2181 Fogelin, provisional designation 1942 YA, is a Eunomian asteroid from the central regions of the asteroid belt, approximately 11 kilometers (7 miles) in diameter. It was discovered on 28 December 1942, by Germany astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany. In 1980, it was named for Eric S. Fogelin an assistant at the  Minor Planet Center. The likely elongated  S-type asteroid has a rotation period of 14.07 hours.
Orbit and classification Fogelin is a member of the Eunomia family ( ), 502  a prominent  family of stony asteroid and the largest one in the intermediate main belt with more than 5,000 known members. It orbits the Sun in the  central main-belt at a distance of 2.3–2.9 AU once every 4 years and 2 months (1,523 days; semi-major axis of 2.59 AU). Its orbit has an eccentricity of 0.12 and an inclination of 13 ° with respect to the ecliptic.
observation arc begins at Heidelberg with its official discovery observation in December 1942.
Fogelin is an assumed S-type asteroid, in line with the overall  spectral type seen among Eunomian asteroids.  : Near-IR spectroscopy at the 23 NASA Infrared Telescope Facility with the SpeX instrument showed that the asteroid contains mafic minerals, which are rich in magnesium and iron.
In March 2010, a rotational
lightcurve of Fogelin was obtained from photometric observations by Richard Durkee at the Shed of Science Observatory ( ) in the United States. Lightcurve analysis gave a well-defined H39 rotation period of 14.07 hours with a brightness amplitude of 0.57 magnitude, indicative of an elongated shape ( ). U=3
Diameter and albedo
According to the surveys carried out by the Japanese
Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Fogelin measures between 10.067 and 11.29 kilometers in diameter and its surface has an albedo between 0.200 and 0.252.  
Collaborative Asteroid Lightcurve Link assumes an albedo of 0.21 – derived from 15 Eunomia, the family's parent body and namesake – and calculates a diameter of 11.55 kilometers based on an absolute magnitude of 12.0.
minor planet was named by Brian Marsden and Conrad Bardwell of the Minor Planet Center, after their assistant, Eric S. Fogelin. During 1979–1980, he was preparing the center's computerized data and helped publishing the Minor Planet Circulars. The official naming citation was published by the Minor Planet Center on 1 August 1980 (  ). M.P.C. 5451
^ a b c d e f g
"2181 Fogelin (1942 YA)". Minor Planet Center . Retrieved . 19 March 2018
^ a b c d
"JPL Small-Body Database Browser: 2181 Fogelin (1942 YA)" (2018-01-25 last obs.). Jet Propulsion Laboratory . Retrieved . 19 March 2018
^ a b c d e f g h i
"LCDB Data for (2181) Fogelin". Asteroid Lightcurve Database (LCDB) . Retrieved . 19 March 2018
^ a b
"Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0 . Retrieved . 19 March 2018
^ a b c
Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos" (PDF). The Astrophysical Journal. 791 (2): 11. arXiv: . 1406.6645 Bibcode: 2014ApJ...791..121M. doi: 10.1088/0004-637X/791/2/121 . Retrieved . 19 March 2018
^ 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" (PDF). The Astrophysical Journal. 741 (2): 25. arXiv: . 1109.6407 Bibcode: 2011ApJ...741...90M. doi: 10.1088/0004-637X/741/2/90 . Retrieved . 19 March 2018
^ 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 . 19 March 2018 Online catalog
^ a b
Durkee, Russell I. (July 2010). "Asteroids Observed from the Shed of Science Observatory: 2009 October - 2010 March". The Minor Planet Bulletin. 37 (3): 125–127. Bibcode: 2010MPBu...37..125D. ISSN 1052-8091 . Retrieved . 19 March 2018
^ a b
Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). "Identification and Dynamical Properties of Asteroid Families" (PDF). Asteroids IV: 297–321. arXiv: . 1502.01628 Bibcode: 2015aste.book..297N. doi: 10.2458/azu_uapress_9780816532131-ch016 . Retrieved . 19 March 2018
Birlan, Mirel; Barucci, Maria Antonietta; Vernazza, Pierre; Fulchignoni, Marcello; Binzel, Richard P.; Bus, Schelte J.; et al. (June 2004). "Near-IR spectroscopy of asteroids 21 Lutetia, 89 Julia, 140 Siwa, 2181 Fogelin and 5480 (1989YK8), potential targets for the Rosetta mission; remote observations campaign on IRTF" (PDF). New Astronomy. 9 (5): 343–351. arXiv: . astro-ph/0312638 Bibcode: 2004NewA....9..343B. doi: 10.1016/j.newast.2003.12.005 . Retrieved . 19 March 2018
"MPC/MPO/MPS Archive". Minor Planet Center . Retrieved . 19 March 2018