(personal website)| Asteroid
(183294) Langbroek | Naming
citations page |
Blink image of the discovery triplet showing 2002 NX57, my first discovery (images by NEAT).
In 2004 I started my search for asteroids as a volunteer plate reviewer in the Spacewatch FMO Project (which ended in 2006) and discovered the Amor asteroid 2005 GG81. Around the same time I started my search for Main Belt Asteroids & Trojans in the NEAT archives. Early 2009, after 57 discoveries, I stopped hunting in the NEAT archives.
Currently I am a volunteer in the Piszkéstető (Konkoly, HU) survey for NEA's, comets and Main Belt asteroids since the second half of 2012, resulting in one NEA (2015 CA40) and a number of main belt discoveries. In addition I am finding new Main Belt asteroids by making "remote" use of the telescopes in the SSON network.
I do follow-up on recently discovered NEO's by 'remote' use of the telescopes in the SSON network (e.g. here and here), as well as additional astrometry on main belt objects we encounter in the Konkoly survey.
Spacewatch ran a public participation program from 2003 to 2006, the now discontinued Spacewatch FMO Project, which I joined in January 2004. On 9 April 2005 I discovered my first NEA in this project, 2005 GG81. The discovery was made together with Jim Scotti and Tim Bressi, who manned the telescope that night. The discovery was announced on 11 April 2005 in MPEC K05G73. Our initial internal designation for the object was SW40LW.
2005 GG81 is an Amor
class asteroid of approximately 30 meter wide, which can
come to within 0.053 AU of the Earth. Because of its small size, it
needs to be close to earth to be detected again. The first occasion
when that might be possible, will be near 6 April
2051 (see diagram below), when the asteroid might come as close as 0.09
AU again (compare to 0.06 AU for the discovery encounter in 2005).
Perhaps I might live to see that happen.
Orbit of the small Amor asteroid 2005 GG81, which I discovered (with J. Scotti and T. Bressi) in the Spacewatch FMO project on 9 April 2005
Approaches to Earth for 2005 GG81 in future years
A Near Earth Asteroid (NEA) with the Piszkéstető (Konkoly) survey
(see table I)
Monday 16 February 2015 I discovered a NEA, 2015 CA40, in images taken by Krisztián
Sárneczky on the night of Feb 15-16 with the 0.6-meter Schmidt of MPC 461 Piszkéstető
(Konkoly) in Hungary. Our initial designation of this object was
SaLa122. The discovery was announced on 17 February 2015 in MPEC K15D10. The story of the discovery is detailed here.
above: One of the discovery images of 2015 CA40
is a borderline Amor/Apollo asteroid with perihelion just outside earth
orbit at 1.004 AU and aphelion between Mars and Earth at 1.20 AU. With H=24.7 the asteroid is estimated
to be about 40 meters wide. It
has an orbital inclination of 15.02 degrees and an orbital period of
1.16 years. The MOID is 6 lunar distances (0.0155 AU). On Feb 23-24,
2015 it made a close approach to 6.3 lunar distances. The next similar close
approach will be on 23 Feb 2066.
Above: 2015 CA40 in the morning of 24 Feb 2015 near 9 UT, some 12 hours after closest approach. Images taken overr a 10-minute timespan at 2 minute intervals and 30 second exposure with the 0.61-m F/10 Cassegrain of MPC G68 Sierra Stars Obs. in California, USA
Below: Orbit of 2015 CA40 (orbital position for moment of discovery, Feb 15 2015)
Distance of 2015 CA40 to earth for the coming century. Note the close approach in 2066
The Piszkéstető (Konkoly, HU) survey
(see table III)
In the summer of 2012 I joined the Piszkéstető (Konkoly, HU) asteroid survey of Dr. Krisztián Sárneczky as a volunteer plate reviewer, looking (by visual inspection of the images) for objects that have been missed by the automated plate inspection routines. The survey makes use of the Konkoly Mountain Station (Hungary) 60 cm Schmidt telescope. This work is usually done in the evening hours. My first discoveries in this survey were done during the October 2012 run. In February 2015, I discovered a NEA as part of this survey: 2015 CA40.
Main belt discoveries with the 61-cm SSON
(MPC G68) telescope
In 2010 I started to make "remote" use of the MPC G68 SSON 61-cm telescope in California, the MPC 857 Rigel IRT 37-cm telescope in Sonoita, Arizona and more recently the MPC G84 81-cm Mt. Lemon Sky Center Schulman telescope in Arizona. Using these telescopes I regularly do follow up astrometry on recent NEA discoveries.
In September 2012, I more or less by accident made my first asteroid discovery while "remotely" using these telescopes: 2012 SM58, discovered using the 61-cm telescope of MPC G68 of Sierra Stars Observatory, Markleeberg, CA, USA, while attempting to reocover a NEOCP object.
In April 2013 I appeared to have discovered 2013 GM21 using the 81-cm Schulman telescope of Mt. Lemon Sky Center (G84) in Arizona, USA. I found it while I was targetting one of our Piszkéstető (Konkoly, HU) survey objects for follow-up astrometry. 2013 GM21 just happened to be in the imaged field as well!
No earlier observations than my Apr 6, 2013, observations of 2013 GM21 were given by the MPC untill the second half of May 2013, when suddenly two sets of two-night observations from 2002 (NEAT) and 2006 (Spacewatch) popped up. At that point, it seems I "lost" the discovery!
Discovery images of 2012 SM58 (MPC G68 SSON 61-cm telescope), 21 Sep 2012
Follow-up images from 17 October 2012 (MPC G84 Mt. Lemon 81-cm telescope)
Between 2004 and early 2009 I have found 54 new
main belt asteroids
Jovian Trojans in NEAT archive images. Of these, 41 have now
been assigned permanent
numbers (38 main
belts, 3 Trojans; see list below) and seven
have been given names.
NEAT discoveries were made in archived imagery of NASA's NEAT
searches for Near Earth Asteroids. Their imagery contained numerous
belt asteroids, missed by the automated plate routines. In the
mid-2000's it was a sports to hunt for these faint uncatalogued
main belt asteroids in the images. The trick was to obtain enough
positions on enough nights
to get a
designation for them from the IAU Minor
Planet Center. This
involved finding, astrometrically measuring and following the
same object in imagery from multiple
nights (see link in section useful information
below) untill a linked set of observations spanning several nights was
obtained. That sounds easy, but isn't.
The objects discovered were typically in the magnitude +19.5 to +21 class in the discovery images, and typically have (estimated) real sizes near 1-2 km diameter. The Trojans are somewhat larger (up to 7-9 km diameter).
My discoveries classified into
groups and families (last update 9 March 2013)
first discovery was 2002
I discovered it
on 27 August 2004 in NEAT archive images from July and August 2002. A
of other discoveries followed, 58 in total. In 2008, I discovered my
first Jovian Trojans,
a special group of asteroids moving in the orbit of Jupiter, in
Jupiter's Lagrange points L4 and L5. A full list of discoveries is
(due to increased competition form other surveys) it became more and
more difficult to find new objects in NEAT imagery, and
attention shifted to actually timely imaging asteroids myself using
"remote" telescopes, I stopped hunting the NEAT archives in 2009.
Discovery credits & discoveries list
My discoveries list now counts over 60 objects. Prior to 2010, a "discovery" meant that you had supplied the MPC with positions for the object at at least two (and preferably more) nights, not too far (i.e. not more than a few days) apart. Single Night detections did not count. Currently, per new MPC rules single night detections do often count as a discovery, provided there is a second detection made that same opposition. This need not necessarily be a detection by the same observatory, project or discoverer!Below is a list of my discoveries so far, according to the rules applying at the time in question and an additional personal rule that a discovery has to be MPEC-ed for me personally to count. Efemerids and/or orbital elements for these objects can be retrieved here.
I got full formal credits for my discovery of 2005 GG81 while a volunteer plate reviewer with Spacewatch, being listed as an 'observer' in the MPEC. Hence, my Spacewatch discovery is an official discovery. Likewise, my discoveries made while "remotely" using the SSON telecopes and my discoveries with Krisztián Sárneczky as part of the Konkoly survey are official discoveries (albeit provisional, as discovery credits sometimes change when the MPC manages to link the object to earlier detections by other observatories after some time).
With NEAT, it is slightly different. After 2003,
formal credits for discoveries in the
NEAT archives go to the NEAT team and not to the person finding the
object in the NEAT imagery and submitting the linked astrometry (they
used to in the past). The
personal NEAT 'discovery' count on this page
therefore is a semi-official one similar to the habit of SOHO comet
The NEAT-team has been very willing to go along with naming suggestions for main belt objects I discovered in their data in 2004-2009 now bearing a permanent number. Four got named Miskotte, Neirinck, Rietmeijer and Kürti at my suggestion in 2008, one got named Dubois in 2009 and two got named Jobse and Binford in 2010. The naming citations for these asteroids as published in the Minor Planet Circulars can be read here.
August 2008, the International Astronomical Union named an asteroid
after me: asteroid (183294)
Langbroek. Read more about it here.
2012 Dr J. Van der Bilt Prize
In November of 2012, the Royal Dutch Astronomy Association (KNVWS) awarded me their Dr J. Van der Bilt Prize for my work on Asteroids, Meteors and Artificial Satellites. Read more about it here.
As is customary, after the award ceremony at the KNVWS Astrodag in Goirle on November 10, 2012, I performed a lecture on my activities, focussing on my asteroid work. The following YouTube video's below show you this full lecture (each part is about 20 minutes), and are in Dutch, not English:
A guide to using the Skymorph NEAT archives for discovery and precovery work can be found here. A follow-up ephemerides page for those who want to do follow-up astrometry on the objects I discovered to help improve their orbits, can be found here.
Acknowledgement is made to Jeff Brower for introducing me to the Spacewatch FMO Project, and especially to Rob Matson for introducing me to the techniques of hunting in the NEAT archives using Skymorph and Astrometrica. I thank Krisztián Sárneczky for involving me in the Konkoly survey, and Stefan Kürti for our continuing and much appreciated cooperation. Astrometry on asteroids is done with Herbert Raab's excellent Astrometrica software. I thank the people of NEAT for their cooperation in naming several of the asteroids with a permanent number.
NOTE: Only MPEC-ed discoveries are listed
obj. design. discovered MPEC type q (AU) e MOID (AU)
Discovery (official) in the MPC 461 Piszkéstető (Konkoly) survey (Near Earth Asteroid) - with Krisztián Sárneczky
obj. design. discovered MPEC type q (AU) e MOID (AU)
Discoveries (provisional) using the MPC G68 61-cm SSON telescope (Main Belt asteroids) 2012 - current:
obj. design. number name discovered MPC Nts arc subm. MPEC Group
LaMa502 2012 SM58 21-09-2012 G68 5 21/9-17/10 K12T11 MB IIb
Note: if you find and submitt precovery imagery of the objects above, please let me know via
asteroids |at| langbroek dot org
Discoveries (provisional) with Krisztián Sárneczky, MPC 461 Piszkéstető (Konkoly) survey
(Main Belt asteroids) 2012 - current:
(note: listed discoveries are provisional and this table will be occasionally revised, with objects removed when links with earlier observations pop up. The final discovery credit for post-2010 discovered objects is now only assigned by the MPC upon permanent numbering and under new rules compared to pre-2010 discoveries. Some asteroids in this table might therefore eventually be assigned to another observatory. Hence these discoveries are provisional only)
obj. design. number name discovered MPEC GroupSaLa002 2012 UK98 06-10-2012 K13E30 MB IIb
SaLa007 2012 TD101 08-10-2012 K12X24 MB IIb
SaLa011 2012 UQ140 11-10-2012 K13A11 MB IIIa
SaLa012 2012 TU254 11-10-2012 K12U43 Flora
SaLa017 2012 UL146 11-10-2012 K12V06 MB IIb
SaLa045 2013 DJ15 21-02-2013 K13E02 Hungaria
SaLa073 2013 XW4 01-12-2013 K13X46 MB IIIb
SaLa089 2014 SB321 29-09-2014 K14UB6 Flora
SaLa092 2014 UP223 20-10-2014 K15B82 Phocaea
obj. design. number name discovered disc image Nts arc subm. MPEC a (AU)
ML023A 2001 SD355 283510
10 2001-2002 K08W84 5.16
obj. design. number name discovered disc image Nts arc subm. MPEC Group
LAMA77 2002 PC168 14-10-2004 30-8-2002 5 11/8-15/9 K04T71 MB I
2002 BF32 427496
18-11-2006 21-1-2002 3
20/1-22/1 K06WA3 Maria
2002 VK143 357300
31/10-22/11 K09C20 MB IIb
3 24/11-10/12 K09F67 MB IIa
Page allowing to retrieve Osculating orbital elements and/or search Ephemerides for these objects (source: MPC)
discoveries (status 14 Sep 2015): 69
Near Earth Asteroids: 2
- Tables only list MPEC-ed discoveries (i.e. multiple night objects);
- Post-2010 objects (Konkoly survey) with provisional designations are provisional discoveries, as final discovery credits are assigned only at the time of final numbering;
- SW40LW while participating in the Spacewatch FMO project, with J. Scotti and T. Bressi;
- SaLa objects with Krisztián Sárneczky, as part of the Piszkéstető (Konkoly) survey;
- LAMA04, ML009A together with Rob Matson;
- NEAT discoveries were in archive imagery: all the others were in timely near-real-time imagery
Positions of the asteroids I discovered (last updated 10 May 2013)
Discovery credit rules per October 2010 (MPC website)