the Earth's atmosphere on 2018 June 2.  A news item on the event is in preparation by JPL's Center for Near-Earth Object Studies.  The orbit below, based on only the given astrometric observations, indicates that the object reached 50-km height above the Earth's surface around 16:51 UTC over southern Africa". 

Below you can see the discovery images of 2018 LA (also known by it provisional NEOCP designation ZLAF9B2). The asteroid is the streak just at center of the image, surrounded by the purple circle.

(CREDIT: Mt. Lemmon Survey - CSS).

Below you can see the a map of the possible impact region made by Bill Gray (click on the image for a bigger version). The corresponding impact times and locations are listed here.

Credit: Bill Gray

The yellow circle and X in Botswana mark the lat/lon from the AMS reports (see below).  According to Bill: "The object came in at about altitude 16 degrees above the horizon, at azimuth 98 degrees (a little south of due east). The magenta dots on the plot are again for impact on an airless planet; the actual impact ought to be quite a bit to the east. Which matches the impact reports nicely" and "The magenta impact points run from the Atlantic most of the way through northern Namibia, which is just south of Angola. Shifted eastward after allowing for the fact that the object was presumably seen in the upper atmosphere, they'd move into Botswana."

To date American Meteor Society (AMS) received 8 reports possibly related to entry into the Earth's atmosphere of 2018 LA about a fireball seen over South-East District, Gauteng, North West and Northern Cape on Saturday, June 2nd 2018 around 16:45 UT. In particular one of the reports by Barend Swanepoel contains a video showing the fireball as seen from between Ottosdal and Hartebeesfontein North West South Africa. (another video related to this event and submitted to AMS is visible here ; see also this CCTV camera record from Kuruma Radiators, note that in this video camera time is about 26 minutes behind).

According to Peter Brown: "Strong infrasound detection of a bolide at station I47 in South Africa today at 1730 UT. Origin time between 1645-17 UT over Botswana. Yield 0.3-0.5 kT, corresponding to 2m diameter asteroid".

Credit: P. Brown

This is only the third 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. Curiously all these 3 events have been discovered by Richard A. Kowalski & Catalina Sky Survey (Richard is also the founder of MPML Minor Planet Mailing List celebrating this year its 20th anniversary). 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 and 2014 AA see also:

UPDATE - July 06, 2018

On Saturday, June 23, 2018, after five days of walking and scouring around a team of experts from Botswana, South Africa, Finland and the United States of America recovered a fresh-looking 18-g meteorite in Botswana's Central Kalahari Game Reserve (CKGR). The meteorite is one of the fragments of asteroid 2018 LA which collided with Earth on June 2, 2018 and turned into a meteor fireball that detonated over Botswana a few seconds after entering the atmosphere.

Credit: Peter Jenniskens

This is the third time in history that an asteroid inbound to hit Earth was detected early and only the second time that fragments were recovered. After disruption, the asteroid fragments were blown by the wind while falling down, scattering over a wide area. Calculations of the landing area were done independently by a US-based group headed by Peter Jenniskens, a subject expert of the NASA-sponsored SETI Institute in California, as well as Esko Lyytinen and Jarmo Moilanen of the Finnish Fireball Network (FFN).

Credit: Peter Jenniskens

by Ernesto Guido

Thursday, May 31, 2018

Comets & Asteroids - Summary for April & May 2018

During the 2-month period April through May 2018, 2 new comets were discovered, cometary activity was detected for 2 previously discovered objects (earlier designated as asteroids) 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

Apr 26  Discovery of P/2018 H2 (PANSTARRS)
May 31 Discovery of C/2018 K1 (Weiland)

- Cometary activity detected

Apr 17 Cometary activity detected in A/2018 F4 = C/2018 F4 (PANSTARRS) *
Apr 20 Cometary activity detected in 2018 EF9 = C/2018 EF9 (Lemmon)

* This object initially received the unusual designation A/2018 F4 by G. V. Williams on MPEC 2018-F139 because of the hyperbolic orbit.

See also MPEC 2018-H21: "This object, originally announced as A/2018 F4, is being redesignated as a comet.  K. Sarneczky, Konkoly Observatory, reports that five stacked 120-s unfiltered CCD images taken on Apr. 9.9 UT with the 0.60-m Schmidt telescope at Piszkesteto, Hungary, show a broad fan-shaped coma of diameter nearly 6", elongated toward the east.  R. Weryk (University of Hawaii) reports that images taken with the 3.6-m CFHT on Mauna Kea on Apr. 13.39 UT show that the object has a FWHM of 2".4 (larger than the 1".4 FWHM for nearby stars) and a broad, short tail towards the east".

- Comet Recoveries

Apr 18  Recovery of P/2011 CR42 (CATALINA) as P/2018 H1

- Other news

Apr 16 New paper on Arxiv by Jewitt et al.: "The Nucleus of Active Asteroid 311P/(2013 P5) PANSTARRS".

Credits: Jewitt et al.

Apr 23 New paper on Arxiv by Nesvorny et al.: "Bi-lobed Shape of Comet 67P from a Collapsed Binary".

Apr 24 Dust, stars, and cosmic rays swirling around Comet 67P, captured by the @ESA_Rosetta probe (processing by @landru79)

Credit: Esa Rosetta

Apr 25 Gaia Data Release 2: Observations of solar system objects. The Gaia spacecraft of the European Space Agency (ESA) has been securing observations of solar system objects (SSOs) since the beginning of its operations. Gaia Data Release 2 (DR2) contains the observations of a selected sample of 14,099 SSOs.  The published Gaia data set in data release 2 only contains a selected sample of asteroids, as the observations of many more have already been collected, and will become available in future releases. By the end of the mission there will most probably be more than 300.000, and the accurate positions, 100s times better than in the past, will disclosing new possibility of investigation. The pictures below show a colorful plot of the orbits of the asteroids in Gaia’s second data release (coloured according to perihelion distance), between the Sun and Jupiter. As usual in scaled plots, the Solar System appears crowded and individual lines merge in the region of the Main Belt, between Mars and Jupiter, where most asteroids concentrate. In reality, of course, these asteroid trajectories are millions of km apart.

Credit: Credit: ESA/Gaia/DPAC, P. Tanga

May 07 Silicon Valley Astronomy Lecture: Rubble Piles in the Sky | @michael_w_busch reviews the near-Earth population, programs to track and characterize near-Earth asteroids, and current efforts to address the danger of asteroid impacts. Watch it here on Youtube

May 09 ESO Press Release: Exiled Asteroid Discovered in Outer Reaches of Solar System - ESO telescopes find first confirmed carbon-rich asteroid in Kuiper Belt: "An international team of astronomers has used ESO telescopes to investigate a relic of the primordial Solar System. The team found that the unusual Kuiper Belt Object 2004 EW95 is a carbon-rich asteroid, the first of its kind to be confirmed in the cold outer reaches of the Solar System. This curious object likely formed in the asteroid belt between Mars and Jupiter and has been flung billions of kilometres from its origin to its current home in the Kuiper Belt."

May 11 OSSOS Survey, the complete data release is now published!  Eight hundred and forty precisely defined orbits, with a survey simulator calibrating their detection efficiency. Article by Michele Bannister for @ConversationUK: "How @OSSOSurvey discovered 840 minor planets beyond Neptune – and what they can tell us"

Credit: OSSOS Survey

May 15 New paper on Arxiv by Fernández et al.: "Dynamical evolution and end states of active and inactive Centaurs". 

Credit: Fernández et al.

May 21 New paper on Nature Astronomy by Shi et al..: "Coma morphology of comet 67P controlled by insolation over irregular nucleus". Shi et al. study the activity of comet #67P using #Rosetta images, finding that diffuse activity is controlled by sunlight and it can be focused by the roughness of the nucleus' surface to create the nice coma shapes.

Credit: ESA/Rosetta/MPS for OSIRIS Team MPS/UPD/LAM/IAA/SSO/INTA/UPM/DASP/IDA; Nature Astronomy

Credit: Hsieh et al.

May 28 New paper on Arxiv by J. Agarwal & M. Mommert: "Nucleus of active asteroid 358P/Pan-STARRS (P/2012 T1)". 

by Ernesto Guido

Friday, April 27, 2018

Comets & Asteroids - Summary Jan through Mar 2018

During the 3-month period January through March 2018, 12 new comets were discovered, cometary activity was detected for 3 previously discovered object (earlier designated as an asteroid) 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

Jan 11 Discovery of P/2017 Y3 (LEONARD)
Jan 11 Discovery of C/2018 A1 (PANSTARRS)
Jan 17 Discovery of C/2018 A3 (ATLAS)
Jan 17 Discovery of P/2018 A4 (PANSTARRS)
Jan 17 Discovery of P/2018 A5 (PANSTARRS)
Jan 24 Discovery of C/2018 A6 (GIBBS)

Feb 07 Discovery of C/2018 B1 (LEMMON)
Feb 11 Discovery of P/2018 C1 (LEMMON-READ)

Mar 16 Discovery of C/2018 E1 (ATLAS)
Mar 16 Discovery of C/2018 E2 (BARROS)
Mar 19 Discovery of C/2018 F1 (GRAUER)
Mar 28 Discovery of C/2018 F3 (JOHNSON)

- Cometary activity detected

Jan 08 Cometary activity detected in 2017 AB_5 = C/2017 AB_5 (PANSTARRS)
Feb 27 Cometary activity detected in 2011 WG_113 = P/2017 U6
Mar 28 Cometary activity detected in A/2018 C2 = C/2018 C2 (Lemmon) *

* The prefix for  this object is being changed from A/ to C/, following the receipt of the following message from M. Micheli: "We obtained two 60-secondr-fi ltered exposures of A/2018 C2 using the Canada-France-Hawaii Telescope on2018 March 22.6 UT. The queue observer was David Woodworth.  The object iscometary, displaying a broad faint tail of about 10" toward the West. The comais only marginally extended, with a FWHM of 0.9" compared to 0.8" of nearbystars." (ref. M.P.E.C. 2018-F136).

- Comet Recoveries

Jan 17  Recovery of P/2013 CU_129 (PANSTARRS) as P/2018 A2
Mar 22  Recovery of P/2005 JN (SPACEWATCH) as P/2018 F2

- Other news

Jan 5  RIP Thomas J. Bopp (1949-2018), co-discoverer of comet Hale-Bopp in 1995 (with Alan Hale).

Jan 24 Radar images of near-Earth asteroid 2018 AJ  by @AreciboRadar show an elongated body, about 60m x 120m with a considerable brightness variations as it rotates every 45 minutes.

Credit Arecibo/NASA/NSF

Feb 02 New paper on Arxiv by Kim et al.: "Orbital Alignment of Main-Belt Comets". 

Feb 05 RIP Yoshihide Kozai (1928 - 2018), Japanese astronomer specialising in celestial mechanics. He is best known for discovering, simultaneously with Michael Lidov, the Kozai mechanism, for which he received the Imperial Prize of the Japan Academy in 1979.

Feb 08 3.79 billion miles from Earth, New Horizons snapped these images of a pair of Kuiper Belt objects, making them the farthest images ever taken by a spacecraft

"These December 2017 false-color images of KBOs 2012 HZ84 (left) and 2012 HE85 are, for now, the farthest from Earth ever captured by a spacecraft. They're also the closest-ever images of Kuiper Belt objects".


Feb 09 Image & Animation of @SpaceX "2018-017A" a.k.a. #Starman #TeslaRoadster #FalconHeavy #astronomy #spacex. Click on the thumbnails below for a bigger version.

Feb 13 Recent radar images of near-Earth asteroid (505657) 2014 SR339 from @NAICobservatory show a lumpy, elongated body at least 1.5 km long and rotating once every 8 to 9 hours.

Credit Arecibo/NASA/NSF

Feb 21 Radar images of asteroid (3752) Camillo on Feb. 21, 2018 via @AreciboRadar & @NAICobservatory: "Optical observations suggested an elongated body with a slow rotation, but radar reveals an unexpectedly angular, double-lobed shape seen in very few near-Earth asteroids".

Credit Arecibo/NASA/NSF

Mar 05 New paper on Arxiv by Ariel Graykowski & David Jewitt: "Colors and Shapes of the Irregular Planetary Satellites".

Credit Graykowski & Jewitt

Mar 07 Radar images of asteroid "2017 VR12" on March 06, 2018 via @AreciboRadar & @NAICobservatory: "The asteroid is clearly elongated, yet angular, with about 100 to  160 meters visible as it rotates once every 1.4 hours".

Credit Arecibo/NASA/NSF

Mar 14 New paper on Arxiv by Reddy et al.: "Surface Composition of (99942) Apophis".

Credit: Reddy et al.

by Ernesto Guido

Friday, March 23, 2018

Bright Transient in Carina

Following the posting on the ATel #11454 about the discovery by All Sky Automated Survey for SuperNovae survey (ASAS-SN) of a new transient source, possibly a classical nova, near the Galactic plane in Carina (ASAS-SN Designation: ASASSN-18fv) I performed some follow-up of this object through a 0.43-m f/6.8 astrograph + CCD from MPC Code Q62 (iTelescope Observatory, Siding Spring).

On images taken on March 23.4, 2018 I can confirm the presence of an optical counterpart with R-filtered CCD magnitude +5.7 at coordinates:

R.A. = 10 36 15.42, Decl.= -59 35 53.7

(equinox 2000.0; UCAC-4 catalogue reference stars).

Below you can see my confirmation image (single 20-sec exposure through a 0.43-m f/6.8 astrograph + CCD), click on it for a bigger version:

While below you can see a wide-field color image (90 second exposures) I obtained on March 23.4, 2018 through a Takahashi SKY90 Apochromatic Refractor f5/6 + Color CCD. In the image ASASSN-18fv is visible at the centre of the field together with part of the Carina Nebula (click on it for a bigger version):

This transient was discovered using data from the quadruple 14-cm "Cassius" telescope in CTIO, Chile of ASAS-SN survey on images obtained on UT 2018-03-20.32 at V<10 2018-03-16.32="" also="" asas-sn="" asassn-18fv="" at="" detected="" detection="" no="" on="" possibly="" saturated="" starting="" ut="" v="">17.0) of this object in subtracted images taken on UT 2018-03-15.34 and before by the same survey. No previous outbursts or variability are detected at the position of ASASSN-18fv since ASAS-SN started observing this location in February 2016. 

According to Atel #11467 pre-discovery images have been identified on images obtained by Evryscope-South, an array of 6-cm telescopes continuously monitoring 8000 square degrees of sky at 2-minute cadence from CTIO, Chile. The transient is not detected at UT 2018-03-16.0316 with an upper-limit of 11.9 +/- 0.1 mag (g'). Beginning at UT 2018-03-16.227, they detected a new source at 10.21 +/- 0.05 mag (g'). (click on the images below for a bigger version).

Credit: Evryscope
Credit: Evryscope

An animation showing a comparison between my confirmation image and the archive POSS2/UKSTU Red plate (1991-02-10). Click on it for a bigger version:

Spectroscopy by  P. Luckas (see ATel #11460) seems to indicate that ASASSN-18fv is a classical nova brightening and in the optically thick (Fe curtain) phase. 

But according to L. Izzo et al. (ATel #11468): "The lack of a strong blue continuum, that is however typical of classical nova outburst, and the low expansion velocities suggest a possible different nature for this object. The presence of many narrow absorptions also suggests a similarity with other peculiar explosions, like the luminous red variable V4332 Sgr (Martini et al. 1999), the possible luminous red novae V838 Mon and V1309 Sco (Tylenda et al. 2011, Mason et al. 2010) or the 'helium-flash' explosion observed in the Sakurai object (Duerbeck and Benetti 1996)". Doubts about the nova nature of this object were expressed also by J. Strader et al. (ATel #11456)

So further spectroscopic observations are important to clarify the nature of this very interesting transient.

by Ernesto Guido

Monday, March 19, 2018

New Comet: C/2018 E1 (ATLAS)

CBET nr. 4494, issued on 2018, March 16, announces the discovery of an apparently asteroidal object (magnitude ~17) in the course of the "Asteroid Terrestrial-impact Last Alert System" (ATLAS) search program on CCD images obtained with a 0.5-m f/2 Schmidt reflector at Haleakala, Hawaii. Posted on the Minor Planet Center's PCCP webpage, it has been reported as showing cometary activity by CCD astrometrists elsewhere. The new comet has been designated C/2018 E1 (ATLAS). 

I performed follow-up measurements of this object, while it was still on the PCCP webpage. Stacking of 5 unfiltered exposures, 60 seconds each, obtained remotely on 2018, March 12.4 from Q62 (iTelescope network) through a 0.70-m f/6.6 reflector + CCD, shows that this object is a comet with a diffuse coma about 5 arcsec in diameter. The FWHM of this object was measured about 20% wider than that of nearby field stars of similar brightness.

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

"Pre-discovery" Panstarrs observations (2015 & 2016) were identified by R. Weryk. M.P.E.C. 2018-F10 assigns the following elliptical orbital elements to comet C/2018 E1: T 2018 Apr. 17.3; e= 0.95; Peri. =  299.47; q = 2.70;  Incl.= 72.48

by Ernesto Guido

Friday, February 9, 2018

Image & Animation of "2018-017A" a.k.a. #Starman

On February 06, 2018 at 20:45 UT, SpaceX successfully launched the Falcon Heavy, a reusable super heavy-lift launch vehicle, introduced as the most powerful rocket currently in operation.

The dummy payload for this test flight was a sports car owned by SpaceX CEO Elon Musk, a midnight cherry, first generation Tesla Roadster. It was selected as "something fun and without irreplaceable sentimental value" to be launched into space on the maiden flight of the Falcon Heavy rocket. The purpose of including the Roadster on the maiden flight was to demonstrate that the Falcon Heavy can launch payloads as far as the orbit of Mars.

Sitting in the driver's seat of the Roadster is "Starman", a dummy astronaut clad in a SpaceX spacesuit. He has his right hand on the steering wheel and left elbow resting on the open window sill. Starman is named for the David Bowie song "Starman". The car's sound system was looping the symbolic Bowie songs "Space Oddity" and "Life on Mars?". A copy of Douglas Adams' 1979 novel "The Hitchhiker's Guide to the Galaxy" is in the glovebox, along with a towel and a sign on the dashboard that reads "Don't Panic!" (two references to the book).

Credit: Spacex

On February 09.4, 2018 I performed follow-up of the #Starman #TeslaRoadster (officially designated 2018-017A) remotely from MPC code H06 (Mayhill, New Mexico; iTelescope network) through a 0.25-m f/3.4 reflector + CCD. Click on the image below for a bigger version.

While below you can see a short animation showing the motion of Starman in about 20 minutes. Each frame is a 60-second exposure. North is up, East to the left.

In the hours after the successful Falcon Heavy launch, a live video feed of the Roadster and Starman from three cameras mounted inside and on booms attached to the outside of the vehicle was broadcast on YouTube. It was expected to last for about twelve hours until the on-board batteries were depleted; however, the livestream lasted for just over four hours. Full video stream of the car as it creates spectacular views of Earth from space is still available, see Youtube video below.

By Ernesto Guido

Thursday, February 8, 2018

Comets & Asteroids - Summary Aug through Dec 2017

During the 5-month period Aug through Dec 2017, 22 new comets were discovered, cometary activity was detected for 5 previously discovered object (earlier designated as an asteroid) and there were 5 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

Aug 17 Discovery of P/2017 P1 (PANSTARRS)
Aug 23 Discovery of C/2017 P2 (PANSTARRS)

Sep 22 Discovery of P/2017 R1 (PANSTARRS)
Sep 22 Discovery of C/2017 S2 (PANSTARRS)
Sep 27 Discovery of C/2017 S3 (PANSTARRS)
Sep 29 Discovery of P/2017 S5 (ATLAS)

Comet P/2017 S5 - Credit: ATLAS survey

Oct 08 Discovery of C/2017 S6 (CATALINA)
Oct 08 Discovery of C/2017 S7 (LEMMON)
Oct 16 Discovery of C/2017 T1 (HEINZE)
Oct 25 Discovery of C/2017 T2 (PANSTARRS)
Oct 28 Discovery of P/2017 S8 (PANSTARRS)
Oct 28 Discovery of P/2017 S9 (PANSTARRS)
Oct 28 Discovery of C/2017 T3 (ATLAS)
Oct 29 Discovery of C/2017 U2 (FULS)

Nov 13 Discovery of P/2017 U3 (PANSTARRS)
Nov 20 Discovery of C/2017 U4 (PANSTARRS)

Dec 03 Discovery of C/2017 U5 (PANSTARRS)
Dec 19 Discovery of C/2017 W2 (LEONARD)
Dec 19 Discovery of P/2017 W3 (GIBBS)
Dec 19 Discovery of C/2017 X1 (PANSTARRS)
Dec 31 Discovery of C/2017 Y1 (PANSTARRS)
Dec 31 Discovery of C/2017 Y2 (PANSTARRS)

- Cometary activity detected

Aug 03 Following the announcement on CBET 4415 of the possible connection of 2017 MB_1 and the alpha Cap meteor shower, P. Birtwhistle, Great Shefford, Berkshire, England, re-examined his CCD images of 2017 MB_1 taken using a 0.40-m Schmidt-Cassegrain reflector on several dates. There are no traces of cometary activity on co-added exposures taken on July 4.04 (10 min exposure time) and 5.04 UT (30 min total exposure), but on July 25.11, stacked exposures totalling 7.2 min show a possible very faint, thin, straight tail in p.a. 260 deg, appearing detached from the main object, starting at a distance of 35" and extending to 90" from 2017 MB_1. The images from July 25 were taken in brightening nautical twilight (solar altitude -12.8 to -12.0 degrees), but he is reasonably confident that the possible tail is real and not an artifact.

Aug 11 Cometary activity detected in the NEOWISE images containing minor planet 2014 XK_6

Aug 25 Cometary activity detected in 2007 RS_41 = P/2017 Q2 (LONEOS)

Sep 28 Cometary activity detected in 2006 UR_111 (SPACEWATCH) = P/2017 S4

Dec 13 Cometary activity detected in 2000 XO_8

- Comet Recoveries

Aug 03  Recovery of P/2010 D1 (WISE) as P/2017 O2
Aug 22  Recovery of P/2008 T4 (HILL) as P/2017 Q1
Aug 26  Recovery of P/2012 T1 (PANSTARRS) as P/2017 O3
Sep 20  Recovery of P/2010 P4 (WISE) as P/2017 S1
Nov 20  Recovery of P/2011 VJ_5 (LEMMON) as P/2017 W1

Oct 09 CBET 4442 reports that the following name has been voted upon by the IAU Working Group on Small Body Nomenclature for a recently discovered comet:

Designation (Name)                     Discovery Reference
351P/Wiegert-PANSTARRS             CBET 4439*
C/2017 O1 (ASASSN)                     CBET 4414

* Further to CBET 4298, G. V. Williams (Minor Planet Center) has linked a reported comet from 2007 to comet P/2016 P2. The comet has been given the permanent number 351P and year designations P/2016 P2 = P/1998 U8 = P/2007 R11.

Further to CBETs 4376 and 4439, 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
352P/Skiff                     P/2000 S1 = P/2017 L1                    CBET 4402
353P/McNaught            P/2009 S2 = P/2017 M1                   CBET 4404
354P/LINEAR              P/2010 A2 = P/2017 B5                    CBET 4405
355P/LINEAR-NEAT     P/2004 T1 = P/2017 M2                   CBET 4406
356P/WISE                   P/2010 D1 = P/2017 O2                    CBET 4441
357P/Hill                       P/2008 T4 = P/2017 Q1                    CBET 4422
358P/PANSTARRS       P/2012 T1 = P/2017 O3                    CBET 4425
359P/LONEOS              P/2007 RS_41 = P/2017 Q2             CBET 4424
360P/WISE                    P/2010 P4 = P/2017 S1                    CBET 4429
361P/Spacewatch          P/2006 UR_111 = P/2017 S4            CBET 4433
362P/(457175)              P/2008 GO_98                                   CBET 4411

- Other news

Aug 06 Asteroid 2012 TC4 has been recovered. Close approach on Oct. 12 at ~50200 km. Images from 2012 available here while images & animation of Oct. 2017 close approach are available here.

Aug 17 New paper on Arxiv by Jian-Yang Li et al. : "The Unusual Apparition of Comet 252P/2000 G1 (LINEAR) and Comparison with Comet P/2016 BA14 (PanSTARRS)"

Sep 01 Goldstone Radar Images of asteroid (3122) Florence. Florence will approach  within 0.047 AU on 2017 September 1 (FOTO). Radar Reveals Two Moons Orbiting Asteroid Florence.

Credit: Goldstone

Sep 16 New paper on Arxiv by Snodgrass et al. : "The Main Belt Comets and Ice in the Solar System"

Sep 20 NASA’s Hubble Space Telescope helped an international team of astronomers find that an unusual object in the asteroid belt is, in fact, two asteroids orbiting  each other that have comet-like features. These include a bright halo of material,  called a coma, and a long tail of dust. The time-lapse video below, assembled from a set of Hubble Space Telescope photos, reveals two asteroids orbiting each other that have comet-like features. The asteroid pair, called 2006 VW139/288P, was observed in September 2016, just before the asteroid made its closest approach to the Sun.

Credits: NASA, ESA, and J. DePasquale and Z. Levay (STScI)

Sep 29 NASA's Hubble Observes the Farthest Active Inbound Comet Yet Seen  - Paper by Jewitt et al. available here.

Credits: NASA, ESA, and D. Jewitt (UCLA)

Oct 04 CBET 4435, CBET 4436, CBET 4440 (Oct.09) & CBET 4459 (Dec. 08) report that the following minor planets are binaries systems: 2017 RV1; (23621) 1996 PA; (10132) LUMMELUNDA; (3378) SUSANVICTORIA

Oct 11 New paper on Arxiv by Meech et al: "CO-Driven Activity in Comet C/2017 K2 (PANSTARRS)"

Oct 25 The first clear case of an interstellar object A/2017 U1. According to CBET 4450 "inadvertently designated as comet C/2017 U1 on MPEC 2017-U181 (and changed to A/2017 U1) with no claimed cometary appearance by anyobservers appears to have hyperbolic orbital elements". A/2017 U1 was discovered Oct. 19 by the University of Hawaii's Pan-STARRS 1 telescope on Haleakala during the course of its nightly search for Near-Earth Objects for NASA. appears to have originated from outside the solar system, coming from somewhere else in our galaxy. If so, it would be the first "interstellar object" to be observed and confirmed by astronomers. According to MPEC 2017-V17: "the object A/2017 U1 receives the permanent designation 1I and the name ʻOumuamua.  The name, which was chosen by the Pan-STARRS team, is of Hawaiian origin and reflects the way this object is like a scout or messenger sent from the distant past to reach out to us (ʻou means reach out for, and mua, with the second mua placing emphasis, means first, in advance of). Correct forms for referring to this object are therefore: 1I; 1I/2017 U1; 1I/ʻOumuamua; and 1I/2017 U1 (ʻOumuamua).

Oct 27 Comet 96P/Machholz in the LASCO C3 camera on ESA/NASA SOHO.

Credit: SOHO

Dec 08 New Outburst of 174P/Echeclus


Dec 22 Radar images of asteroid (3200) Phaethon via Arecibo Radar

by Ernesto Guido