# Chad Trujillo

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.
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. As a result of the discovery of the satellite Dysnomia, Eris was the first TNO known to be more massive than Pluto.

## 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.
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.
He studies the Kuiper belt and the outer Solar System.

## Discoveries

Minor planets discovered: 62 :
* 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). The last major TNO, Eris, was at first considered by him, his team, NASA, and many others to be the tenth planet, 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
* Haumea, discovery also claimed by the Sierra Nevada Observatory, Spain (also see José Luis Ortiz Moreno).
* Makemake, co-discovered with Brown and Rabinowitz in 2005, one of the first 5 official dwarf planets.

### 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. 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, $^M$ R. Poleski and $^N$ Glenn Smith.
| (15874) 1996 TL66 | October 9, 1996 | list |
| (15875) 1996 TP66 | October 11, 1996 | list |
| (15883) 1997 CR$_{29}$ | February 3, 1997 | list |
| (19308) 1996 TO66 | October 12, 1996 | list |
| (20161) 1996 TR66 | October 8, 1996 | list |
| (24952) 1997 QJ4 | August 28, 1997 | list |
| (24978) 1998 HJ151 | April 28, 1998 | list |
| (26375) 1999 DE9 | February 20, 1999 | list |
| (33001) 1997 CU29 | February 6, 1997 | list |
| 50000 Quaoar | June 4, 2002 | list |
| (59358) 1999 CL$_{158}$ | February 11, 1999 | list |
| (60608) 2000 EE$_{173}$ | March 3, 2000 | list |
| 65489 Ceto | March 22, 2003 | list |
| 66652 Borasisi | September 8, 1999 | list |
| 79360 Sila-Nunam | February 3, 1997 | list |
| (79969) 1999 CP$_{133}$ | February 11, 1999 | list |
| (79978) 1999 CC$_{158}$ | February 15, 1999 | list |
| (79983) 1999 DF9 | February 20, 1999 | list |
| (84719) 2002 VR128 | November 3, 2002 | list |
| 90377 Sedna | November 14, 2003 | list |
| 90482 Orcus | February 17, 2004 | list |
| (91554) 1999 RZ$_{215}$ | September 8, 1999 | list |
| (118228) 1996 TQ66 | October 8, 1996 | list |
| (119951) 2002 KX14 | May 17, 2002 | list |
| (120178) 2003 OP32 | July 26, 2003 | list |
| (120348) 2004 TY364 | October 3, 2004 | list |
| (126154) 2001 YH140 | December 18, 2001 | list |
| (126155) 2001 YJ140 | December 20, 2001 | list |
| (129746) 1999 CE$_{119}$ | February 10, 1999 | list |
| (134568) 1999 RH$_{215}$ | September 7, 1999 | list |
| 136199 Eris | October 21, 2003 | list |
| 136472 Makemake | March 31, 2005 | list |
| (137294) 1999 RE$_{215}$ | September 7, 1999 | list |
| (137295) 1999 RB$_{216}$ | September 8, 1999 | list |
| (148112) 1999 RA$_{216}$ | September 8, 1999 | list |
| (168700) 2000 GE$_{147}$ | April 2, 2000 | list |
| (175113) 2004 PF115 | August 7, 2004 | list |
| (181867) 1999 CV$_{118}$ | February 10, 1999 | list |
| (181868) 1999 CG$_{119}$ | February 11, 1999 | list |
| (181871) 1999 CO$_{153}$ | February 12, 1999 | list |
| (181902) 1999 RD215 | September 6, 1999 | list |
| (208996) 2003 AZ84 | January 13, 2003 | list |
| (250112) 2002 KY$_{14}$ | May 19, 2002 | list |
| (307251) 2002 KW$_{14}$ | May 17, 2002 | list |
| (307261) 2002 MS4 | June 18, 2002 | list |
| 341520 Mors-Somnus | October 14, 2007 | list |
| (385201) 1999 RN$_{215}$ | September 7, 1999 | list |
| 385571 Otrera | October 16, 2004 | list |
| 385695 Clete | October 8, 2005 | list |
| (415720) 1999 RU$_{215}$ | September 7, 1999 | list |
| (469306) 1999 CD158 | February 10, 1999 | list |
| 471143 Dziewanna | March 13, 2010 | list |
| (471165) 2010 HE$_{79}$ | April 21, 2010 | list |
| (471921) 2013 FC$_{28}$ | March 17, 2013 | list |
| (503858) 1998 HQ$_{151}$ | April 28, 1998 | list |
| (508792) 2000 FX$_{53}$ | March 31, 2000 | list |
| (523597) 2002 QX$_{47}$ | August 26, 2002 | list |
| (523899) 1997 CV$_{29}$ | February 6, 1997 | list |
| (523983) 1999 RY$_{214}$ | September 6, 1999 | list |
| (532037) 2013 FY$_{27}$ | March 17, 2013 | list |
| (532038) 2013 FB$_{28}$ | March 17, 2013 | list |
| 541132 Leleākūhonua | October 13, 2015 | list |

### Satellites and uncredited discoveries

| Object | Discovery date | Type | Credit went to.. |
| Haumea | December 28, 2004 | DP | |
| (55565) 2002 AW197 | January 10, 2002 | TNO | The Palomar Observatory team with Michael Brown |
| 2012 VP113 | 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, D. L. Rabinowitz |
| (136108) Haumea II Namaka | July 30, 2005 | Satellite | Michael Brown and the adaptive-optics team |
| (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.
In 2006 he was named one of the Science Spectrum Magazine Trailblazer, top minority in science.