View source for Astronomy:1981 Midas

{{Infobox planet
 | minorplanet     = yes
 | name            = 1981 Midas
 | background      = #FFC2E0
 | image           = Midas Arecibo radar 2018 Mar 23.gif
 | image_scale      =
 | caption         = Radar images of Midas by the [[Astronomy:Arecibo Observatory|Arecibo Observatory]] in March 2018
 | discovery_ref   = <ref name="jpldata" />
 | discovered      = 6 March 1973
 | discoverer      = C. Kowal
 | discovery_site  = [[Organization:Palomar Observatory|Palomar Obs.]]
 | mpc_name        = (1981) Midas
 | alt_names       = 1973 EA
 | pronounced      = {{IPAc-en|ˈ|m|ai|d|@|s}}<ref>{{Cite encyclopedia |url=http://www.lexico.com/definition/Midas |archive-url=https://web.archive.org/web/20200204154416/https://www.lexico.com/definition/midas |url-status=dead |archive-date=4 February 2020 |title=Midas |dictionary=Lexico UK English Dictionary |publisher=[[Organization:Oxford University Press|Oxford University Press]]}}</ref>
 | named_after     = [[Chemistry:Midas|Midās]] {{small|(Greek mythology)}}<ref name="springer" />
 | mp_category     = {{Hlist
  | [[Astronomy:Apollo asteroid|Apollo]]
  | [[Astronomy:Near-Earth object|NEO]]
  | [[Astronomy:Potentially hazardous asteroid|PHA]]<ref name="jpldata"/><ref name="MPC-Midas" />
  | Venus-crosser
  | [[Astronomy:Mars-crosser|Mars-crosser]]
  }}
 | orbit_ref       = <ref name="jpldata" />
 | epoch           = 4 September 2017 ([[Astronomy:Julian day|JD]]&nbsp;2458000.5)
 | uncertainty     = 0
 | observation_arc = 41.97&nbsp;yr (15,330 days)
 | aphelion        = 2.9307&nbsp;[[Astronomy:Astronomical unit|AU]]
 | perihelion      = 0.6212&nbsp;AU
 | semimajor       = 1.7759&nbsp;AU
 | eccentricity    = 0.6502
 | period          = 2.37&nbsp;[[Astronomy:Julian year|yr]] (864 days)
 | mean_anomaly    = 256.48[[Degree (angle)|°]]
 | mean_motion     = {{Deg2DMS|0.4165|sup=ms}} / day
 | inclination     = 39.833°
 | asc_node        = 356.90°
 | arg_peri        = 267.80°
 | moid            = 0.0045&nbsp;AU (1.8&nbsp;[[Astronomy:Lunar distance|LD]])
 | dimensions      = {{Ubl
  | {{val|1.95|0.07|u=km}}<ref name="AKARI" /><ref name="lcdb" />
  | 3.4&nbsp;km {{small|(outdated)}}<ref name="jpldata" />
  }}
 | rotation        = {{val|5.22|u=h}}<ref name="Mottola-1995a" /><ref name="Torppa-2005" />
 | albedo          = {{Ubl
  | 0.2661 {{small|(derived)}}<ref name="lcdb" />
  | {{val|0.293|0.025}}<ref name="AKARI" />
  }}
 | spectral_type   = {{Hlist
  | SMASS {{=}} V<ref name="jpldata" />
  | [[Astronomy:V-type asteroid|V]]<ref name="lcdb" />
  }}
 | abs_magnitude   = {{Ubl
  | 15.18<ref name="Mottola-1995a" />
  | 15.2<ref name="jpldata" />
  | 15.50<ref name="AKARI" />
  | {{val|15.6|0.2}}<ref name="lcdb" /><ref name="Wisniewski-1997" /><ref name="Pravec-2012b" />
  | {{val|15.96|0.23}}<ref name="Veres-2015" />
  }}
}}

'''1981 Midas''', provisional designation {{mp|1973 EA}}, is a vestoid [[Astronomy:Asteroid|asteroid]], classified as a [[Astronomy:Near-Earth object|near-Earth object]] and [[Astronomy:Potentially hazardous asteroid|potentially hazardous asteroid]], approximately 2 kilometers in diameter.<ref name="jpldata"/>

It was discovered on 6 March 1973 by American astronomer Charles Kowal at [[Organization:Palomar Observatory|Palomar Observatory]] in San Diego County, California.<ref name="MPC-Midas" /> It was named after King [[Chemistry:Midas|Midas]] from Greek mythology.<ref name="springer" />

== Classification and orbit ==

The moderately bright [[Astronomy:V-type asteroid|V-type asteroid]] is also an [[Astronomy:Apollo asteroid|Apollo asteroid]], as well as a Venus and Mars-crosser. The asteroid orbits the Sun at a distance of 0.6–2.9&nbsp;[[Astronomy:Astronomical unit|AU]] once every 2 years and 4 months (864 days). Its orbit has an [[Astronomy:Orbital eccentricity|eccentricity]] of 0.65 and an [[Astronomy:Orbital inclination|inclination]] of 40[[Degree (angle)|°]] with respect to the [[Astronomy:Ecliptic|ecliptic]].<ref name="jpldata"/>

''Midas'' has a low [[Astronomy:Minimum orbit intersection distance|minimum orbit intersection distance]] with Earth of {{convert|0.0036|AU|km mi|abbr=on|lk=off}}, which corresponds to 1.5 lunar distance (Earth–Moon distance). However, it does not pose an impact risk for the foreseeable future. On 19 March 1947 it passed {{convert|0.0298|AU|km mi|abbr=on|lk=on}} from Earth.<ref name=jpl-close/> The last notable close approach was on 21 March 2018 passing {{convert|0.08957|AU|km mi|abbr=on|lk=off}} from Earth<ref name=jpl-close/> and shining at an [[Astronomy:Apparent magnitude|apparent magnitude]] of +12.4.<ref name="NEODyS2018"/> The next notable close approach will be on 14 September 2032 passing slightly closer at {{convert|0.08635|AU|km mi|abbr=on|lk=off}} from Earth.<ref name=jpl-close/> As no precoveries are known, the asteroid's [[Astronomy:Observation arc|observation arc]] begins with its discovery observation at Palomar in 1973.<ref name="MPC-Midas" />

With a semi-major axis of 1.78 AU, when 1 AU from the Sun (and passing Earth's orbit) the asteroid is moving at 35.7&nbsp;km/s with respect to the Sun.{{efn|name=speed}} For comparison [[Astronomy:Orbital speed#Planets|Earth orbits the Sun at 30 km/s.]]

== Physical characteristics ==

Three rotational [[Astronomy:Lightcurve|lightcurve]]s obtained from photometric observations gave a concurring [[Rotation period|rotation period]] of 5.24 hours with a relatively high brightness variation of 0.65, 0.8 and 0.87 in [[Astronomy:Magnitude|magnitude]], respectively ({{small|U=3/2/3}}).<ref name="Torppa-2005" /><ref name="Mottola-1995a" /><ref name="Wisniewski-1997" />

According to the survey carried out by the Japanese [[Astronomy:Akari (satellite)|Akari]] satellite, ''Midas'' measures 1.95 kilometers in diameter and its surface has an [[Astronomy:Astronomical albedo|albedo]] of 0.293,<ref name="AKARI" /> while the ''Collaborative Asteroid Lightcurve Link'' assumes an albedo of 0.266 and calculates an identical diameter of 1.95 kilometers with an [[Astronomy:Absolute magnitude|absolute magnitude]] of 15.6.<ref name="lcdb" />

In 1987, ''Midas'' was also detected by radar from [[Astronomy:Goldstone Deep Space Communications Complex|Goldstone Deep Space Communications Complex]] at a distance of 0.08&nbsp;[[Astronomy:Astronomical unit|AU]] with a measured maximal [[Physics:Radar cross-section|radar cross-section]] of 0.1&nbsp;km<sup>2</sup>.<ref name="Ostro1991" />

== Naming ==

This [[Astronomy:Minor planet|minor planet]] was named after the figure from Greek mythology, [[Chemistry:Midas|Midas]], the King of [[History:Phrygia|Phrygia]], who turned whatever he touched to gold. He received this ability as an award, but soon realized that this gift was a curse when his daughter turned into a statue after he had touched her. Relieved of his power by bathing in the river Pactolus, other accounts also tell his death caused by starvation.<ref name="springer" /> The official {{MoMP|1981|naming citation}} was published by the [[Organization:Minor Planet Center|Minor Planet Center]] on 15 October 1977 ({{small|M.P.C. 4237}}).<ref name="DoMP-Circular-dates" />

== Notes ==
{{notelist|refs=

{{efn|name=speed|{{nowrap|1=''v'' = 42.1219 {{radic|1/''r'' − 0.5/''a''}}}}, where ''r'' is the distance from the Sun, and ''a'' is the major semi-axis. Objects move fastest at [[Astronomy:Apsis#Perihelion and aphelion|perihelion]] and slowest at aphelion.}}

}} <!-- end of notelist -->

== References ==
{{reflist|30em|refs=

<ref name="Ostro1991">{{cite journal
  |display-authors = 4
  |last1     = Ostro |first1    = S. J.
  |last2     = Jurgens |first2    = R. F.
  |last3     = Rosema |first3    = K. D.
  |last4     = Winkler |first4    = R.
  |last5     = Yeomans |first5    = D. K.
  |last6     = Campbell |first6    = D. B.
  |last7     = Chandler |first7    = J. F.
  |last8     = Shapiro |first8    = I. I.
  |last9     = Hine |first9    = A. A.
  |last10    = Velez |first10   = R.
  |title     = Asteroid radar astrometry
  |journal      = Astronomical Journal
  |volume    = 102
  |pages     = 1490–1502
  |date      = October 1991
  |bibcode   = 1991AJ....102.1490O
  |doi       = 10.1086/115975}}</ref>

<ref name="jpldata">{{cite web
  |type       = 2015-02-24 last obs.
  |title      = JPL Small-Body Database Browser: 1981 Midas (1973 EA)
  |url        = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2001981
  |publisher  = [[Organization:Jet Propulsion Laboratory|Jet Propulsion Laboratory]]
  |accessdate = 1 July 2017}}</ref>

<ref name="springer">{{cite book
  |title      = Dictionary of Minor Planet Names – (1981) Midas
  |last       = Schmadel | first = Lutz D.
  |publisher  = Springer Berlin Heidelberg
  |page       = 160
  |date       = 2007
  |isbn       = 978-3-540-00238-3
  |doi       = 10.1007/978-3-540-29925-7_1982 |chapter       = (1981) Midas }}</ref>

<ref name="MPC-Midas">{{cite web
  |title      = 1981 Midas (1973 EA)
  |work       = Minor Planet Center
  |url        = https://www.minorplanetcenter.net/db_search/show_object?object_id=1981
  |accessdate = 18 September 2016}}</ref>

<ref name="DoMP-Circular-dates">{{cite book
  |title      = Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008)
  |year      = 2009
  |url      = https://archive.org/details/dictionaryminorp2008schm
  |url-access = limited
  |chapter    = Appendix{{Snd}} Publication Dates of the MPCs
  |last       = Schmadel |first=Lutz D.
  |publisher  = Springer Berlin Heidelberg
  |page       = [https://archive.org/details/dictionaryminorp2008schm/page/n230 221]
  |isbn       = 978-3-642-01964-7
  |doi        = 10.1007/978-3-642-01965-4}}</ref>

<ref name=jpl-close>{{cite web
  |type       = 2013-12-30 last obs
  |title      = JPL Close-Approach Data: 1981 Midas (1973 EA)
  |url        = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Midas;cad=1#cad
  |archive-url = https://web.archive.org/web/20200828175338/https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=Midas;cad=1#cad
  |url-status = dead
  |archive-date = 2020-08-28
  |accessdate = 2014-01-31}}</ref>

<ref name="NEODyS2018">{{cite web
  |title      = (1981) Midas Ephemerides for 15 Feb 2018 through 15 Apr 2018
  |publisher  = [[Astronomy:NEODyS|NEODyS]] (Near Earth Objects{{Snd}} Dynamic Site)
  |url        = https://newton.spacedys.com/neodys/index.php?pc=1.1.3.1&n=1981&oc=500&y0=2018&m0=2&d0=15&h0=0&mi0=0&y1=2018&m1=4&d1=15&h1=0&mi1=0&ti=1.0&tiu=days
  |accessdate = 2014-01-31}}</ref>
 
<ref name="lcdb">{{cite web
  |title      = LCDB Data for (1981) Midas
  |publisher  = Asteroid Lightcurve Database (LCDB)
  |url        = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=1981%7CMidas
  |accessdate = 18 September 2016}}</ref>

<ref name="AKARI">{{cite journal
  |display-authors = 6
  |first1     = Fumihiko |last1 = Usui
  |first2     = Daisuke |last2 = Kuroda
  |first3     = Thomas G. |last3 = Müller
  |first4     = Sunao |last4 = Hasegawa
  |first5     = Masateru |last5 = Ishiguro
  |first6     = Takafumi |last6 = Ootsubo
  |first7     = Daisuke |last7 = Ishihara
  |first8     = Hirokazu |last8 = Kataza
  |first9     = Satoshi |last9 = Takita
  |first10    = Shinki |last10 = Oyabu
  |first11    = Munetaka |last11 = Ueno
  |first12    = Hideo |last12 = Matsuhara
  |first13    = Takashi |last13 = Onaka
  |date       = October 2011
  |title      = Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey
  |journal    = Publications of the Astronomical Society of Japan
  |volume     = 63
  |issue      = 5
  |pages      = 1117–1138
  |bibcode    = 2011PASJ...63.1117U
  |doi        = 10.1093/pasj/63.5.1117
  |doi-access= 
  }} ([http://vizier.cfa.harvard.edu/viz-bin/VizieR-5?-source=J/PASJ/63/1117/acua_v1&Num=1981 online], [https://core.ac.uk/download/pdf/43545172.pdf AcuA catalog p. 153])</ref>

<ref name="Mottola-1995a">{{cite journal
  |author     = Mottola, S.
  |author2    = de Angelis, G.
  |author3    = di Martino, M.
  |author4    = Erikson, A.
  |author5    = Harris, A. W.
  |author6    = Hahn, G.
  |author7    = Neukum, G.
  |author8    = Pravec, P.
  |author9    = Wolf, M.
  |date       = March 1995
  |title      = The EUNEASO Photometric Follow-up Program
  |journal    = Abstracts of the Lunar and Planetary Science Conference
  |volume    = 26
  |pages    = 1003
  |bibcode    = 1995LPI....26.1003M}}</ref>

<ref name="Wisniewski-1997">{{cite journal
  |author     = Wisniewski, W. Z.
  |author2    = Michalowski, T. M.
  |author3    = Harris, A. W.
  |author4    = McMillan, R. S.
  |date       = March 1995
  |title      = Photoelectric Observations of 125 Asteroids
  |journal    = Abstracts of the Lunar and Planetary Science Conference
  |volume    = 26
  |pages    = 1511
  |bibcode    = 1995LPI....26.1511W}}</ref>

<ref name="Torppa-2005">{{cite journal
  |display-authors    = 8
  |author     = Torppa, J.
  |author2    = Aksnes, K.
  |author3    = Dai, Z.
  |author4    = Grav, T.
  |author5    = Hahn, G.
  |author6    = Laakso, T.
  |author7    = Lagerkvist, C.-I.
  |author8    = Muinonen, K.
  |author9    = Niemelaa, J.
  |author10   = Naaraanen, J.
  |author11   = Rickman, H.
  |author12   = Virtanen, J.
  |date       = August 2005
  |title      = Spins and Shapes of Potentially Hazardous Asteroids
  |journal    = American Astronomical Society
  |volume     = 37
  |page       = 643
  |bibcode    = 2005DPS....37.1526T}}</ref>

<ref name="Pravec-2012b">{{cite journal
  |author     = Pravec, Petr
  |author2    = Harris, Alan W.
  |author3    = Kusnirák, Peter
  |author4    = Galád, Adrián
  |author5    = Hornoch, Kamil
  |date       = September 2012
  |title      = Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations
  |journal    = Icarus
  |volume     = 221
  |issue      = 1
  |pages      = 365–387
  |bibcode    = 2012Icar..221..365P
  |doi        = 10.1016/j.icarus.2012.07.026}}</ref>

<ref name="Veres-2015">{{cite journal
  |display-authors = 6
  |first1     = Peter |last1 = Veres
  |first2     = Robert |last2 = Jedicke
  |first3     = Alan |last3 = Fitzsimmons
  |first4     = Larry |last4 = Denneau
  |first5     = Mikael |last5 = Granvik
  |first6     = Bryce |last6 = Bolin
  |first7     = Serge |last7 = Chastel
  |first8     = Richard J. |last8 = Wainscoat
  |first9     = William S. |last9 = Burgett
  |first10    = Kenneth C. |last10 = Chambers
  |first11    = Heather |last11 = Flewelling
  |first12    = Nick |last12 = Kaiser
  |first13    = Eugen A. |last13 = Magnier
  |first14    = Jeff S. |last14 = Morgan
  |first15    = Paul A. |last15 = Price
  |first16    = John L. |last16 = Tonry
  |first17    = Christopher |last17 = Waters
  |date       = November 2015
  |title      = Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1{{Snd}} Preliminary results
  |journal    = Icarus
  |volume     = 261
  |pages      = 34–47
  |bibcode    = 2015Icar..261...34V
  |doi        = 10.1016/j.icarus.2015.08.007
  |arxiv      = 1506.00762}}</ref>

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

== External links ==
* [http://www.cbat.eps.harvard.edu/iauc/02800/02816.html#Item2 IAUC 2816] (13 August 1975){{Snd}} [http://www.cbat.eps.harvard.edu/iauc/02800/02890.html#Item3 IAUC 2890] (29 December 1975){{Snd}} [http://www.cbat.eps.harvard.edu/iauc/02900/02979.html#Item2 IAUC 2979] (26 July 1976)
* [https://newton.spacedys.com/neodys/index.php?pc=1.1.8&n=1981 NeoDys] Close Approaches from 1950 to 2100
* [https://books.google.com/books?id=aeAg1X7afOoC&pg Dictionary of Minor Planet Names], Google books
* [http://www.minorplanet.info/PHP/lcdbsummaryquery.php Asteroid Lightcurve Database (LCDB)], query form ([http://www.minorplanet.info/lightcurvedatabase.html info] {{Webarchive|url=https://web.archive.org/web/20171216050541/http://www.minorplanet.info/lightcurvedatabase.html |date=16 December 2017 }})
* [http://obswww.unige.ch/~behrend/page_cou.html Asteroids and comets rotation curves, CdR]{{Snd}} Observatoire de Genève, Raoul Behrend
* [https://www.youtube.com/watch?v=W3nU_6XEsck&t=278 Asteroid Hazards, Part 1: What Makes an Asteroid a Hazard?]{{Snd}} [[Organization:Minor Planet Center|Minor Planet Center]] on YouTube
* {{NeoDys|1981}}
* {{ESA-SSA|1981|Midas}}
* {{JPL small body}}

{{Small Solar System bodies}}

{{DEFAULTSORT:Midas}}
[[Category:Apollo asteroids|001981]]
[[Category:Named minor planets]]
[[Category:Potentially hazardous asteroids|001981]]
[[Category:Radar-imaged asteroids|001981]]
[[Category:V-type asteroids|001981]]

{{Sourceattribution|1981 Midas}}