| Birth date | November 22, 1973 (age 52) |
|---|---|
| Fields | Planetary astronomy |
| Education | Massachusetts Institute of Technology University of Hawaiʻi |
| Known for | Discovery of Eris, Sedna and other trans-Neptunian objects |
| Workplaces | 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. Trujillo, along with Michael Brown and David Rabinowitz, 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]
Career
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 Hawaiʻi 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.
Discoveries
| see § List of discovered minor planets |
As of February 2026, Trujillo is credited by the Minor Planet Center with the discovery and co-discovery of 88 numbered minor planets between 1996 and 2017, 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:
- Quaoar, co-discovered with Brown
- Sedna, co-discovered with Brown and Rabinowitz, possibly the first known inner Oort cloud object
- Orcus, co-discovered with Brown and Rabinowitz
- Eris, co-discovered with Brown and Rabinowitz – the only known TNO more massive than Pluto[3]
- , discovery also claimed by the Sierra Nevada Observatory, Spain (also see José Luis Ortiz Moreno).[7]
- , co-discovered with Brown and Rabinowitz in 2005, one of the first 5 official dwarf planets.[8]
List of discovered minor planets
As of February 2026 Minor Planet Center credits Chad Trujillo with the discovery and co-discovery of 88 minor planets during 1996–2017.[6]
| ' | October 9, 1996 | |
| ' | October 11, 1996 | |
| February 3, 1997 | ||
| ' | October 12, 1996 | |
| ' | October 8, 1996 | |
| ' | August 28, 1997 | |
| ' | April 28, 1998 | |
| ' | February 20, 1999 | |
| ' | February 6, 1997 | |
| 50000 Quaoar | June 4, 2002 |
| February 11, 1999 | ||
| March 3, 2000 | ||
| 65489 Ceto | March 22, 2003 | |
| 66652 Borasisi | September 8, 1999 | |
| 79360 Sila-Nunam | February 3, 1997 | |
| February 11, 1999 | ||
| February 15, 1999 | ||
| ' | February 20, 1999 | |
| ' | November 3, 2002 | |
| 90377 Sedna | November 14, 2003 |
| 90482 Orcus | February 17, 2004 | |
| September 8, 1999 | ||
| ' | October 8, 1996 | |
| ' | May 17, 2002 | |
| ' | July 26, 2003 | |
| ' | October 3, 2004 | |
| ' | December 18, 2001 | |
| ' | December 20, 2001 | |
| February 10, 1999 | ||
| September 7, 1999 |
| 136199 Eris | October 21, 2003 | |
| 136472 Makemake | March 31, 2005 | |
| September 7, 1999 | ||
| September 8, 1999 | ||
| September 8, 1999 | ||
| April 2, 2000 | ||
| ' | August 7, 2004 | |
| February 10, 1999 | ||
| February 11, 1999 | ||
| February 12, 1999 |
| ' | September 6, 1999 | |
| 208996 Achlys | January 13, 2003 | |
| May 19, 2002 | ||
| May 17, 2002 | ||
| 307261 Mani | June 18, 2002 | |
| 341520 Mors-Somnus | October 14, 2007 | |
| September 7, 1999 | ||
| 385571 Otrera | October 16, 2004 | |
| 385695 Clete | October 8, 2005 | |
| September 7, 1999 |
| ' | February 10, 1999 | |
| 471143 Dziewanna | March 13, 2010 | |
| May 7, 2002 | ||
| March 17, 2013 | ||
| March 28, 2014 | ||
| March 27, 2014 | ||
| April 28, 1998 | ||
| March 31, 2000 | ||
| August 26, 2002 | ||
| October 19, 2003 |
| ' | March 16, 2013 | |
| March 16, 2013 | ||
| March 24, 2014 | ||
| February 6, 1997 | ||
| September 6, 1999 | ||
| 532037 Chiminigagua | March 17, 2013 | |
| March 17, 2013 | ||
| March 17, 2015 | ||
| 541132 Leleakuhonua | October 13, 2015 | |
| April 13, 2015 |
| May 8, 2013 | ||
| October 12, 1996 | ||
| February 2, 1997 | ||
| April 28, 1998 | ||
| February 11, 1999 | ||
| February 11, 1999 | ||
| February 11, 1999 | ||
| February 12, 1999 | ||
| March 31, 2000 | ||
| ' | October 8, 2005 |
| December 11, 2012 | ||
| March 28, 2014 | ||
| ' | July 26, 2017 | |
| March 16, 2013 | ||
| March 16, 2013 | ||
| September 21, 2014 | ||
| June 27, 2009 | ||
| March 16, 2013 |
Satellites and uncredited discoveries
| Object | Discovery date | Type | Credit went to.. |
|---|---|---|---|
| Haumea | December 28, 2004 | DP | |
| 55565 Aya | January 10, 2002 | TNO | The Palomar Observatory team with Michael Brown |
| November 5, 2012 | TNO | no 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, 2005 | Satellite | Michael Brown and the adaptive-optics team[9] |
| (136199) Eris I Dysnomia | September 10, 2005 | Satellite | Michael 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]
References
- ^ Schmadel, Lutz D. (2007). "(12101) Trujillo". Dictionary of Minor Planet Names. Springer Berlin Heidelberg. p. 776. doi:10.1007/978-3-540-29925-7_8527. ISBN 978-3-540-00238-3.
- ^ "136199 Eris (2003 UB313)". Minor Planet Center. Retrieved July 26, 2016.
- ^ 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. S2CID 21468196. Retrieved July 26, 2016.
- ^ "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.
- ^ "Chad Trujillo CV"
- ^ "Minor Planet Discoverers (by number)". Minor Planet Center. February 25, 2026. Retrieved March 15, 2026.
- ^ "136108 Haumea (2003 EL61)". Minor Planet Center. Retrieved July 26, 2016.
- ^ "136472 Makemake (2005 FY9)". Minor Planet Center. Retrieved July 26, 2016.
- ^ "Dwarf Planets and their Systems". US Geological Survey Gazetteer of Planetary Nomenclature. Retrieved October 16, 2018.
- ^ 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. S2CID 119408563. Retrieved October 16, 2018.
- ^ "SCIENCE SPECTRUM MAGAZINE ANNOUNCES TOP MINORITIES IN SCIENCE". May 8, 2006. Retrieved April 4, 2018.