25 Phocaea

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25 Phocaea
25Phocaea (Lightcurve Inversion).png
Lightcurve-base 3D-model of Phocaea
Discovery [1][2]
Discovered by J. Chacornac
Discovery site Marseille Obs.
Discovery date 6 April 1853
Designations
MPC designation (25) Phocaea
Pronunciation /fˈsə/ foh-SEE
Named after
Phōcæa[3]
(ancient Greek city)
1956 GC
main-belt · (inner)
Phocaea[4][5]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc 157.44 yr (57,504 days)
Aphelion 3.0104 AU
Perihelion 1.7899 AU
2.4001 AU
Eccentricity 0.2543
3.72 yr (1,358 days)
13.891°
0° 15m 54.36s / day
Inclination 21.606°
214.14°
90.245°
Physical characteristics
Dimensions 61.05±2.46 km[6]
61.054±2.463 km[6]
71 km[7]
75.13±3.6 km[4][8]
80.19±4.66 km[9]
82±8 km[10]
83.21±0.96 km[11]
Mass (5.99 ± 0.60) × 1017 kg[9]
Mean density
2.21±0.44 g/cm3[9]
9.92±0.05 h[12]
9.9341±0.0002 h[13]
9.935±0.003 h[14]
9.945±0.002 h[15]
9.945 h[16]
9.95±0.01 h[12]
0.189±0.005[11]
0.2310±0.024[4][8]
0.350±0.046[6]
Tholen = S[1]
SMASS = S[1][4] · S[17]
B–V = 0.932 [1]
U–B = 0.513 [1]
7.83[1][4][6][8][11] · 7.90±0.25[18]

25 Phocaea (/fˈsə/ foh-SEE) is a stony asteroid from the inner regions of the asteroid belt, approximately 75 kilometers in diameter. It is the parent body of the Phocaea family. Discovered by Jean Chacornac in 1853, it was named after the ancient Greek city of Phocaea.

Discovery and naming[edit]

Phocaea was discovered on 6 April 1853, by French astronomer Jean Chacornac at Marseille Observatory in southern France.[2] It was his first asteroid discovery out of a total of six, the asteroid was named after the ancient Ionian Greek city of Phocaea, modern-day Foça in Turkey, where the founders of Marseille came from.[3] The naming was proposed by French astronomer Benjamin Valz.[3]

Classification and orbit[edit]

Phocaea is the parent body and namesake of the Phocaea family (701), a large asteroid family of stony asteroids in the inner main belt.[5][19]:23

It orbits the Sun at a distance of 1.8–3.0 AU once every 3 years and 9 months (1,358 days). Its orbit has an eccentricity of 0.25 and an inclination of 22° with respect to the ecliptic.[1] The body's observation arc begins at Vienna Observatory in March 1860, almost 7 years after its official discovery observation at Marseille.[2]

Physical characteristics[edit]

Spectral type[edit]

Phocaea is a stony S-type asteroid in both the Tholen and SMASS classification,[1] and has also been characterized as such by others.[17]

Lightcurves[edit]

Photometric observations of this asteroid at the Organ Mesa Observatory in Las Cruces, New Mexico during 2010 gave a lightcurve with a period of 9.9341 ± 0.0002 hours. The brightness near the deepest minimum of the light curve showed changes with phase angle, which is the result of shadows extending across surface irregularities.[13] Several other lightcurves have also been obtained.[4]

Phocaea has also been studied by radar.[20]

Diameter and albedo[edit]

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, Phocaea measures between 61.05 and 83.21 kilometers in diameter and its surface has an albedo between 0.189 and 0.350.[6][7][8][10][11]

The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.2310 and a diameter of 75.13 kilometers based on an absolute magnitude of 7.83.[4]

Mass and density[edit]

The asteroid has a mass of (5.99 ± 0.60) × 1017 kilograms and a mean density of 2.21±0.44 grams per cubic centimeters, which lies approximately in between lime stone and concrete/gravel.[9]

References[edit]

  1. ^ a b c d e f g h i "JPL Small-Body Database Browser: 25 Phocaea" (2017-08-19 last obs.). Jet Propulsion Laboratory. Retrieved 1 November 2017. 
  2. ^ a b c "25 Phocaea". Minor Planet Center. Retrieved 1 November 2017. 
  3. ^ a b c Schmadel, Lutz D. (2007). Dictionary of Minor Planet Names – (25) Phocaea. Springer Berlin Heidelberg. p. 17. ISBN 978-3-540-00238-3. Retrieved 1 November 2017. 
  4. ^ a b c d e f g "LCDB Data for (25) Phocaea". Asteroid Lightcurve Database (LCDB). Retrieved 1 November 2017. 
  5. ^ a b "Small Bodies Data Ferret". Nesvorny HCM Asteroid Families V3.0. Retrieved 1 November 2017. 
  6. ^ a b c d e 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 1 November 2017. 
  7. ^ a b Marchis, F.; Kaasalainen, M.; Hom, E. F. Y.; Berthier, J.; Enriquez, J.; Hestroffer, D.; et al. (November 2006). "Shape, size and multiplicity of main-belt asteroids. I. Keck Adaptive Optics survey". Icarus. 185 (1): 39–63. Bibcode:2006Icar..185...39M. doi:10.1016/j.icarus.2006.06.001. Retrieved 1 November 2017. 
  8. ^ 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. Bibcode:2004PDSS...12.....T. Retrieved 1 November 2017. 
  9. ^ a b c d Carry, B. (December 2012), "Density of asteroids" (PDF), Planetary and Space Science, 73, pp. 98–118, arXiv:1203.4336Freely accessible, Bibcode:2012P&SS...73...98C, doi:10.1016/j.pss.2012.03.009  See Table 1.
  10. ^ a b Lim, Lucy F.; McConnochie, Timothy H.; Bell, James F.; Hayward, Thomas L. (February 2005). "Thermal infrared (8 13 mum) spectra of 29 asteroids: the Cornell Mid-Infrared Asteroid Spectroscopy (MIDAS) Survey". Icarus. 173 (2): 385–408. Bibcode:2005Icar..173..385L. doi:10.1016/j.icarus.2004.08.005. Retrieved 1 November 2017. 
  11. ^ 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 1 November 2017. 
  12. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (25) Phocaea". Geneva Observatory. Retrieved 1 November 2017. 
  13. ^ a b Pilcher, Frederick (April 2011). "Rotation Period Determinations for 25 Phocaea, 140 Siwa, 149 Medusa 186 Celuta, 475 Ocllo, 574 Reginhild, and 603 Timandra". The Minor Planet Bulletin. 38 (2): 76–78. Bibcode:2011MPBu...38...76P. ISSN 1052-8091. Retrieved 1 November 2017. 
  14. ^ Pilcher, Frederick (October 2009). "New Lightcurves of 8 Flora, 13 Egeria, 14 Irene, 25 Phocaea 40 Harmonia, 74 Galatea, and 122 Gerda". The Minor Planet Bulletin. 36 (4): 133–136. Bibcode:2009MPBu...36..133P. ISSN 1052-8091. Retrieved 1 November 2017. 
  15. ^ Buchheim, Robert K. (September 2007). "Lightcurves of 25 Phocaea, 468 Lina, 482 Petrina 551 Ortrud, 741 Botolphia, 834 Burnhamia, 2839 Annette, and 3411 Debetencourt". The Minor Planet Bulletin. 34 (3): 68–71. Bibcode:2007MPBu...34...68B. ISSN 1052-8091. Retrieved 1 November 2017. 
  16. ^ Groeneveld, Ingrid; Kuiper, Gerard P. (September 1954). "Photometric Studies of Asteroids. I". Astrophysical Journal: 200. Bibcode:1954ApJ...120..200G. doi:10.1086/145904. Retrieved 1 November 2017. 
  17. ^ 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 24 October 2017. 
  18. ^ 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:1506.00762Freely accessible. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 1 November 2017. 
  19. ^ Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). "Identification and Dynamical Properties of Asteroid Families" (PDF). Asteroids IV: 297–321. arXiv:1502.01628Freely accessible. Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016. Retrieved 1 November 2017. 
  20. ^ "Radar-Detected Asteroids and Comets". NASA/JPL Asteroid Radar Research. 30 October 2017. Retrieved 1 November 2017. 

External links[edit]