View source for 8 Flora

{{Short description|Large main-belt asteroid}}
{{Use dmy dates|date=October 2019}}
{{Infobox planet
| minorplanet = yes
| background = #D6D6D6
| name = 8 Flora
| image = 8 Flora VLT (2021), deconvolved.pdf
| image_size = 
| caption = 
| symbol = [[File:Flora symbol (bold).svg|24px]] (historical)
| discoverer = [[John Russell Hind|J.R. Hind]]
| discovered = 18 October 1847
| mpc_name = (8) Flora
| alt_names = 
| adjectives = Florian {{IPAc-en|ˈ|f|l|ɔər|i|ə|n}}
| pronounced = {{IPAc-en|ˈ|f|l|ɔər|ə}}
| named_after = [[Flora (mythology)|Flōra]]
| mp_category = [[Asteroid belt|Main belt]] ([[Flora family]])
| orbit_ref = <ref name=jpldata />
| epoch = 17.0&nbsp;October 2024<br/>([[Julian day|JD]]&nbsp;2460600.5)
| semimajor = {{Convert|2.20|AU|e6km|abbr=unit}}
| perihelion = {{Convert|1.86|AU|e6km|abbr=unit}}
| time_periastron = 1 February 2024
| aphelion = {{Convert|2.55|AU|e6km|abbr=unit|lk=on}}
| eccentricity = 0.15658
| period = 3.27 [[Julian year (astronomy)|yr]] (1192.70 d)
| inclination = 5.890°
| asc_node = 110.85°
| arg_peri = 285.4°
| mean_anomaly = 78.2°
| moid = {{Convert|0.873|AU|e6km|abbr=unit}}
| jupiter_moid = {{Convert|2.877|AU|e6km|abbr=unit}}
| tisserand = 3.642
| p_orbit_ref = <ref name=Flora-POE />
| p_semimajor = 2.2014
| p_eccentricity = 0.1449
| p_inclination = 5.574°
| p_mean_motion = 110.2
| perihelion_rate = 32.017
| node_rate = −35.51
| dimensions = ({{val|154|×|148|×|127|u=km}}) ± ({{val|7|×|6|×|4|u=km}})<ref name=VLT/><br>{{val|136|×|136|×|113|ul=km}}<ref name=Baer/><br />{{val|145|×|145|×|120|u=km}}<ref name="Torppa2003" />
| mean_diameter = {{val|146|2|u=km}}<ref name=VLT>P. Vernazza et al. (2021) VLT/SPHERE imaging survey of the largest main-belt asteroids: Final results and synthesis. ''Astronomy & Astrophysics'' 54, A56</ref><br /> {{val|128|u=km}}<ref name=Baer/><br>{{val|147.491|1.025|u=km}}<ref name=jpldata/>
| flattening = 0.18{{efn|1=Flattening derived from the maximum aspect ratio (c/a): <math>f=1-\frac{c}{a}</math>, where (c/a) = {{val|0.82|0.05}}.<ref name=VLT/>}}
| mass = {{val|4.0|1.6|e=18|u=kg}}<ref name=VLT/><br />{{val|6.62|0.84|e=18|u=kg}}{{refn|group=lower-alpha|{{val|3.33|0.42|e=−12|u={{Solar mass}}}}}}<ref name="Baer2011">James Baer, Steven Chesley & Robert Matson (2011) "Astrometric masses of 26 asteroids and observations on asteroid porosity." ''The Astronomical Journal'', Volume 141, Number 5</ref>
| density = {{val|2.4|1.0|u=g/cm3}}<ref name=VLT/><br />{{val|3.04|1.39|u=g/cm3}}<ref name="Baer2011"/>
| rotation = {{cvt|12.865|h|d}}<ref name=jpldata/>
| albedo = 0.224 (calculated)<ref name=VLT/><br />{{val|0.226|0.041}}<ref name=jpldata/>
| spectral_type = [[S-type asteroid|S]]<ref name=jpldata/>
| magnitude = 7.9<ref name="Pasachoff1983" /> to 11.6
| abs_magnitude = 6.54<ref name=VLT/><br>6.61<ref name=jpldata/>
| angular_size = 0.21" <!-- Horizons 2007-Nov-18 --> to 0.053"
}}

'''8 Flora''' is a large, bright [[Asteroid belt|main-belt]] [[asteroid]]. It is the innermost ''large'' asteroid: no asteroid closer to the Sun has a diameter above 25 kilometers (20% that of Flora), and not until 20-km [[149 Medusa]] was discovered was an asteroid known to orbit at a closer mean distance.<ref>Binsel, Richard P.; Gehrels, Tom and Matthews, Mildred Shapley (editors); ''Asteroids II''; published 1989 by University of Arizona Press; pp. 1038-1040. {{ISBN|0-8165-1123-3}}</ref> It is the seventh-brightest asteroid with a mean [[Opposition (astronomy)|opposition]] [[apparent magnitude|magnitude]] of +8.7.<ref>{{Cite web |date= |title=JAS: The Brightest Asteroids |url=http://www.jas.org.jo/ast.html |archive-url=https://web.archive.org/web/20110825060222/http://www.jas.org.jo/ast.html |archive-date=25 August 2011 |access-date= }}</ref> Flora can reach a magnitude of +8.1 at a favorable opposition near [[perihelion]], such as occurred in November 2020 when it was {{Convert|0.88|AU|e6km LD|abbr=unit|lk=on}} from Earth.<ref name="Horizons2020"/>

==Discovery and naming==
Flora was discovered by [[John Russell Hind|J. R. Hind]] on 18 October 1847. It was his second asteroid discovery after [[7 Iris]].{{citation needed|date=October 2020}}

The name Flora was proposed by [[John Herschel]], from [[Flora (goddess)|Flora]], the [[Roman mythology|Latin goddess]] of flowers and gardens, wife of [[Zephyrus]] (the [[personification]] of the West wind), and mother of Spring. The Greek equivalent is [[Chloris]], who has her own asteroid, [[410 Chloris]], but in Greek 8 Flora is also called 8 Chloris (8 Χλωρίς).{{citation needed|date=October 2020}}
The old iconic symbol for 8 Flora has been variously rendered as [[File:Flora symbol (fixed width).svg|24px]], [[File:Flora symbol (simple, fixed width).svg|24px]], etc. It is in the pipeline for [[Unicode]] 17.0 as U+1CEC2 𜻂 ([[File:Flora symbol (fixed width).svg|12px]]).<ref name=astunicode>{{cite web |url=https://www.unicode.org/L2/L2023/23207-historical-asteroids.pdf |title=Unicode request for historical asteroid symbols |last1=Bala |first1=Gavin Jared |last2=Miller |first2=Kirk |date=18 September 2023 |website=unicode.org |publisher=Unicode |access-date=26 September 2023 |quote=}}</ref><ref name=pipeline>{{cite web |url=https://unicode.org/alloc/Pipeline.html |title=Proposed New Characters: The Pipeline |author=Unicode |date= |website=unicode.org |publisher=The Unicode Consortium |access-date=6 November 2023 |quote=}}</ref>

==Characteristics==
[[File:FloraOrbit.png|thumb|left|The orbit of 8 Flora compared with the orbits of Earth, Mars and Jupiter]][[File:Moon and Asteroids 1 to 10.svg|thumb|left|Size comparison: the first 10 asteroids profiled against Earth's [[Moon]]. Flora is third from the right.]]
Lightcurve analysis indicates that Flora's pole points towards [[ecliptic coordinate system|ecliptic coordinates]] (β, λ) = (16°, 160°)  with a 10° uncertainty.<ref name="Torppa2003" /> This gives an [[axial tilt]] of 78°, plus or minus ten degrees.

Flora is the parent body of the [[Flora family]] of asteroids, and by far the largest member, comprising about 80% of the total mass of this family. Nevertheless, Flora was almost certainly disrupted by the impact(s) that formed the family, and is probably a gravitational aggregate of most of the pieces.{{Citation needed|date=November 2008}}

Flora's [[spectrum]] indicates that its surface composition is a mixture of [[silicate]] rock (including [[pyroxene]] and [[olivine]]) and [[nickel]]-[[iron]] metal. Flora, and the whole [[Flora family]] generally, are good candidates for being the parent bodies of the [[L chondrite]] meteorites.<ref name="Nesvorny">{{cite journal| first=D.| last= Nesvorný| title=The Flora Family: A Case of the Dynamically Dispersed Collisional Swarm?| journal=Icarus| volume= 157| issue=1| pages= 155–172| date=2002| doi=10.1006/icar.2002.6830| bibcode=2002Icar..157..155N|display-authors=etal}}</ref> This meteorite type comprises 35% of meteorites impacting the [[Earth]].<ref name="nhm">{{cite book|chapter-url=https://www.nhm.ac.uk/our-science/data/metcat/search/metsPerGroup.dsml|title=The Catalogue of Meteorites|date=2022 |publisher=Natural History Museum|doi=10.5519/tqfuwle7 |access-date=28 May 2020 |last1=Grady |first1=Monica |chapter=Meteorites }}</ref>

==Observational history ==
During an observation on 25 March 1917, 8 Flora was mistaken for the 15th-magnitude star [[TU Leonis]], which led to that star's classification as a [[cataclysmic variable star|U Geminorum cataclysmic variable]] star.<ref name="TU Leonis" />  Flora had come to opposition on 1917 February 13, 40 days earlier.<ref name="TU Leonis" /> This mistake was uncovered only in 1995.<ref name="TU Leonis">{{cite journal| bibcode=1996A&A...312..496S|
title=TU Leonis = (8) Flora: the non-existence of a U Geminorum star| last=Schmadel| first=L. D.|author2= Schmeer, P.|author3= Börngen, F.| journal=Astron. Astrophys.| volume= 312| pages= 496|date=August 1996}}</ref><ref>{{cite web| url=http://cbat.eps.harvard.edu/iauc/06100/06174.html#Item1| title=IAUC 6174}}</ref>

On 26 July 2013, Flora at magnitude 8.8 occulted the star 2UCAC 22807162 over parts of South America, Africa, and Asia.<ref>{{Cite web |date= |title=(8) Flora / 2UCAC 22807162 event on 2013 Jul 26, 00:18 UT |url=http://www.asteroidoccultation.com/2013_07/0726_8_29978.htm |archive-url=https://archive.today/20130724210247/http://www.asteroidoccultation.com/2013_07/0726_8_29978.htm |archive-date=24 July 2013 |access-date= |website=asteroidoccultation.com}}</ref>

==Popular culture==
In the 1968 [[science-fiction film]] ''[[The Green Slime]]'', an orbital perturbation propels the asteroid Flora into a collision course with Earth.

==Notes==
{{notelist}}

==References==
{{Reflist|refs=

<ref name=jpldata>{{cite web
  |quote=2024-11-09 last obs
  |title=JPL Small-Body Database Browser: 8 Flora
  |url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=8
  |access-date=2024-12-20}}</ref>

<ref name=Baer>
{{cite web
  |date=2008
  |title=Recent Asteroid Mass Determinations
  |publisher=Personal Website
  |author=Jim Baer
  |url=http://home.earthlink.net/~jimbaer1/astmass.txt
  |access-date=2008-11-27
  |archive-url=https://web.archive.org/web/20130702212735/http://home.earthlink.net/~jimbaer1/astmass.txt
  |archive-date=2013-07-02
  |url-status=dead
  }}</ref>

<ref name=Flora-POE>{{cite web
   |title=AstDyS-2 Flora Synthetic Proper Orbital Elements
   |publisher=Department of Mathematics, University of Pisa, Italy
   |url=https://newton.spacedys.com/astdys/index.php?pc=1.1.6&n=8
   |access-date=2011-10-01}}</ref>

<ref name="Torppa2003">{{Cite journal
  |display-authors = 6
  |first1     = Johanna |last1 = Torppa
  |first2     = Mikko |last2 = Kaasalainen
  |first3     = Tadeusz |last3 = Michalowski
  |first4     = Tomasz |last4 = Kwiatkowski
  |first5     = Agnieszka |last5 = Kryszczynska
  |first6     = Peter |last6 = Denchev
  |first7     = Richard |last7 = Kowalski
  |date       = August 2003
  |title      = Shapes and rotational properties of thirty asteroids from photometric data
  |journal    = Icarus
  |volume     = 164
  |issue      = 2
  |pages      = 346–383
  |bibcode    = 2003Icar..164..346T
  |doi        = 10.1016/S0019-1035(03)00146-5
  |citeseerx = 10.1.1.694.1087 |s2cid = 119609765 }}</ref>

<ref name="Pasachoff1983">{{cite book |author=Donald H. Menzel |author2=Jay M. Pasachoff |name-list-style=amp |date=1983 |title=A Field Guide to the Stars and Planets |edition=2nd |publisher=[[Houghton Mifflin]] |pages=[https://archive.org/details/fieldguidetostar00menz_0/page/391 391] |location=Boston, MA |isbn=0-395-34835-8 |url-access=registration |url=https://archive.org/details/fieldguidetostar00menz_0/page/391 }}</ref>

<ref name="Horizons2020">{{cite web
  |title=Horizons Batch for November 2020
  |publisher=[[JPL Horizons On-Line Ephemeris System|JPL Horizons]]
  |url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27Flora%27&START_TIME=%272020-10-31%27&STOP_TIME=%272020-11-02%27&STEP_SIZE=%271%20day%27&QUANTITIES=%279,19,20,23,29,39%27
  |accessdate=2022-11-17}}</ref>

<!--<ref name=Gaffey1984>{{cite journal
  |last=Gaffey |first=Michael
  |title=Rotational spectral variations of asteroid (8) Flora: Implications for the nature of the S-type asteroids and for the parent bodies of the ordinary chondrites
  |journal=Icarus|volume=60
  |issue=1 |pages=83–114 |date=1984
  |doi=10.1016/0019-1035(84)90140-4|bibcode=1984Icar...60...83G}}</ref>-->

}} <!-- end of reflist -->

==External links==
*[http://www.rni.helsinki.fi/~mjk/thirty.pdf shape model deduced from lightcurve]
* [http://adsabs.harvard.edu//full/seri/MNRAS/0008//0000082.000.html "Announcement of discovery of Flora", MNRAS '''8''' (1848) 82]
* {{AstDys|8}}
* {{JPL small body}}

{{Minor planets navigator |7 Iris |number=8 |9 Metis}}
{{Small Solar System bodies}}
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{{DEFAULTSORT:000008}}
[[Category:Flora asteroids]]
[[Category:Discoveries by John Russell Hind|Flora]]
[[Category:Named minor planets|Flora]]
[[Category:S-type asteroids (Tholen)]]
[[Category:Astronomical objects discovered in 1847|18471018]]
[[Category:Flora (mythology)]]