15224 Penttilä

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15224 Penttilä
Discovery [1]
Discovered by E. Bowell
Discovery site Anderson Mesa Stn.
Discovery date 15 May 1985
MPC designation (15224) Penttilä
Named after
Antti Penttilä [2]
(Finnish astronomer)
1985 JG · 1970 HB
2000 HR19
main-belt · (inner)[3]
Orbital characteristics[1]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc 45.30 yr (16,545 days)  
Aphelion 3.0004 AU
Perihelion 1.8329 AU
2.4167 AU
Eccentricity 0.2416
3.76 yr (1,372 days)
0° 15m 44.28s / day
Inclination 12.347°
Physical characteristics
Dimensions 4.93 km (calculated)[3]
7.924±0.119 km[4]
8.79±3.79 km[5]
4.0097±0.0064 h (S)[6]
4.377±0.001 h[7]
4.3771±0.0005 h (R)[6]
0.20 (assumed)[3]
13.988±0.006 (R)[6]
14.309±0.009 (S)[6]

15224 Penttilä, provisional designation 1985 JG, is a stony background asteroid from the inner regions of the asteroid belt, approximately 7 kilometers in diameter. It was discovered on 15 May 1985, by American astronomer Edward Bowell at Lowell's Anderson Mesa Station, Arizona.[2]

Orbit and classification[edit]

Penttilä orbits the Sun at a distance of 1.8–3.0 AU once every 3 years and 9 months (1,372 days). Its orbit has an eccentricity of 0.24 and an inclination of 12° with respect to the ecliptic.[1] Due to precovery images taken at the Crimean Astrophysical Observatory in 1970, the asteroid's observation arc spans over a period of almost half a century.[2]

Physical characteristics[edit]

Penttilä is an assumed S-type asteroid.[3]

In June 2015, a rotational light-curve was obtained for this asteroid from photometric observations by astronomer Daniel Klinglesmith at Etscorn Campus Observatory (719), New Mexico . It gave it a rotation period of 4.377±0.001 hours with a brightness amplitude of 0.55 in magnitude (U=3-).[7] Previously, in August 2012, a nearly identical photometric result in the R-band was obtained at the U.S. Palomar Transient Factory, California. The light-curve gave a period of 4.3771±0.0064 hours with a magnitude variation of 0.46 (U=2).[6]

According to the surveys carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, the asteroid measures 7.9 and 8.8 kilometers in diameter, with a low albedo of 0.085 and 0.069, respectively.[4][5] However, the Collaborative Asteroid Lightcurve Link assumes a standard albedo for stony asteroids of 0.20, and hence calculates a smaller diameter of 4.9 kilometers.[3]


The minor planet was named for Finnish postdoctoral researcher Antti Penttilä (born 1977) at the University of Helsinki, and an expert on light reflection and absorption on the surface of small Solar System bodies such as asteroids and cometary nuclei, as well as of the cosmic dust released by cometary comae.[2] Naming citation was published on 12 July 2014 (M.P.C. 89081).[8]


  1. ^ a b c d "JPL Small-Body Database Browser: 15224 Penttila (1985 JG)" (2015-08-14 last obs.). Jet Propulsion Laboratory. Retrieved 23 August 2016. 
  2. ^ a b c d "15224 Penttila (1985 JG)". Minor Planet Center. Retrieved 23 August 2016. 
  3. ^ a b c d e f g "LCDB Data for (15224) Penttila". Asteroid Lightcurve Database (LCDB). Retrieved 23 August 2016. 
  4. ^ 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:1109.6407Freely accessible. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. Retrieved 23 August 2016. 
  5. ^ 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:1209.5794Freely accessible. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. Retrieved 23 August 2016. 
  6. ^ a b c d e 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:1504.04041Freely accessible. Bibcode:2015AJ....150...75W. doi:10.1088/0004-6256/150/3/75. Retrieved 23 August 2016. 
  7. ^ a b Klinglesmith, Daniel A., III; Hanowell, Jesse; Hendrickx, Sebastian; Madden, Karl; Montgomery, Samuel (October 2015). "Asteroids Observed at Etscorn Observatory: 2015 April - June". The Minor Planet Bulletin. 42 (4): 251–252. Bibcode:2015MPBu...42..251K. ISSN 1052-8091. Retrieved 23 August 2016. 
  8. ^ "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 23 August 2016. 

External links[edit]