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1021 Flammario

1021 Flammario
Discovery [1]
Discovered byM. F. Wolf
Discovery siteHeidelberg Obs.
Discovery date11 March 1924
MPC designation(1021) Flammario
Named after
Camille Flammarion[2]
(French astronomer)
1924 RG · 1977 UM
A910 CE
main-belt[1][3] · (outer)[4]
background [5]
Orbital characteristics[3]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc92.70 yr (33,857 d)
Aphelion3.5188 AU
Perihelion1.9556 AU
2.7372 AU
4.53 yr (1,654 d)
0° 13m 3.36s / day
Physical characteristics
Mean diameter
84.78±22.26 km[6]
97.38±1.23 km[7]
97.96±34.85 km[8]
98.015±8.377 km[9]
99.27±3.27 km[10]
99.39±2.3 km[11]
99.6±19.9 km[12]
100.765±1.608 km[13]
105±11 km[14]
Mass(5.14±0.12)×1018 kg[10]
Mean density
10.03±1.02 g/cm3[10]
12.146±0.001 h[15]
12.146 h[16][17]
12.15186±0.00005 h[18]
12.160±0.002 h[19]
12.16 h[19]
Tholen = F[3] · F[20]
SMASS = B[3][4]
B–V = 0.656[3]
U–B = 0.230[3]
9.03[8] · 9.34±0.27[21]

1021 Flammario, provisional designation 1924 RG, is a dark background asteroid from the central regions of the asteroid belt, approximately 100 kilometers (62 miles) in diameter. It was discovered on 11 March 1924, by German astronomer Max Wolf at the Heidelberg-Königstuhl State Observatory in Heidelberg, Germany.[1] The asteroid was named after French astronomer Camille Flammarion.[2] The uncommon F-type asteroid has a rotation period of 12.16 hours.[4]

Orbit and classification

Flammario is a non-family asteroid from the main belt's background population.[5] It orbits the Sun in the central asteroid belt at a distance of 2.0–3.5 AU once every 4 years and 6 months (1,654 days; semi-major axis of 2.74 AU). Its orbit has an eccentricity of 0.29 and an inclination of 16° with respect to the ecliptic.[3]

The asteroid was first observed as A910 CE at Taunton Observatory (803) in February 1910. The body's observation arc begins at the Pulkovo Observatory near Saint Petersburg, Russia, in January 1928, more than four years after its official discovery observation at Heidelberg.[1]

Physical characteristics

In the SMASS classification, Flammario is a "bright" carbonaceous B-type, while it is an uncommon F-type asteroid in the Tholen taxonomy. (The SMASS taxonomic scheme classifies all F-types as B-type asteroids).[3][4] More recent polarimetric observations also characterized the asteroid as a dark F-type.[20]

Rotation period

Several rotational lightcurves of Flammario have been obtained from photometric observations since the 1990s (U=2/2/2).[15][16][17] Analysis of the best-rated lightcurve obtained by French amateur astronomer Laurent Bernasconi in January 2005 gave a rotation period of 12.160 hours with a consolidated brightness amplitude between 0.14 and 0.40 magnitude (U=3-).[4][19]


In 2016, a modeled lightcurve using photometric data from various sources, rendered a similar sidereal period of 12.15186 hours and two spin axes of (32.0°, 22.0°) and (216.0°, 55.0°) in ecliptic coordinates.[18]

Diameter and albedo

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Flammario measures between 84.78 and 105 kilometers in diameter and its surface has a low albedo between 0.04 and 0.05.[6][7][8][9][11][12][13][14]

The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.0458 and a diameter of 99.39 kilometers based on an absolute magnitude of 8.98.[4]

Mass, density and porosity

Flammario has an estimated mass of (5.14±0.12)×1018 kg with a theoretical bulk density of 10.03±1.02 g/cm3 (marked as unrealistically high by the author of the publication) due to its low macroporosity, i.e. the lack of voids within the body.[10] Small Solar System bodies may have 20% of more porosity (which decreases with the size of the body due to self-gravity). The carbonaceous outer-belt asteroids typically show a higher macroporosity than the basaltic, stony asteroids from the inner regions of the asteroid belt.[10]


This minor planet was named after renowned French astronomer Camille Flammarion (1842–1925), who founded the French Astronomical Society (French: Société astronomique de France) and the astronomical journal L'Astronomie in the 1880s. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 98). The lunar crater Flammarion as well as the crater Flammarion on Mars were also named in his honor.[2]


  1. ^ a b c d "1021 Flammario (1924 RG)". Minor Planet Center. Retrieved 13 March 2018.
  2. ^ a b c Schmadel, Lutz D. (2007). "(1021) Flammario". Dictionary of Minor Planet Names – (1021) Flammario. Springer Berlin Heidelberg. p. 88. doi:10.1007/978-3-540-29925-7_1022. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f g h i "JPL Small-Body Database Browser: 1021 Flammario (1924 RG)" (2018-01-27 last obs.). Jet Propulsion Laboratory. Retrieved 13 March 2018.
  4. ^ a b c d e f g "LCDB Data for (1021) Flammario". Asteroid Lightcurve Database (LCDB). Retrieved 13 March 2018.
  5. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 13 March 2018.
  6. ^ a b c d Nugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T.; et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos". The Astrophysical Journal. 814 (2): 13. arXiv:1509.02522. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117. Retrieved 13 March 2018.
  7. ^ 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 13 March 2018. Online catalog
  8. ^ a b c d Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv:1606.08923. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63. Retrieved 13 March 2018.
  9. ^ 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.
  10. ^ a b c d e Carry, B. (December 2012), "Density of asteroids", Planetary and Space Science, 73 (1): 98–118, arXiv:1203.4336, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009 See Table 1.
  11. ^ a b c d Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Archived from the original on 3 June 2016. Retrieved 13 March 2018.
  12. ^ a b c d Alí-Lagoa, V.; Licandro, J.; Gil-Hutton, R.; Cañ; ada-Assandri, M.; Delbo', M.; et al. (June 2016). "Differences between the Pallas collisional family and similarly sized B-type asteroids". Astronomy and Astrophysics. 591: 11. Bibcode:2016A&A...591A..14A. doi:10.1051/0004-6361/201527660. Retrieved 13 March 2018.
  13. ^ 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". The Astrophysical Journal. 791 (2): 11. arXiv:1406.6645. Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121.
  14. ^ a b c d Alí-Lagoa, V.; de León, J.; Licandro, J.; Delbó, M.; Campins, H.; Pinilla-Alonso, N.; et al. (June 2013). "Physical properties of B-type asteroids from WISE data". Astronomy and Astrophysics. 554: 16. arXiv:1303.5487. Bibcode:2013A&A...554A..71A. doi:10.1051/0004-6361/201220680. Retrieved 13 March 2018.
  15. ^ a b Buchheim, Robert K. (December 2005). "Asteroid photometry reports from Altimira Observatory - Winter 2004-2005". The Minor Planet Bulletin. 32 (4): 79–80. Bibcode:2005MPBu...32...79B. ISSN 1052-8091. Retrieved 13 March 2018.
  16. ^ a b Hainaut-Rouelle, M.-C.; Hainaut, O. R.; Detal, A. (July 1995). "Lightcurves of selected minor planets". Astronomy and Astrophysics Supplement. 112: 125. Bibcode:1995A&AS..112..125H. Retrieved 13 March 2018.
  17. ^ a b Schober, H. J.; Erikson, A.; Hahn, G.; Lagerkvist, C. I.; Oja, T. (November 1993). "Physical Studies of Asteroids. Part XXVI. Rotation and Photoelectric Photometry of Asteroids 323, 350, 582, 1021 and 1866". Astronomy and Astrophysics Supplement. 101 (3): 507. Bibcode:1993A&AS..101..499S. Retrieved 13 March 2018.
  18. ^ 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.
  19. ^ a b c Behrend, Raoul. "Asteroids and comets rotation curves – (1021) Flammario". Geneva Observatory. Retrieved 13 March 2018.
  20. ^ a b Belskaya, I. N.; Fornasier, S.; Tozzi, G. P.; Gil-Hutton, R.; Cellino, A.; Antonyuk, K.; et al. (March 2017). "Refining the asteroid taxonomy by polarimetric observations". Icarus. 284: 30–42. Bibcode:2017Icar..284...30B. doi:10.1016/j.icarus.2016.11.003. Retrieved 13 March 2018.
  21. ^ 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 13 March 2018.

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