1529 Oterma

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1529 Oterma
Discovery [1]
Discovered byY. Väisälä
Discovery siteTurku Obs.
Discovery date26 January 1938
MPC designation(1529) Oterma
Named after
Liisi Oterma
1938 BC · 1950 PV
1959 RD1 · A912 VO
main-belt · Hilda[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc66.76 yr (24,385 days)
Aphelion4.7933 AU
Perihelion3.1916 AU
3.9924 AU
7.98 yr (2,914 days)
0° 7m 24.96s / day
Jupiter MOID0.8116 AU
Physical characteristics
Dimensions54.40 km (calculated)[3]
60.16±1.11 km[5]
15.75 h[6]
0.057 (assumed)[3]
Tholen = P [1] · P[3]
B–V = 0.764[1]
U–B = 0.386[1]
10.05[1][3][5] · 10.11±0.26[7]

1529 Oterma, provisional designation 1938 BC, is a reddish, rare-type Hildian asteroid from the outermost region of the asteroid belt, approximately 56 kilometers in diameter. It was discovered on 26 January 1938, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland.[8] It is named for Liisi Oterma.[2]

Orbit and classification[edit]

Orbit of 1529 Oterma

Oterma is a member of the Hilda family, a large group of asteroids that orbit in resonance with the gas giant Jupiter. Hildian asteroids are thought to have originated from the Kuiper belt in the outer Solar System.

It orbits the Sun in the outer main-belt at a distance of 3.2–4.8 AU once every 7 years and 12 months (2,914 days). Its orbit has an eccentricity of 0.20 and an inclination of 9° with respect to the ecliptic.[1]

It was first identified as A912 VO at Winchester Observatory in 1912 (799). The body's observation arc begins at Turku a few weeks after its official discovery observation.[8]

Physical characteristics[edit]

Oterma belongs to an exclusive group of 33 known asteroids with a spectral P-type in the Tholen classification scheme.[9]


During a study of 47 Hilda asteroids in the 1990s, a rotational lightcurve of Oterma was obtained from photometric observations at the Swedish Uppsala Astronomical Observatory and other places. It gave a rotation period of 15.75 hours with a change in brightness of 0.18 magnitude (U=2).[6]

Diameter and albedo[edit]

According to the space-based surveys carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission and by the Japanese Akari satellite, Oterma measures 56.33 and 60.1 kilometers in diameter and its surface has an albedo of 0.054 and 0.047, respectively.[4][5] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for carbonaceous asteroids of 0.057 and calculates a diameter of 54.40 kilometers, with an absolute magnitude of 10.05.[3]


Oterma was named for Liisi Oterma (1915–2001), first Finnish female astronomer with a Ph.D. and a discoverer of minor planets and comets at the Turku observatory between 1939 and 1953.[2] The approved naming citation was published by the Minor Planet Center before November 1977 (M.P.C. 3929).[10]


  1. ^ a b c d e f g "JPL Small-Body Database Browser: 1529 Oterma (1938 BC)" (2017-03-29 last obs.). Jet Propulsion Laboratory. Retrieved 30 June 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (1529) Oterma. Springer Berlin Heidelberg. p. 121. ISBN 978-3-540-00238-3. Retrieved 31 December 2016.
  3. ^ a b c d e f "LCDB Data for (1529) Oterma". Asteroid Lightcurve Database (LCDB). Retrieved 31 December 2016.
  4. ^ a b c Grav, T.; Mainzer, A. K.; Bauer, J.; Masiero, J.; Spahr, T.; McMillan, R. S.; et al. (January 2012). "WISE/NEOWISE Observations of the Hilda Population: Preliminary Results". The Astrophysical Journal. 744 (2): 15. arXiv:1110.0283. Bibcode:2012ApJ...744..197G. doi:10.1088/0004-637X/744/2/197. Retrieved 31 December 2016.
  5. ^ 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 31 December 2016.
  6. ^ a b Dahlgren, M.; Lahulla, J. F.; Lagerkvist, C.-I.; Lagerros, J.; Mottola, S.; Erikson, A.; et al. (June 1998). "A Study of Hilda Asteroids. V. Lightcurves of 47 Hilda Asteroids". Icarus. 133 (2): 247–285. Bibcode:1998Icar..133..247D. doi:10.1006/icar.1998.5919. Retrieved 16 August 2016.
  7. ^ Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 31 December 2016.
  8. ^ a b "1529 Oterma (1938 BC)". Minor Planet Center. Retrieved 31 December 2016.
  9. ^ "JPL Small-Body Database – Query spectral type P (Tholen)". JPL Solar System Dynamics. Retrieved 16 August 2016.
  10. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 31 December 2016.

External links[edit]