1453 Fennia, provisional designation 1938 ED1, is a stony Hungaria
asteroid and synchronous
binary system from the innermost regions of the
asteroid belt, approximately 7 kilometers in diameter. Discovered by
Yrjö Väisälä at the
Turku Observatory in 1938,[23] the asteroid was later named after the
Nordic country of
Finland.[2] The system's
minor-planet moon was discovered in 2007. It has a derived diameter of 1.95 kilometers and is orbiting its primary every 23.55 hours.[6][7]
Discovery
Fennia was discovered on 8 March 1938, by Finnish astronomer
Yrjö Väisälä at the
Iso-Heikkilä Observatory in Turku, southwest Finland.[23] Fifteen days later, it was independently discovered by Soviet astronomer
Grigory Neujmin at the
Simeiz Observatory on the Crimean peninsula, which also served as a confirmation of the first observation.[1][2] The
Minor Planet Center only recognizes the first discoverer.[23]
It orbits the Sun in the
inner main-belt at a distance of 1.8–2.0
AU once every 2 years and 7 months (954 days). Its orbit has an
eccentricity of 0.03 and an
inclination of 24
° with respect to the
ecliptic.[1] The body's
observation arc begins at the discovering observatory (or at Simeiz Observatory), 15 days after its official discovery observation at Turku.[23]
Since 1991, a large number of rotational
lightcurves of Fennia have been obtained from photometric observations. Lightcurve analysis gave a consolidated
rotation period of 4.4121 hours with a brightness amplitude between 0.10 and 0.20
magnitude (U=0/3/3/3/3/3-).[7][13][11][14][15][16][17][18][b][a] Due to its relatively low brightness amplitude, Fennia is likely
spheroidal in shape.
Moon
In 2007, these
photometric lightcurve observations revealed that Fennia is a synchronous
binary asteroid, orbited by a
minor-planet moon.[5][6] The moon has an orbital period of 22.99 hours,[11][13][b] later revised to 23.55 hours.[7][a] It is at least a quarter the size of Fennia itself – a secondary-to-primary mean-diameter ratio of 0.28±0.02) – which translates into a diameter of 1.95±0.18 kilometers based on current estimates.[6]
The Johnston's archive derives a diameter of 6.96 kilometers,[6] while Collaborative Asteroid Lightcurve Link adopts an albedo of 0.244 and a diameter of 7.32 kilometers using an
absolute magnitude of 12.835, taken from the revised WISE-results.[3][11]
^
abcLightcurve plot of 1453 Fennia, Palmer Divide Station, California, Brian D. Warner (2016). rotation period 4.412±0.002 hours with a brightness amplitude of 0.19 mag, and P2-chart with an orbital period of 23.55±0.05 hours. Summary figures at
LCDB
^
abcLightcurve plot of 1453 Fennia, Palmer Divide Observatory, Colorado, Brian D. Warner (2007) rotation period 4.4121±0.0001 hours with a brightness amplitude of 0.10±0.01 mag, including primary–secondary mutual eclipsing/occultation event chart with an
orbital period of 22.99±0.05. Summary figures at
LCDB
^
abcdeWarner, Brian D. (July 2016). "Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2015 December - 2016 April". The Minor Planet Bulletin. 43 (3): 227–233.
Bibcode:
2016MPBu...43..227W.
ISSN1052-8091.
^
abcdNugent, 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.
^
abcdMasiero, 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.
^
abcdefghijkWarner, Brian D.; Harris, Alan W.; Pravec, Petr; Stephens, Robert D.; Pray, Donald P.; Cooney, Walter R. Jr.; et al. (June 2008). "1453 Fennia: A Hungaria Binary". The Minor Planet Bulletin. 35 (2): 73–74.
Bibcode:
2008MPBu...35...73W.
ISSN1052-8091.
^
abcdUsui, 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. (
online,
AcuA catalog p. 153)
^
abcWarner, B. D.; Harris, A. W.; Pravec, P.; Stephens, R. D.; Pray, D.; Cooney, W.; et al. (December 2007). "(1453) Fennia". Central Bureau Electronic Telegrams. 1150 (1150): 1.
Bibcode:
2007CBET.1150....1W.
^
abcPravec, P.; Scheirich, P.; Vokrouhlický, D.; Harris, A. W.; Kusnirák, P.; Hornoch, K.; et al. (March 2012). "Binary asteroid population. 2. Anisotropic distribution of orbit poles of small, inner main-belt binaries". Icarus. 218 (1): 125–143.
Bibcode:
2012Icar..218..125P.
doi:
10.1016/j.icarus.2011.11.026.
^
abHiggins, David; Oey, Julian; Pravec, Petr (January 2011). "Period Determination of Binary Asteroid Targets Observed at Hunters Hill Observatory: May-September 2009". The Minor Planet Bulletin. 38 (1): 46–49.
Bibcode:
2011MPBu...38...46H.
ISSN1052-8091.
^
abSantana-Ros, Toni; Marciniak, Anna; Bartczak, Prezemyslaw (July 2016). "Gaia-GOSA: A Collaborative Service for Asteroid Observers". The Minor Planet Bulletin. 43 (3): 205–207.
Bibcode:
2016MPBu...43..205S.
ISSN1052-8091.
^
abcWisniewski, W. Z.; Michalowski, T. M.; Harris, A. W.; McMillan, R. S. (March 1995). "Photoelectric Observations of 125 Asteroids". Abstracts of the Lunar and Planetary Science Conference. 26: 1511.
Bibcode:
1995LPI....26.1511W.