OT: Near Earth Asteroid 2012 LZ1 fly-by imaged, June 15

On June 10, 2012, Australian Siding Spring astronomer Rob McNaught and colleagues discovered a bright Near Earth Asteroid (NEA). It got the provisional designation 2012 LZ1 and turned out to be large: it is estimated to be about 500 meter in diameter (UPDATE 22 June 2012: radar observations from Arecibo obtained during the fly-by actually showed it to be twice as large, i.e. 1 km diameter! This suggests a low albedo, which might imply a carbonaceous composition). It made it's closest approach to the earth/moon system around midnight of June 14/15. With a pass distance of 5.3 million km (a multitude of the Earth-Moon distance), this flyby was not particularly close. But because the asteroid is large, it became quite bright, ~ mag. +13.

In the early morning of June 15, some 9 hours after closest approach, I used the "remote" 37-cm F/14 Cassegrain of UoI Rigel observatory at Sonoita, Arizona, USA (MPC 857, the same telescope that I often use to image geostationary satellites)  to image the asteroid (I also obtained some imagery using the larger 61-cm telescope of Sierra Stars Observatory in California).

click image to enlarge

The image above is a stack of 4 CCD images, each of 30 second exposure and spaced 5 minutes in time, obtained with the Rigel telescope. The asteroid can be seen as a set of 4 short trails lining up. It was moving at a rate of about 35"/minute near the Aquila-Capricorn border at that time and was near mag. +13.

Another close encounter of a rocky kind....: 2005 YU55

Half a year after the close approach of asteroid 2011 MD (see my images here and here), another one whizzed by the Earth last night. It was 2005 YU55, a 400-meter wide asteroid discovered in 2005 by Spacewatch. It came to within 0.85 lunar distances at 23:28 UT (Nov 8, 2011), with a maximum brightness near +11.

click image to enlarge

Four hours after closest approach, I made the image above, using a "remote" 61-cm F/10 Cassegrain telescope at Sierra Stars Observatory (MPC G68). It is a 30 second exposure starting at 03:21:41 UT (9 Nov 2011), during which the asteroid (moving from right to left) has trailed considerably.

Astrometry from my images has been included in MPEC 2011-V34 (the G68 observations at

09.11922, 09.14006 and 09.32778).

OT: more imagery of the earthgrazing asteroid 2011 MD

Like yesterday, I used the 0.61-meter F/10 Cassegrain of Sierra Stars Observatory (G68) in California again to image the earthgrazing asteroid 2011 MD, this time a few hours after closest approach.

Below animated GIF was made from three 30 second exposures, spaced 30 seconds, starting at 09:35:01 UTC (28 June).

OT: Close Encounters of a Rocky Kind (2011 MD)

Today, a small asteroid, 2011 MD, made a very close pass by the earth, coming to within a distance of 12,400 km at about 13:30 UTC (June 27). That is well within the distance of geostationary satellites, and even within the distance of GPS satellites in MEO!

This morning, some 5 hours before closest approach, I used the 0.61-meter F/10 Cassegrain of Sierra Stars Observatory (G68) in California, to capture this PHA earthgrazer.

click image to enlarge

This image is a 30 second CCD exposure taken between 08:32:00 and 08:32:30 UTC (June 27, 2011). In these 30 seconds, the fast moving object left a notable bright trail on the image. Star field is in Serpens, image center approximately RA 15h35m57s, dec. +19.441 degrees.

UPDATE: more of my 2011 MD imagery shot on the 28th here.

My third Trojan asteroid

As the weather did not allow observations the past week, some news from my asteroid searches. Whenever I want something to do in the evening and it is clouded (so I can't observe satellites) and the TV is dull -which it usually is-, I turn to hunting for new uncatalogued asteroids in NEAT archive imagery.

Today's DOU MPEC 2009-B61 contains four of my new asteroid finds of last week. One of these, 2002 WG29, is a Jovian Trojan, my third Trojan discovery (the other two are 2001 SD355 and (203865) = 2002 WV27).

Jovian Trojans are asteroids that co-orbit with Jupiter in a 1:1 mean motion resonance, as they occupy the stable Lagrange points L4 and L5 in the Jupiter orbit. They are hence a quite special class of asteroids. Currently, some 2900 of these Trojans (including those with temporary designations) have been discovered. Their positions for late 2008 in the two Lagrange points at 60 degrees in front and behind of Jupiter are shown below:





Among the other discoveries of last week are two Hungaria asteroids. Hungaria asteroids are a special class as well: they occupy higher inclinations within 2.0 AU, a region in the main asteroid belt where at lower inclinations a stable orbit isn't possible due to perturbations by Mars. Hungaria's move in a 9:2 mean motion resonance with Jupiter and a 3:2 mean motion resonance with Mars. Hence, they quite stand out among the main belt asteroid population.

Below are two plots showing the positions in the solar system of the objects I discovered for coming February 1st. The new Trojan is the one currently just outside Jupiter's orbit in the top plot.

A full list of my asteroid discoveries can be found here.

(click images to enlarge)

Bad weather

Bad weather and midwinter situations leading to only a very short observation window right after dusk are the main reasons why observing has come to a stop at the moment. I haven't been able to observe since November 29th, which itself was preceded by a period of forced non-observation due to the weather.

This means I spent some time hunting asteroids again in archive imagery of the NEAT project. It was (and is) a rather prolific stint of asteroid hunting, yielding the following new designations (with a few datasets still pending):

tmp. desig.
2002 PN188
2002 WQ27
2001 SD355
2002 WR27
2002 XK118
2002 UU76
2002 WV27
2002 WW27
2002 WX27

For a complete list of my discoveries, see here.

Two of the new discoveries (2001 SD355 and 2002 WV27) are Jovian Trojans moving in the L4 and L5 Lagrange points of Jupiter, 60 degrees on either side of it, sharing the planet's orbit. It are my first trojan discoveries.

In total I now discovered one Near Earth Asteroid (in the Spacewatch FMO program) and (in the NEAT archives) two Trojans and 22 main belt asteroids.

Asteroid (142014) Neirinck

Today, it was my pleasure to announce to Pierre Neirinck that the IAU has approved this new asteroid name:

(142014) Neirinck

The naming citation published in the Minor Planet Circulars, reads:

(142014) Neirinck = 2002 PA168 Discovered 2002 Aug. 8 by NEAT at Palomar.
French-born Pierre Neirinck (b. 1926) headed the Satellite Orbits Group at Appleton Laboratory in the U.K. during the 1970s. Now retired, he still coordinates the international amateur satellite observations. The name was suggested by M. Langbroek.

Pierre Neirinck is a veteran satellite observer and analyst. As an active French observer from the dawn of the space age, he was recruited by the British satellite research analyst Hele-King, and headed the British Orbital Analysis Group from the early seventies until his early retirement. Now 82 years old, he still actively observes, and coordinates amateur satellite observations. He provides new Cospar designations to new observers, and daily sends bulletins updating the orbits of some of the more interesting satellites (notably the KeyHoles). His daily reports are a delight to read, not only because of the orbit analysis, but also because they always contain an ironic, sometimes even cynic commentary on current affairs in this world. Amongst others, he keeps a dedicated tally of the number of people that depart our planet in violent ways each day.

(142014) Neirinck was discovered by me in archived images of the NEAT project from 8 August 2002 (and surrounding nights) taken by the 1.2 meter Schmidt telescope of the project at Mount Palomar. With H=16.9, it is estimated to be about 1.5 kilometers in diameter. It completes an orbit around the sun each 3.8 years.

(click image to enlarge)

The same batch of MPC's contained three other new asteroid names suggested by me for objects I discovered:

(132820) Miskotte

132820 Miskotte Discovered 2002 Aug. 17 by NEAT at Palomar.
Koen Miskotte (b. 1962) is a Dutch confectioner and amateur astronomer whose main interests lie in meteor astronomy. He is a very prolific meteor observer, active within the Dutch Meteor Society. The name was suggested by M. Langbroek.

Koen is a very close friend of mine, and we have travelled the world and observed meteor showers together many times. He is a dedicated, extremely active meteor observer for many decades now, and has contributed data to several scientific meteor studies.

(179678) Rietmeijer

179678 Rietmeijer Discovered 2002 Aug. 26 by NEAT at Palomar.
Frans J.M. Rietmeijer (b. 1949) is a Dutch-born planetary geologist specializing on interplanetary dust particles. He is a research professor at the University of New Mexico. The name was suggested by M. Langbroek.

Frans, a renowned expert scientist on IDP's, is a close friend too, even though he lives at distance in New Mexico. We met 10 years ago through my meteor/meteorite related activities and soon developed a personal friendship. Whenever Frans is briefly in the Netherlands again we meet for a dinner. He has acted as my older & wiser mentor in science career related business.

(132798) Kürti

132798 Kürti Discovered 2002 Aug. 8 by NEAT at Palomar.
Stefan Kürti (b. 1960) is a Slovakian amateur astronomer with a focus on minor planets. Among his discoveries are two near-earth objects. The name was suggested by M. Langbroek.

Stefan was in the Spacewatch FMO project with me, and is an active asteroid hunter. He surprised me last summer by naming one of his finds after me.

Asteroid 183294 Langbroek!

This weekend, I got notified of the fact that the Committee on mall Body Nomenclature of the International Astronomical Union (IAU) has decided that asteroid 183294 (also know by its temporary designation 2002 TB382) will henceforth be officially named:

183294 Langbroek

The citation text from Minor Planet Circular # 63643:

(183294) Langbroek = 2002 TB382
Discovered 2002 Oct. 9 by NEAT at Palomar.
Marco Langbroek (b. 1970) is a Dutch archeologist and amateur astronomer whose main interests lie in meteor astronomy. He is an avid meteor observer, active within the Dutch Meteor Society. The name was suggested by S. Kürti.

Asteroid 183294 Langbroek is a main belt asteroid with an estimated 2.5 km diameter (H 15.6), has it's perihelion at 2.69 AU, aphelion at 3.39 AU and an orbital inclination of 6.34 degrees. It revolves around the sun once each 5.3 years, between the orbits of Mars and Jupiter. It was discovered on images taken 9 October 2002 with the 1.2 meter Schmidt telescope of the NEAT program at Mt. Palomar.

I feel very honoured by this asteroid naming.

Here's a blink of the discovery triplet, made on 9 Oktober 2002 with the NEAT 1.2m Schmidt telescope at Mt. Palomar:

Below is a plot of the orbit:

(click image to enlarge)

For an interactive orbit plot (JPL website), click here.