(110) Lydia

110 Lydia
110Lydia (Lightcurve Inversion).png
Lightcurve-based 3D-model of Lydia
Discovered byAlphonse Borrelly
Discovery date19 April 1870
(110) Lydia
Named after
Orbital characteristics[2]
Epoch 31 July 2016 (JD 2457600.5)
Uncertainty parameter 0
Observation arc145.80 yr (53,255 d)
Aphelion2.9539 AU (441.90 Gm)
Perihelion2.51115 AU (375.663 Gm)
2.7325 AU (408.78 Gm)
4.52 yr (1649.9 d)
17.99 km/s
0° 13m 5.52s / day
Physical characteristics
Mass6.7×1017 kg
Equatorial surface gravity
0.0241 m/s2
Equatorial escape velocity
0.0455 km/s
  • 10.927 h (0.4553 d)[2]
  • 10.9258 hours[4]
Temperature~168 K

Lydia (minor planet designation: 110 Lydia) is a large belt asteroid with an M-type spectrum,[5] and thus may be metallic in composition, consisting primarily of nickel-iron. It was discovered by French astronomer Alphonse Borrelly on 19 April 1870[6] and was named for Lydia, the Asia Minor country populated by Phrygians.[7] The Lydia family of asteroids is named after it.

Observations made during 1958–1959 at the McDonald Observatory and in 1969 at the Kitt Peak National Observatory found an uneven light curve with a period of 10.9267 hours.[8] In the late 1990s, a network of astronomers worldwide used light curves to derive spin states and shape models of 10 new asteroids, including (110) Lydia. They obtained a period of 10.92580 hours, with the brightness varying by no more than 0.2 in magnitude.[4]

In the Tholen classification system, it is categorized as an M-type asteroid, while the Bus asteroid taxonomy system lists it as an Xk asteroid.[9] Absorption features in the near infrared are attributed to low-iron, low-calcium orthopyroxene minerals. Water content on the surface is estimated at 0.14–0.27 by mass fraction (wt%).[10] Measurements of the thermal inertia of 110 Lydia give a value between 70 and 200 J·m−2·K−1·s−1/2, compared to 50 for lunar regolith and 400 for coarse sand in an atmosphere.[3] It is a likely interloper in the Padua family of minor planets that share similar dynamic properties.[11]

Lydia occulted a dim star on 18 September 1999.


  1. ^ Noah Webster (1884) A Practical Dictionary of the English Language
  2. ^ a b c d e Yeomans, Donald K., "110 Lydia", JPL Small-Body Database Browser, NASA Jet Propulsion Laboratory, retrieved 12 May 2016.
  3. ^ a b c d Delbo', Marco; Tanga, Paolo (February 2009), "Thermal inertia of main belt asteroids smaller than 100 km from IRAS data", Planetary and Space Science, vol. 57, no. 2, pp. 259–265, arXiv:0808.0869, Bibcode:2009P&SS...57..259D, doi:10.1016/j.pss.2008.06.015.
  4. ^ a b Durech, J.; et al. (April 2007), "Physical models of ten asteroids from an observers' collaboration network", Astronomy and Astrophysics, vol. 465, no. 1, pp. 331–337, Bibcode:2007A&A...465..331D, doi:10.1051/0004-6361:20066347.
  5. ^ a b DeMeo, Francesca E.; et al. (2011), "An extension of the Bus asteroid taxonomy into the near-infrared" (PDF), Icarus, 202 (1): 160–180, Bibcode:2009Icar..202..160D, doi:10.1016/j.icarus.2009.02.005, archived from the original (PDF) on 17 March 2014, retrieved 11 December 2013. See appendix A.
  6. ^ "Numbered Minor Planets 1–5000", Discovery Circumstances, IAU Minor Planet center, retrieved 7 April 2013.
  7. ^ Schmadel, Lutz D. (2003), Dictionary of Minor Planet Names (5th ed.), Springer, p. 23, ISBN 3-540-00238-3.
  8. ^ Taylor, R. C.; et al. (March 1971), "Minor Planets and Related Objects. VI. Asteroid (110) Lydia", Astronomical Journal, vol. 76, p. 141, Bibcode:1971AJ.....76..141T, doi:10.1086/111097.
  9. ^ DeMeo, Francesca E.; et al. (July 2009), "An extension of the Bus asteroid taxonomy into the near-infrared" (PDF), Icarus, vol. 202, no. 1, pp. 160–180, Bibcode:2009Icar..202..160D, doi:10.1016/j.icarus.2009.02.005, archived from the original (PDF) on 17 March 2014, retrieved 8 April 2013. See appendix A.
  10. ^ Hardersen, Paul S.; Gaffey, Michael J.; Abell, Paul A. (January 1983), "Near-IR spectral evidence for the presence of iron-poor orthopyroxenes on the surfaces of six M-type asteroids", Icarus, vol. 175, no. 1, pp. 141–158, Bibcode:2005Icar..175..141H, doi:10.1016/j.icarus.2004.10.017.
  11. ^ Carruba, V. (May 2009), "The (not so) peculiar case of the Padua family", Monthly Notices of the Royal Astronomical Society, 395 (1): 358–377, Bibcode:2009MNRAS.395..358C, doi:10.1111/j.1365-2966.2009.14523.x.

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