2741 Valdivia, provisional designation 1975 XG, is a background asteroid from the central regions of the asteroid belt, approximately 11 kilometers in diameter. It was discovered on 1 December 1975, by Chilean astronomers Carlos Torres and Sergio Barros at the Cerro El Roble Station northwest of Santiago de Chile. The asteroid was named after Spanish conquistador  Pedro de Valdivia.
Orbit and classification Valdivia is a non- family asteroid from the main belt's background population. It orbits the Sun in the central main-belt at a distance of 2.1–3.1 AU once every 4 years and 3 months (1,540 days). Its orbit has an eccentricity of 0.18 and an inclination of 10 ° with respect to the ecliptic.
The asteroid was first identified as
1935 CM at Uccle Observatory in February 1935, where the body's observation arc begins just a two weeks later, or more than 40 years before its official discovery observation at Cerro El Roble.
In August 2016, the so-far best-rated rotational
lightcurve of Valdivia was obtained by the Spanish amateur astronomer group OBAS. Lightcurve analysis gave a rotation period of 4.098 hours with a brightness variation of 0.25 magnitude ( ). U=3 Previously, in May 2003,  photometric observations made by Donald P. Pray at the Carbuncle Hill Observatory ( ) near Providence, Rhode Island, gave a synodic period of 4.096 hours and an amplitude of 0.40 in magnitude ( 912 ). U=2+
In addition astronomers at the
Palomar Transient Factory found a period of 4.096 hours with an amplitude of 0.28 om May 2011 ( ), U=2 and French amateur astronomer  René Roy obtained a period of 8.1922 hours (twice the period solution) with an amplitude of 0.36 ( ). U=2
In 2016, an international study modeled a lightcurve with a concurring period of 4.09668 hours and found two
spin axis of (269.0°, −31.0°) and (103.0°, −59.0°) in ecliptic coordinates (λ, β) ( ). U=n.a.
Diameter and albedo
According to the survey carried out by the
NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Valdivia measures between 9.13 and 11.679 kilometers in diameter and its surface has an albedo between 0.205 and 0.404,   while the Japanese  Akari satellite found an albedo of 0.244 and a diameter of 10.73 kilometers.
Collaborative Asteroid Lightcurve Link assumes an albedo of 0.10 – a compromise value between the carbonaceous (0.057) and stony (0.20) asteroids – and calculates a diameter of 17.52 kilometers based on an absolute magnitude of 11.9.
minor planet was named after Spanish conquistador Pedro de Valdivia (1502–1553), who conquered Chile with a small expedition corps after he served under Francisco Pizarro in Peru. Valdivia founded the cities Santiago (1541) and Concepción (1550) and became Chile's first royal governor. The city of  Valdivia in southern Chile is also named after him. The official naming citation was published by the Minor Planet Center on 26 March 1986 ( ). M.P.C. 10546
^ a b c d
"JPL Small-Body Database Browser: 2741 Valdivia (1975 XG)" (2016-11-23 last obs.). Jet Propulsion Laboratory . Retrieved . 18 September 2017
^ a b c
Schmadel, Lutz D. (2007). "(2741) Valdivia". Dictionary of Minor Planet Names – (2741) Valdivia. Springer Berlin Heidelberg. p. 224. doi: 10.1007/978-3-540-29925-7_2742. ISBN . 978-3-540-00238-3
^ a b c d e f
"LCDB Data for (2741) Valdivia". Asteroid Lightcurve Database (LCDB) . Retrieved . 18 September 2017
^ a b c d
Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters. 759 (1): 5. arXiv: . 1209.5794 Bibcode: 2012ApJ...759L...8M. doi: 10.1088/2041-8205/759/1/L8 . Retrieved . 18 September 2017
^ a b c d
Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode: 2011PASJ...63.1117U. doi: 10.1093/pasj/63.5.1117 . Retrieved . 17 October 2019 ( online, AcuA catalog p. 153)
^ a b c
Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv: . 1109.4096 Bibcode: 2011ApJ...741...68M. doi: 10.1088/0004-637X/741/2/68 . Retrieved . 18 September 2017
^ a b c d
Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv: . 1109.6407 Bibcode: 2011ApJ...741...90M. doi: 10.1088/0004-637X/741/2/90.
^ a b c
Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv: . 1504.04041 Bibcode: 2015AJ....150...75W. doi: 10.1088/0004-6256/150/3/75 . Retrieved . 18 September 2017
^ a b
Pray, Donald P. (March 2004). "Lightcurve analysis of asteroids 1225, 1301, 2134, 2741, and 3974". The Minor Planet Bulletin. 31 (1): 6–8. Bibcode: 2004MPBu...31....6P. ISSN 1052-8091 . Retrieved . 18 September 2017
^ a b
Hanus, J.; Durech, J.; Oszkiewicz, D. A.; Behrend, R.; Carry, B.; Delbo, M.; et al. (February 2016). "New and updated convex shape models of asteroids based on optical data from a large collaboration network". Astronomy and Astrophysics. 586: 24. arXiv: . 1510.07422 Bibcode: 2016A&A...586A.108H. doi: 10.1051/0004-6361/201527441.
^ a b
Brines, Pedro; Lozano, Juan; Rodrigo, Onofre; Fornas, A.; Herrero, David; Mas, Vicente; et al. (April 2017). "Sixteen Asteroids Lightcurves at Asteroids Observers (OBAS) - MPPD: 2016 June-November". The Minor Planet Bulletin. 44 (2): 145–149. Bibcode: 2017MPBu...44..145B. ISSN 1052-8091 . Retrieved . 18 September 2017
^ a b
Behrend, Raoul. "Asteroids and comets rotation curves – (2741) Valdivia". Geneva Observatory . Retrieved . 18 September 2017
^ a b
"2741 Valdivia (1975 XG)". Minor Planet Center . Retrieved . 18 September 2017
"MPC/MPO/MPS Archive". Minor Planet Center . Retrieved . 18 September 2017