Palomar–Leiden survey

+ Minor planets discovered: 4637 see

The Palomar–Leiden survey (PLS) was a successful astronomical survey to study faint minor planets in a collaboration between the U.S Palomar Observatory and the Dutch Leiden Observatory, and resulted in the discovery of thousands of asteroids, including many Jupiter trojans.

The original PLS-survey took place in 1960, and was followed by three Palomar–Leiden Trojan survey campaigns, launched in 1971, 1973 and 1977. Its principal investigators were the astronomers Ingrid and Cornelis van Houten at Leiden and Tom Gehrels at Palomar. For the period of the entire survey (1960–1977), the trio of astronomers are credited with the discovery of 4,637 numbered minor planets, which received their own provisional designation, such as 6344 P-L, 4835 T-1 and 3181 T-2.

PLS was one of the most productive minor planet surveys ever conducted: five new asteroid families were discovered, gaps at 1:3 and 2:5 orbital resonances with Jupiter were revealed, and hundreds of photographic plates were taken with Palomar's Samuel Oschin telescope. These plates are still used in their digitized form for the precovery of minor planets today.

Summary

Approximately 5,500 minor planets were discovered during the Palomar–Leiden survey and its subsequent Trojan campaigns. A total of 4,622 minor planets have been numbered so far and are directly credited to the survey's principal investigators – Cornelis Johannes van Houten, Ingrid van Houten-Groeneveld and Tom Gehrels – by the Minor Planet Center (see ), which is responsible for the designation of minor bodies in the Solar System. Discoveries included members of the Hungaria and Hilda family, which are asteroids from the inner- and outermost regions of the asteroid belt, respectively, as well as a large number of Jupiter trojans.

P-L  Palomar–Leiden survey (1960), discovered more than 2,000 asteroids (1,800 with orbital information) in eleven nights. This number was increased to 2,400 including 19 Trojans after further analysis of the plates. A total of 130 photographic plates were taken. T-1   the first Palomar–Leiden Trojan survey (1971), discovered approximately 500 asteroids including 4 Jupiter trojans in nine nights. A total of 54 photographic plates were taken. T-2   the second Palomar–Leiden Trojan survey (1973), discovered another 1,200 asteroids including 18 Jupiter trojans in eight nights. A total of 78 photographic plates were taken. T-3   the third Palomar–Leiden Trojan survey (1977), discovered an additional 1,400 asteroids including 24 Jupiter trojans in seven nights. A total of 68 photographic plates were taken.

Naming

The discovered bodies received a custom provisional designation. For example, the asteroid 2040 P-L is the 2040th minor planet in the original Palomar–Leiden survey, while the asteroid 4835 T-1 was discovered during the first Trojan-campaign. The majority of these bodies have since been assigned a number and many are already named. The custom identifier in the provisional designation "P-L" stands for "Palomar–Leiden", named after Palomar Observatory and Leiden Observatory. For the three Trojan campaigns, the survey designation prefixes "T-1", "T-2" and "T-3" stand for "Trojan".

Surveys

The PLS was originally intended as an extension of the Yerkes–McDonald asteroid survey (1950–1952), which was initiated by Dutch–American astronomer Gerard Kuiper. While this survey was limited to a magnitude of up to 16, PLS could study minor planets up to a visual magnitudes of 20. However, it only covered a portion of the ecliptic about the vernal equinox, with the target areas selected to minimize the number of background stars.

Photographic plates taken by Tom Gehrels at the Lunar and Planetary Laboratory in Arizona using the 48-inch Schmidt camera at Palomar Observatory. The orbital elements were computed at the Cincinnati Observatory, which was the site of the Minor Planet Center at the time. All other aspects of the program were conducted at Leiden Observatory in the Netherlands.

Original PLS-survey

During September and October 1960, the first 130 photographic plates were taken, with each plate spanning and having a limiting magnitude of 20.5. The observed region covered an area of . The Zeiss blink comparator from the Heidelberg Observatory was adapted to perform blink comparison of the plates. This resulted in the discovery of a large number of asteroids; typically 200–400 per plate. A subset of these objects had sufficient data to allow orbital elements to be computed. The mean error in their positions was as small as 0.6, which corresponded to 0.009 mm on the plates. The resulting mean error in magnitude estimation was 0.19.

Trojan surveys

The third Palomar–Leiden Trojan survey was performed in 1977, resulting in the discovery of 26 Jupiter trojans. In total, there were three Trojan campaigns, designated T-1, T-2, and T-3, which discovered 3570 asteroids. Another small extension of the survey was reported in 1984, adding 170 new objects for a combined total of 2,403.

List of discovered minor planets

1743 Schmidt 24 September 1960 1744 Harriet 24 September 1960 1776 Kuiper 24 September 1960 1777 Gehrels 24 September 1960 1778 Alfvén 26 September 1960 1795 Woltjer 24 September 1960 1808 Bellerophon 24 September 1960 1809 Prometheus 24 September 1960 1810 Epimetheus 24 September 1960 1811 Bruwer 24 September 1960 1812 Gilgamesh 24 September 1960 1813 Imhotep 17 October 1960 1846 Bengt 24 September 1960 1868 Thersites 24 September 1960 1869 Philoctetes 24 September 1960 1870 Glaukos 24 March 1971 1871 Astyanax 24 March 1971 1872 Helenos 24 March 1971 1873 Agenor 25 March 1971 1912 Anubis 24 September 1960 1923 Osiris 24 September 1960 1924 Horus 24 September 1960 1964 Luyten 24 September 1960 1965 van de Kamp 24 September 1960 1966 Tristan 24 September 1960 1979 Sakharov 24 September 1960 2003 Harding 24 September 1960 2041 Lancelot 24 September 1960 2042 Sitarski 24 September 1960 2054 Gawain 24 September 1960 2082 Galahad 17 October 1960 2095 Parsifal 24 September 1960 2125 Karl-Ontjes 24 September 1960 2154 Underhill 24 September 1960 2155 Wodan 24 September 1960 2176 Donar 24 September 1960 2177 Oliver 24 September 1960 2200 Pasadena 24 September 1960 2210 Lois 24 September 1960 2224 Tucson 24 September 1960 2225 Serkowski 24 September 1960 2247 Hiroshima 24 September 1960 2256 Wiśniewski 24 September 1960 2289 McMillan 24 September 1960 2317 Galya 24 September 1960 2318 Lubarsky 24 September 1960 2319 Aristides 17 October 1960 2339 Anacreon 24 September 1960 2412 Wil 17 October 1960 2413 van de Hulst 24 September 1960 2435 Horemheb 24 September 1960 2436 Hatshepsut 24 September 1960 2462 Nehalennia 24 September 1960 2471 Ultrajectum 24 September 1960 2495 Noviomagum 17 October 1960 2662 Kandinsky 24 September 1960 2663 Miltiades 24 September 1960 2782 Leonidas 24 September 1960 2798 Vergilius 24 September 1960 2799 Justus 25 September 1960 2800 Ovidius 24 September 1960 2818 Juvenalis 24 September 1960 2823 van der Laan 24 September 1960 2876 Aeschylus 24 September 1960 2921 Sophocles 24 September 1960 2930 Euripides 24 September 1960 2934 Aristophanes 25 September 1960 2940 Bacon 24 September 1960 2986 Mrinalini 24 September 1960 2987 Sarabhai 24 September 1960 2992 Vondel 24 September 1960 3046 Molière 24 September 1960 3047 Goethe 24 September 1960 3079 Schiller 24 September 1960 3091 van den Heuvel 24 September 1960 3092 Herodotus 24 September 1960 3097 Tacitus 24 September 1960 3098 van Sprang 24 September 1960 3164 Prast 24 September 1960 3201 Sijthoff 24 September 1960 3218 Delphine 24 September 1960 3226 Plinius 24 September 1960 3244 Petronius 24 September 1960 3251 Eratosthenes 24 September 1960 3279 Solon 17 October 1960 3290 Azabu 19 September 1973 3292 Sather 24 September 1960 3293 Rontaylor 24 September 1960 3294 Carlvesely 24 September 1960 3377 Lodewijk 24 September 1960 3538 Nelsonia 24 September 1960 3548 Eurybates 19 September 1973 3604 Berkhuijsen 17 October 1960 3664 Anneres 24 September 1960 3734 Waland 17 October 1960 3798 de Jager 16 October 1977 3868 Mendoza 24 September 1960 3877 Braes 24 September 1960 3936 Elst 16 October 1977 4007 Euryalos 19 September 1973 4043 Perolof 17 October 1977 4044 Erikhøg 16 October 1977 4064 Marjorie 24 September 1960 4065 Meinel 24 September 1960 4068 Menestheus 19 September 1973 4108 Rakos 16 October 1977 4138 Kalchas 19 September 1973 4161 Amasis 24 September 1960 4180 Anaxagoras 24 September 1960 4230 van den Bergh 19 September 1973 4294 Horatius 24 September 1960 4295 Wisse 24 September 1960 4354 Euclides 24 September 1960 4355 Memphis 17 October 1960 4356 Marathon 17 October 1960 4357 Korinthos 29 September 1973 4385 Elsässer 24 September 1960 4386 Lüst 26 September 1960 4387 Tanaka 19 September 1973 4412 Chephren 26 September 1960 4413 Mycerinos 24 September 1960 4414 Sesostris 24 September 1960 4415 Echnaton 24 September 1960 4416 Ramses 24 September 1960 4548 Wielen 24 September 1960 4549 Burkhardt 29 September 1973 4586 Gunvor 24 September 1960 4587 Rees 30 September 1973 4646 Kwee 24 September 1960 4721 Atahualpa 29 September 1973 4722 Agelaos 16 October 1977 4752 Myron 29 September 1973 4753 Phidias 16 October 1977 4754 Panthoos 16 October 1977 4757 Liselotte 19 September 1973 4846 Tuthmosis 24 September 1960 4847 Amenhotep 24 September 1960 4848 Tutenchamun 30 September 1973 4876 Strabo 29 September 1973 4877 Humboldt 25 September 1973 4906 Seneferu 24 September 1960 4907 Zoser 17 October 1960 4960 Mayo 24 September 1960 4977 Rauthgundis 24 September 1960 4978 Seitz 29 September 1973 5009 Sethos 24 September 1960 5010 Amenemhêt 24 September 1960 5011 Ptah 24 September 1960 5012 Eurymedon 17 October 1960 5037 Habing 24 September 1960 5041 Theotes 19 September 1973 5071 Schoenmaker 30 September 1973 5148 Giordano 17 October 1960 5149 Leibniz 24 September 1960 5150 Fellini 17 October 1960 5151 Weerstra 29 September 1973 5194 Böttger 24 September 1960 5195 Kaendler 26 March 1971 5196 Bustelli 30 September 1973 5197 Rottmann 29 September 1973 5243 Clasien 29 September 1973 5244 Amphilochos 29 September 1973 5265 Schadow 24 September 1960 5266 Rauch 29 September 1973 5296 Friedrich 17 October 1960 5297 Schinkel 29 September 1973 5340 Burton 24 September 1960 5341 Purgathofer 24 September 1960 5342 Le Poole 30 September 1973 5383 Leavitt 29 September 1973 5408 Thé 25 March 1971 5450 Sokrates 24 September 1960 5451 Plato 24 September 1960 5490 Burbidge 24 September 1960 5491 Kaulbach 26 March 1971 5492 Thoma 26 March 1971 5493 Spitzweg 24 September 1973 5529 Perry 24 September 1960 5530 Eisinga 24 September 1960 5531 Carolientje 29 September 1973 5610 Balster 16 October 1977 5655 Barney 29 September 1973 5694 Berényi 24 September 1960 5695 Remillieux 24 September 1960 5696 Ibsen 24 September 1960 5697 Arrhenius 24 September 1960 5698 Nolde 26 March 1971 5699 Munch 16 October 1977 5700 Homerus 16 October 1977 5756 Wassenbergh 24 September 1960 5789 Sellin 24 September 1960 5790 Nagasaki 17 October 1960 5791 Comello 29 September 1973 5837 Hedin 24 September 1960 5838 Hamsun 29 September 1973 5884 Dolezal 24 September 1960 5885 Apeldoorn 30 September 1973 5928 Pindarus 19 September 1973 5981 Kresilas 24 September 1960 5982 Polykletus 13 May 1971