Chad Trujillo

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Chad Trujillo
Chad Trujillo.jpg
Chadwick A. Trujillo

(1973-11-22) November 22, 1973 (age 46)
Education Massachusetts Institute of Technology
University of Hawaii
Known forDiscovery of Eris, Sedna and other trans-Neptunian objects
Scientific career
Fields Planetary astronomy
Institutions Gemini Observatory
Northern Arizona University

Chadwick A. Trujillo (born November 22, 1973) is an American astronomer, discoverer of minor planets and the co-discoverer of Eris, the most massive dwarf planet known in the Solar System. [1] [2]


Trujillo works with computer software and has examined the orbits of the numerous trans-Neptunian objects (TNOs), which is the outer area of the Solar System that he specialized in. In late August 2005, it was announced that Trujillo, along with Michael Brown and David Rabinowitz, had discovered Eris in 2003. [2] As a result of the discovery of the satellite Dysnomia, Eris was the first TNO known to be more massive than Pluto. [3]


Trujillo attended Oak Park and River Forest High School in Oak Park, Illinois. He received his B.Sc. in physics from the Massachusetts Institute of Technology in 1995, and was a member of the Xi chapter of Tau Epsilon Phi, and received his Ph.D. in astronomy from the University of Hawaii in 2000.

Between 2000 and 2003 Trujillo was a postdoctoral scholar at Caltech. In 2003, he started working as an astronomer at the Gemini Observatory in Hawaii. [4]

In 2013 Trujillo became head of the Adaptive Optics/Telescope Department at the Gemini Observatory, and continued until 2016. As of 2016, Trujillo is assistant professor at the department of Astronomy and Planetary Science at Northern Arizona University. [5]

He studies the Kuiper belt and the outer Solar System.


Minor planets discovered: 62 [6]
see § List of discovered minor planets

Trujillo is credited by the Minor Planet Center with the discovery and co-discovery of 54 numbered minor planets between 1996 and 2013, including many trans-Neptunian objects (TNOs) from the Kuiper belt (see table). [6] The last major TNO, Eris, was at first considered by him, his team, NASA, and many others to be the tenth planet, [4] but the International Astronomical Union assigned it to the new classificatory category of dwarf planet.

The possible dwarf planets Trujillo discovered are:

List of discovered minor planets

The Minor Planet Center credits Chad Trujillo with the discovery and co-discovery of 57 minor planets during 1996–2013. [6] His numerous co-discoverers were: A D. C. Jewitt, B J. X. Luu, C J. Chen, D K. Berney, E D. J. Tholen, F M. E. Brown, G W. Evans, H S. S. Sheppard, J D. L. Rabinowitz, K A. Udalski, L M. Kubiak and M R. Poleski.

(15874) 1996 TL66 October 9, 1996 list [A] [B] [C]
(15875) 1996 TP66 October 11, 1996 list [B] [A]
(15883) 1997 CR29February 3, 1997 list [C] [A]
(19308) 1996 TO66 October 12, 1996 list [A] [B]
(20161) 1996 TR66 October 8, 1996 list [A] [B] [C]
(24952) 1997 QJ4 August 28, 1997 list [B] [A] [D]
(24978) 1998 HJ151 April 28, 1998 list [B] [E] [A]
(26375) 1999 DE9 February 20, 1999 list [B]
(33001) 1997 CU29 February 6, 1997 list [A] [B] [C]
50000 Quaoar June 4, 2002 list [F]
(59358) 1999 CL158February 11, 1999 list [B] [A]
(60608) 2000 EE173March 3, 2000 list [B] [G]
65489 Ceto March 22, 2003 list [F]
66652 Borasisi September 8, 1999 list [B] [A]
79360 Sila-Nunam February 3, 1997 list [B] [A] [C]
(79969) 1999 CP133February 11, 1999 list [B] [A]
(79978) 1999 CC158February 15, 1999 list [A] [B] [H]
(79983) 1999 DF9 February 20, 1999 list [B] [A]
(84719) 2002 VR128 November 3, 2002 list [F]
90377 Sedna November 14, 2003 list [F] [J]
90482 Orcus February 17, 2004 list [F] [J]
(91554) 1999 RZ215September 8, 1999 list [B] [A]
(118228) 1996 TQ66 October 8, 1996 list [C] [A] [B]
(119951) 2002 KX14 May 17, 2002 list [F]
(120178) 2003 OP32 July 26, 2003 list [F] [J]
(120348) 2004 TY364 October 3, 2004 list [F] [J]
(126154) 2001 YH140 December 18, 2001 list [F]
(126155) 2001 YJ140 December 20, 2001 list [F]
(129746) 1999 CE119February 10, 1999 list [B] [A]
(134568) 1999 RH215September 7, 1999 list [A] [B]
136199 Eris October 21, 2003 list [F] [J]
136472 Makemake March 31, 2005 list [F] [J]
(137294) 1999 RE215September 7, 1999 list [B] [A]
(137295) 1999 RB216September 8, 1999 list [A] [B]
(148112) 1999 RA216September 8, 1999 list [A] [B]
(168700) 2000 GE147April 2, 2000 list [A] [H]
(175113) 2004 PF115 August 7, 2004 list [F] [J]
(181867) 1999 CV118February 10, 1999 list [A] [B]
(181868) 1999 CG119February 11, 1999 list [B] [A]
(181871) 1999 CO153February 12, 1999 list [B] [A]
(181902) 1999 RD215 September 6, 1999 list [B] [A]
(208996) 2003 AZ84 January 13, 2003 list [F]
(250112) 2002 KY14May 19, 2002 list [F]
(307251) 2002 KW14May 17, 2002 list [F]
(307261) 2002 MS4 June 18, 2002 list [F]
341520 Mors-Somnus October 14, 2007 list [H]
(385201) 1999 RN215September 7, 1999 list [A] [B]
385571 Otrera October 16, 2004 list [H]
385695 Clete October 8, 2005 list [H]
(415720) 1999 RU215September 7, 1999 list [B] [A]
(469306) 1999 CD158 February 10, 1999 list [B] [A]
471143 Dziewanna March 13, 2010 list [K] [L]
(471165) 2010 HE79April 21, 2010 list [H] [M] [K]
(471921) 2013 FC28March 17, 2013 list [H]
(503858) 1998 HQ151April 28, 1998 list [E] [A] [B]
(508792) 2000 FX53March 31, 2000 list [H] [A]
(523597) 2002 QX47August 26, 2002 list [F]
(523899) 1997 CV296 February 1997 list [C] [A] [B]
(523983) 1999 RY2146 September 1999 list [A] [B]
(532037) 2013 FY2717 March 2013 list [H]
(532038) 2013 FB2817 March 2013 list [H]
541132 Leleākūhonua 13 October 2015 list [E] [H]

Satellites and uncredited discoveries

ObjectDiscovery dateTypeCredit went to..
Haumea December 28, 2004 DP José Luis Ortiz Moreno et al.
(55565) 2002 AW197 January 10, 2002 TNO The Palomar Observatory team with Michael Brown
2012 VP113 November 5, 2012TNOno official discoverers for unnumbered objects; candidate: S. S. Sheppard
(136108) Haumea I Hiʻiaka January 26, 2005 Satellite Michael Brown and the adaptive-optics team, [9] D. L. Rabinowitz [10]
(136108) Haumea II Namaka July 30, 2005SatelliteMichael Brown and the adaptive-optics team [9]
(136199) Eris I Dysnomia September 10, 2005SatelliteMichael Brown and the adaptive-optics team: M. A. van Dam, A. H. Bouchez, D. Le Mignant, R. D. Campbell, J. C. Y. Chin, A. Conrad, S. K. Hartman, E. M. Johansson, R. E. Lafon, D. L. Rabinowitz, P. J. Stomski Jr., D. M. Summers, and P. L. Wizinowich

Honors and awards

The main-belt asteroid 12101 Trujillo is named for him. [1]

In 2006 he was named one of the Science Spectrum Magazine Trailblazer, top minority in science. [11]

Related Research Articles

Trans-Neptunian object any object in the Solar System that orbits the Sun at a greater average distance than Neptune

A trans-Neptunian object (TNO), also written transneptunian object, is any minor planet or dwarf planet in the Solar System that orbits the Sun at a greater average distance than Neptune, which has a semi-major axis of 30.1 astronomical units (AU).

90482 Orcus Trans-Neptunian object and possible dwarf planet

90482 Orcus, provisional designation 2004 DW, is a trans-Neptunian object with a large moon, Vanth. With a diameter of 910 km (570 mi), it is a possible dwarf planet. The surface of Orcus is relatively bright with albedo reaching 23 percent, neutral in color and rich in water ice. The ice is predominantly in crystalline form, which may be related to past cryovolcanic activity. Other compounds like methane or ammonia may also be present on its surface. It was discovered by American astronomers Michael Brown, Chad Trujillo, and David Rabinowitz on 17 February 2004.

Michael E. Brown American astronomer

Michael E. Brown is an American astronomer, who has been professor of planetary astronomy at the California Institute of Technology (Caltech) since 2003. His team has discovered many trans-Neptunian objects (TNOs), including the dwarf planet Eris, which was originally thought to be bigger than Pluto, triggering a debate on the definition of a planet.

David L. Rabinowitz American astronomer

David Lincoln Rabinowitz is an American astronomer, discoverer of minor planets and researcher at Yale University.

Haumea Dwarf planet in the Solar System

Haumea is a likely dwarf planet located beyond Neptune's orbit. It was discovered in 2004 by a team headed by Mike Brown of Caltech at the Palomar Observatory in the United States and independently in 2005 by a team headed by José Luis Ortiz Moreno at the Sierra Nevada Observatory in Spain, though the latter claim has been contested. On September 17, 2008, it was named after Haumea, the Hawaiian goddess of childbirth, under the expectation by the International Astronomical Union (IAU) that it would prove to be a dwarf planet. It is probably the third-largest known trans-Neptunian object, after Eris and Pluto.

Makemake Dwarf planet in the Solar System

Makemake is a likely dwarf planet and perhaps the second largest Kuiper belt object in the classical population, with a diameter approximately two-thirds that of Pluto. Makemake has one known satellite. Its extremely low average temperature, about 40 K (−230 °C), means its surface is covered with methane, ethane, and possibly nitrogen ices.

<span class="nowrap">(55565) 2002 AW<sub>197</sub></span>

(55565) 2002 AW197 is a classical, non-resonant trans-Neptunian object from the Kuiper belt in the outermost region of the Solar System, also known as cubewano. With a diameter of at least 700 kilometers (430 miles), Brown considers it a highly likely dwarf planet candidate. Tancredi notes that photometric observations suggest that it is a spheroid with a high albedo and small albedo spots. However, its low albedo suggests it does not have planetary geology. It is approximately tied (to within measurement uncertainties) as the largest unnamed object in the Solar System and the largest planetoid without a moon. It was discovered at Palomar Observatory in 2002 and has a rotation period of 8.8 hours and a moderately red color.

Dysnomia (moon)

Dysnomia (formally (136199) Eris I Dysnomia) is the only known moon of the dwarf planet Eris and likely the second-largest known moon of a dwarf planet, after Pluto I Charon. It was discovered in 2005 by Mike Brown and the laser guide star adaptive optics team at the W. M. Keck Observatory, and carried the provisional designation of S/2005 (2003 UB313) 1 until officially named Dysnomia (from the Ancient Greek word Δυσνομία meaning anarchy/lawlessness) after the daughter of the Greek goddess Eris.

Eris (dwarf planet) Dwarf planet beyond Pluto in the Solar System

Eris is the most massive and second-largest known dwarf planet in the Solar System. Eris was discovered in January 2005 by a Palomar Observatory-based team led by Mike Brown, and its discovery was verified later that year. In September 2006 it was named after the Greco-Roman goddess of strife and discord. Eris is the ninth-most massive known object directly orbiting the Sun, and the sixteenth-most massive overall in the Solar System. It is also the largest object that has not been visited by a spacecraft. Eris has been measured at 2,326 ± 12 kilometers (1,445 ± 7 mi) in diameter. Its mass is 0.27 percent that of the Earth and 127 percent that of dwarf planet Pluto, though Pluto is slightly larger by volume.

(24835) 1995 SM55, provisional designation 1995 SM55, is a trans-Neptunian object and member of the Haumea family that resides in the Kuiper belt, located in the outermost region of the Solar System. It was discovered on 19 September 1995, by American astronomer Nichole Danzl of the Spacewatch program at Kitt Peak National Observatory near Tucson, Arizona, in the United States. It measures approximately 600–700 kilometers in diameter and was the second-brightest known object in the Kuiper belt, after Pluto, until 1996 TO66 was discovered.

<span class="nowrap">(120178) 2003 OP<sub>32</sub></span>

(120178) 2003 OP32, also written as (120178) 2003 OP32, is a trans-Neptunian object (TNO) that resides in the Kuiper belt. It was discovered on July 26, 2003 by Michael E. Brown, Chad Trujillo and David L. Rabinowitz at Palomar Mountain in California.

(120348) 2004 TY364, provisionally known as 2004 TY364, is a trans-Neptunian object. It is an inner classical Kuiper belt object in the definition by Gladman, Marsden, and Van Laerhoven (e<0.24). Its inclination of almost 25 degrees disqualifies it as such in Marc Buie's definition. It is also not listed as a scattered disc object by the Minor Planet Center. It was discovered by Michael E. Brown, Chad Trujillo and David L. Rabinowitz on October 3, 2004 at the Palomar Observatory.

Moons of Haumea Natural satellites orbiting dwarf planet Haumea

The outer Solar System planetoid Haumea has two known moons, Hiʻiaka and Namaka, named after Hawaiian goddesses. These small moons were discovered in 2005, from observations of Haumea made at the large telescopes of the W. M. Keck Observatory in Hawaii.

Haumea was the first of the IAU-recognized dwarf planets to be discovered since Pluto in 1930. Its naming as a dwarf planet was delayed by several years due to controversy over who should receive credit for its discovery. A California Institute of Technology (Caltech) team headed by Michael E. Brown first noticed the object, but a Spanish team headed by José Luis Ortiz Moreno were the first to announce it, and so normally would receive credit. Brown accused the Spanish team of fraud, using Caltech observations without credit to make their discovery, while the Ortiz team accused the American team of political interference with the International Astronomical Union (IAU). The IAU officially recognized the Californian team's proposed name Haumea over the name proposed by the Spanish team, Ataecina, in September 2008.

225088 Gonggong Possible dwarf planet in the scattered-disc

225088 Gonggong (provisional designation: 2007 OR10) is a likely dwarf planet of the Solar System, and a member of the scattered disc beyond Neptune. It has a highly eccentric and inclined orbit during which it ranges from 34–101 astronomical units (5.1–15.1 billion kilometers; 3.2–9.4 billion miles) from the Sun. As of 2019, its distance from the Sun is 88 AU (13.2×10^9 km; 8.2×10^9 mi), and it is the sixth-farthest known Solar System object. Gonggong is in a 3:10 orbital resonance with Neptune, in which it completes three orbits around the Sun for every ten orbits completed by Neptune. Gonggong was discovered in July 2007 by American astronomers Megan Schwamb, Michael Brown, and David Rabinowitz at the Palomar Observatory, and the discovery was announced in January 2009.

50000 Quaoar Cold classical Kuiper belt object

50000 Quaoar is a non-resonant trans-Neptunian object (cubewano) and a possible dwarf planet in the Kuiper belt, a region of icy planetesimals beyond Neptune. It measures approximately 1,121 km (697 mi) in diameter, about half the diameter of Pluto. The object was discovered by American astronomers Chad Trujillo and Michael Brown at the Palomar Observatory on 4 June 2002. Signs of water ice on the surface of Quaoar have been found, which suggests that cryovolcanism may be occurring on Quaoar. A small amount of methane is present on its surface, which can only be retained by the largest Kuiper belt objects. In February 2007, Weywot, a synchronous moon in orbit around Quaoar, was discovered by Brown. Weywot is measured to be 170 km (110 mi) across. Both objects were named after mythological figures from the Native American Tongva people in Southern California. Quaoar is the Tongva creator deity and Weywot is his son.

The region of the Solar System beyond Neptune contains sparse populations of relatively small rocky and icy objects. These include the Kuiper belt, a group which includes the dwarf planet Pluto and other large planetoids such as Haumea and Makemake. Further out is the scattered disk, a group which includes Eris, a dwarf planet slightly smaller than Pluto, and even more distant detached objects such as Sedna.

<span class="nowrap">(386723) 2009 YE<sub>7</sub></span>

(386723) 2009 YE7, provisional designation 2009 YE7, is a trans-Neptunian object (TNO) discovered by David Rabinowitz on December 17, 2009 at the La Silla Observatory in Chile.


  1. 1 2 Schmadel, Lutz D. (2007). "(12101) Trujillo". Dictionary of Minor Planet Names – (12101) Trujillo. Springer Berlin Heidelberg. p. 776. doi:10.1007/978-3-540-29925-7_8527. ISBN   978-3-540-00238-3.
  2. 1 2 "136199 Eris (2003 UB313)". Minor Planet Center. Retrieved July 26, 2016.
  3. 1 2 Brown, Michael E.; Schaller, Emily L. (June 2007). "The Mass of Dwarf Planet Eris". Science. 316 (5831): 1585. Bibcode:2007Sci...316.1585B. doi:10.1126/science.1139415. PMID   17569855 . Retrieved July 26, 2016.
  4. 1 2 "UH Alumnus Chad Trujillo Helps in Discovery of 10th Planet". Nupepa. August 2005. Archived from the original on August 13, 2009. Retrieved July 26, 2016.
  5. "Chad Trujillo CV".
  6. 1 2 3 "Minor Planet Discoverers (by number)". Minor Planet Center. September 25, 2018. Retrieved October 16, 2018.
  7. "136108 Haumea (2003 EL61)". Minor Planet Center. Retrieved July 26, 2016.
  8. "136472 Makemake (2005 FY9)". Minor Planet Center. Retrieved July 26, 2016.
  9. 1 2 "Dwarf Planets and their Systems". US Geological Survey Gazetteer of Planetary Nomenclature. Retrieved October 16, 2018.
  10. Brown, M. E.; Bouchez, A. H.; Rabinowitz, D.; Sari, R.; Trujillo, C. A.; van Dam, M.; et al. (October 2005). "Keck Observatory Laser Guide Star Adaptive Optics Discovery and Characterization of a Satellite to the Large Kuiper Belt Object 2003 EL61". The Astrophysical Journal. 632 (1): L45–L48. Bibcode:2005ApJ...632L..45B. doi:10.1086/497641 . Retrieved October 16, 2018.