Flora-asteroid

För andra betydelser, se Flora.
Flora-familjens struktur och plats inom asteroidbältet.

Flora-asteroiderna, eller Flora-familjen, är en stor grupp stenasteroider (S-typ) som befinner sig i den innersta Kirkwoodluckan i asteroidbältet. Det är en av de största asteroidfamiljerna med mer än 13000 kända medlemmar, eller 3,5 procent av huvudbältets totala massa.[1]

Flora-asteroiderna befinner sig på ett perihelieavstånd av ungefär 2,17 AU med ett aphelieavstånd av ungefär 2,33 AU.[1]

Familjen har fått namn efter sin största medlem, 8 Flora, en ljus asteroid som har ungefär 85 procent av asteroidfamiljens totala massa. Merparten av den övriga massan återfinns hos asteroiden 43 Ariadne.

Noter

  1. ^ [a b] D. Nesvorný, M. Broz, V. Carruba (december 2014) (på engelska). Identification and Dynamical Properties of Asteroid Families. sid. 297–321. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN 978-08-16532-13-1. Bibcode: 2015aste.book..297N 

Media som används på denna webbplats

Flora family.png
(c) Deuar at the English Wikipedia, CC-BY-SA-3.0
Diagrams showing the location and characteristics of the Flora family of asteroids. Where circles are plotted, their diameter is proportional to the mean diameter of the asteroid.

In the top diagrams, the proper orbital elements are plotted (inclination ip vs. semi-major axis ap on the left, and inclination ip vs. eccentricity ep on the right) for numbered asteroids in the main belt.

In the bottom enlargements, one has:

  • core family members (shown in red) are those identified by the 1995 Zappala (V. Zappala et al, Icarus Vol. 116, p. 291 (1995)) HCM method analysis. The data set is here.
  • outer family members (shown in purple) were identified by the same analysis, but are somewhat less certain to be members (were given a quality tag of "1" in the data-set)
  • interlopers (shown in green) were identified either:
    • by the spectroscopic analysis of Florczak (M. Florczak et al A Visible Spectroscopic Survey of the Flora Clan, Icarus Vol. 133, p. 233 (1998)),
    • and also by inspection of the PDS asteroid taxonomy data set for non S-type members of the above Zappala 1995 data-set.
  • numbered asteroids in general (shown as small blue dots), from the AstDys database.

The location of asteroids that are very large and/or explicitly named on the plot is shown by a light cross within the circle.

Asteroid diameters were obtained from two sources:

  • (thick circles): From the IRAS survey, when available (data set here).
  • (thin circles): Otherwise, by assuming an albedo of 0.243 (same as 8 Flora), and estimating from absolute magnitudes from the AstOrb database here.

The diagrams were created by me (Piotr Deuar) using proper element data for 96944 minor planets, which was obtained from the AstDys site. Data was dated March 2005, calculation was by Z. Knezevic and A. Milani.

The top left plot is a slightly modified reduced version of :Image:Asteroid_proper_elements_i_vs_a.png.