View source for 511 Davida

{{Short description|Large asteroid in the asteroid belt}}
{{Use mdy dates|date=June 2013}}
{{Infobox planet
   | bgcolour=#D6D6D6
 | name=511 Davida
 | image=511 Davida VLT (2021), deconvolved.pdf
 | image_size = 
 | caption=
 | discoverer=[[Raymond Smith Dugan|R. S. Dugan]]
 | discovered=May 30, 1903
 | mpc_name=(511) Davida
 | alt_names=1903 LU
 | pronounced = {{IPAc-en|d|ə|ˈ|v|i:|d|ə}}<!--\də-VEE-də\ is the pronunciation used by astronomers who work on this asteroid. See talk.-->,<ref>John Daintith & William Gould, eds. (2006) ''The Facts On File Dictionary of Astronomy''. 5th edition. Infobase Publishing.</ref> Latin ''Dāvīda''
 | adjective = Davidian {{IPAc-en|d|ə|ˈ|v|ɪ|d|i|ə|n}}<ref>{{MW|Davidian}}</ref>
 | named_after = [[David Peck Todd]]
 | mp_category=[[main-belt]]{{·}}{{small|([[Kirkwood gap|outer]])}}<br />[[Meliboea family|Meliboea]]<ref name="Ferret" />
 | orbit_ref = <ref name=JPL>[https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Davida JPL data] Retrieved 2021-09-29</ref>
 | epoch=July 01, 2021 <br />([[Julian day|JD]] 2459396.5, heliocentric)
 | aphelion=3.759 [[Astronomical unit|AU]]
 | perihelion=2.569 AU
 | semimajor=3.163 AU
 | eccentricity=0.188
 | period=5.626 [[Julian year (astronomy)|yr]] (2055 d)
 | inclination=15.94°
 | asc_node=107.6°
 | arg_peri=337.2°
 | mean_anomaly=113°
 | mean_diameter = {{val|298|4|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>
 | dimensions = (357 ± 2) × (294 ± 2) × (231 ± 50) km{{refn|name="Conrad-2007"|Conrad (2007), as cited in Baer et al. (2011).<ref name="Baer2011"/>}}{{efn|Measurements of the short axis are less precise than the other two, but also involve a discrepancy between fitting the convolved and deconvolved images ({{val|241|40|u=km}}), and fitting the edges ({{val|191|114|u=km}}).}}
 | flattening = 0.30{{efn|1=Flattening derived from the maximum aspect ratio (c/a): <math>f=1-\frac{c}{a}</math>, where (c/a) = {{val|.70|.06}}.<ref name=VLT/>}}
 | mass = {{val|26.6|7.3|e=18|u=kg}}<ref name=VLT/><br />{{val|38|2|e=18|u=kg}}{{refn|group=lower-alpha|(18.96 ± 0.99) × 10<sup>−12</sup> {{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|1.92|.53|u=g/cm3}}<ref name=VLT/><br />{{val|2.97|1.30|u=g/cm3}}<ref name=Baer2011/>
 | rotation= 0.2137 d (5.130 h)
 | spectral_type=C
 | abs_magnitude=6.43<ref name=JPL/>
 | magnitude=9.50<ref name=bright2003>
{{cite web
  |title=Bright Minor Planets 2003
  |publisher=[[Minor Planet Center]]
  |url=http://www.cfa.harvard.edu/iau/Ephemerides/Bright/2003
  |access-date=2008-05-21
  }}{{Dead link|date=April 2019 |bot=InternetArchiveBot |fix-attempted=yes }}
</ref> to 12.98
 | albedo={{val|0.076|0.007}} geometric ({{val|0.717|0.013}} BV, {{val|0.363|0.020}})<ref name=JPL/>
 | single_temperature=~160 [[kelvin|K]]
}}

'''511 Davida''' is a large C-type [[asteroid]] in the [[asteroid belt]]. It is one of the [[List of exceptional asteroids|largest asteroids]]; approximately tied for 7th place, to within measurement uncertainties, and the 5th or 6th most massive. It was discovered by [[Raymond Smith Dugan|R. S. Dugan]] in 1903. Davida is named after [[David Peck Todd]], an astronomy professor at [[Amherst College]].

== Physical characteristics ==
[[File:DavidaNGC5792-mag12.jpg|thumb|left|Asteroid 511 Davida (lower left at [[apparent magnitude|mag]] 12.5) near galaxy [[NGC 5792]]]]
[[File:511 Davida Lightcurve Inversion.png|thumb|left|3D model of Davida based on lightcurve modeling]]
[[File:Davida.jpg|thumb|left|Keck telescope image sequence of Davida showing its rotation]]
Davida is approximately 270–310&nbsp;km in [[diameter]] and comprises an estimated 1.5% of the total mass of the asteroid belt.<ref name=Baer/><ref name="Pitjeva05">{{cite journal|last=Pitjeva |first=E. V. |author-link=Elena V. Pitjeva |title=High-Precision Ephemerides of Planets—EPM and Determination of Some Astronomical Constants |journal=Solar System Research |year=2005 |volume=39 |issue=3 |pages=176 |url=http://iau-comm4.jpl.nasa.gov/EPM2004.pdf |format=[[PDF]] |doi=10.1007/s11208-005-0033-2 |bibcode=2005SoSyR..39..176P |url-status=dead |archive-url=https://web.archive.org/web/20081031065523/http://iau-comm4.jpl.nasa.gov/EPM2004.pdf |archive-date=October 31, 2008 |df=mdy }}</ref>{{efn|1="Baer Mass of 511 Davida" 0.220 / "Mass of Mbelt" 15 = 0.0146}} It is a [[C-type asteroid]], which means that it is dark in colouring with a [[carbonaceous chondrite]] composition.

From 2002 to 2007, astronomers at the [[Keck Observatory]] used the Keck II telescope, which is fitted with [[adaptive optics]], to photograph Davida. The asteroid is not a [[dwarf planet]]: there are at least two [[promontories]] and at least one flat facet with 15-km deviations from a best-fit [[ellipsoid]]. The facet is presumably a 150-km global-scale crater like the ones seen on [[253 Mathilde]]. Conrad et al. (2007) show that craters of this size "can be expected from the impactor size distribution, without likelihood of catastrophic disruption of Davida."

=== Mass ===
In 2001, Michalak estimated Davida to have a mass of {{val|6.64|0.56|e=19|u=kg}}.<ref name=Michalak2001/>{{efn|{{val|3.34|0.28|e=-11|u=solar masses}}, per Michalak (2001), extended dynamic model.}}  In 2007, Baer and Chesley estimated Davida to have a mass of {{val|5.9|0.6|e=19|u=kg}}.<ref name="Baer2007"/> {{As of|2010}}, Baer suggests Davida has a mass of {{val|3.84|0.20|e=19|u=kg}}.<ref name=Baer/> This most recent estimate by Baer indicates that Davida is approximately tied with [[704 Interamnia]] as the fifth-most-massive asteroid, though the [[error bar]]s of Interamnia are large.<ref name=Baer/>
{{clear|left}}

===Composition===
Davida's ore content is calculated to be large, and tops other asteroids in calculated worth, with [[16 Psyche]] coming second with a large difference in hypothetical worth.<ref name="a689">{{cite web | last=Gamillo | first=Elizabeth | title=This Metal-Rich, Potato-Shaped Asteroid Could Be Worth $10 Quintillion | website=Smithsonian Magazine | date=January 4, 2022 | url=https://www.smithsonianmag.com/smart-news/asteroid-16-psyche-may-be-worth-more-than-planet-earth-at-10-quintillion-in-fine-metals-180979303/ | access-date=July 8, 2025}}</ref>

== Occultations ==
There have been 9 [[occultation]] events observed since 1987, many of which produced two or three [[Chord (astronomy)|chords]].<ref>{{Cite web|url=https://sbn.psi.edu/pds-staging/resource/occ.html|title=PDS Asteroid/Dust Subnode|website=sbn.psi.edu|language=en|access-date=2018-04-27|archive-url=https://web.archive.org/web/20180425115705/https://sbn.psi.edu/pds-staging/resource/occ.html|archive-date=April 25, 2018|url-status=dead|df=mdy-all}}</ref> Two examples shown here.

{{multiple image
 |direction = horizontal
 |align     = left
 |width1    = 225
 |width2    = 225
 |width3    = 200
 |image1    = 511Davida 20160805 (DoubleChordOccultation).jpg
 |image2    = 511Davida 20090206 (TripleChordOccultation).jpg
 |footer    = [[Asteroid occultation|Occultations]] by 511 Davida: ''Left'': Double chord occultation of TYC 5597-01223 on 5 August 2016, observed by two amateur astronomers in eastern Australia. Both observers noted step events, thereby detecting the star has two components. ''Right'': Triple chord occultation of TYC 1964-00787, observed on 6 February 2009 by three astronomers in eastern United States.
}}

[[File:511Davida 20160805 (SteppedOccultationLightCurve).jpg|thumb|511 Davida occulted TYC 5597-01223 on 5 August 2016. Two observers recorded the event and both observed step events. Shown here is the step recording by Dave Herald.]]
{{clear}}

== Notes ==
{{notelist}}

== References ==
{{reflist|refs=

<ref name=Michalak2001>{{cite journal
 |last=Michalak
 |first=G.
 |title=Determination of asteroid masses (6) Hebe, (10) Hygiea, (15) Eunomia, (52) Europa, (88) Thisbe, (444) Gyptis, (511) Davida and (704) Interamnia
 |journal=Astronomy & Astrophysics
 |volume=374
 |pages=703–711
 |year=2001
 |doi=10.1051/0004-6361:20010731
 |url=http://www.aanda.org/index.php?option=article&access=standard&Itemid=129&url=/articles/aa/abs/2001/29/aa10228/aa10228.html
 |archive-url=https://archive.today/20121204183828/http://www.aanda.org/index.php?option=article&access=standard&Itemid=129&url=/articles/aa/abs/2001/29/aa10228/aa10228.html
 |url-status=dead
 |archive-date=2012-12-04
 |access-date=2008-11-04
 |bibcode=2001A&A...374..703M
|doi-access=free
 }}</ref>

<ref name="Baer2007">{{cite journal
  |last=Baer |first=James
  |author2=Steven R. Chesley
  |title=Astrometric masses of 21 asteroids, and an integrated asteroid ephemeris
  |journal=Celestial Mechanics and Dynamical Astronomy
  |volume=100 |issue=2008 |pages=27–42
  |publisher=Springer Science+Business Media B.V. 2007
  |doi=10.1007/s10569-007-9103-8
  |year=2007 |bibcode = 2008CeMDA.100...27B |quote=({{val|2.98|0.30}}){{e|−11}} [[sun|solar masses]]|doi-access=free
  }}</ref>

<ref name=Baer>
{{cite web
  |year=2010
  |title=Recent Asteroid Mass Determinations
  |publisher=Personal Website
  |first=James
  |last=Baer
  |url=http://home.earthlink.net/~jimbaer1/astmass.txt
  |access-date=2011-02-13
  |archive-url=https://web.archive.org/web/20130702212735/http://home.earthlink.net/~jimbaer1/astmass.txt
  |archive-date=July 2, 2013
  |url-status=dead
  |df=mdy-all
  }}
</ref>

<ref name="Ferret">{{cite web
  |title      = Asteroid 511 Davida – Nesvorny HCM Asteroid Families V3.0
  |work       = Small Bodies Data Ferret
  |url        = https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=511+Davida
  |access-date = 24 October 2019}}</ref>

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

== External links ==
{{Commons}}
* [https://web.archive.org/web/20140108170501/http://www.asteroidoccultation.com/observations/Results/index2011.html Asteroid occultations], IOTA – International Occultation Timing Association (2011)
* [http://physics.bgsu.edu/~layden/Anim/Asteroids/davida.htm Time lapse photography of Davida]
* [https://web.archive.org/web/20070720154543/http://www2.keck.hawaii.edu/inst/people/conrad/research/ Al Conrad's research page at Keck]
* {{AstDys|511}}
* {{JPL small body}}

{{Minor planets navigator|510 Mabella|number=511|512 Taurinensis}}
{{Small Solar System bodies}}
{{Large asteroids}}
{{Authority control}}

{{DEFAULTSORT:000511}}
[[Category:Meliboea asteroids]]
[[Category:Discoveries by Raymond Dugan|Davida]]
[[Category:Named minor planets|Davida]]
[[Category:C-type asteroids (Tholen)]]
[[Category:C-type asteroids (SMASS)]]
[[Category:1903 in science]]
[[Category:Astronomical objects discovered in 1903|19030530]]