{{Short description|Asteroid}} {{Use dmy dates|date=October 2019}} {{Infobox planet | minorplanet = yes | name = 9950 ESA | background = #FFC2E0 | image = AnimatedOrbitOf9950ESA.gif | image_size = | caption = Animated orbit of 9950 ESA | discovery_ref = <ref name="jpldata" /> | discoverer = C. Pollas | discovery_site = Caussols Obs. {{small|(010)}} | discovered = 8 November 1990 | mpc_name = (9950) ESA | alt_names = 1990 VB | pronounced = | named_after = {{nowrap|European Space Agency<ref name="springer" />}} | mp_category = NEO{{·}}Amor<ref name="jpldata" /><ref name="MPC-object" /><ref name="Harris-1991" /><br />Mars-crosser | orbit_ref = <ref name="jpldata" /> | epoch = 4 September 2017 (JD 2458000.5) | uncertainty = 0 | observation_arc = 26.90 yr (9,824 days) | aphelion = 3.7367 AU | perihelion = 1.1391 AU | semimajor = 2.4379 AU | eccentricity = 0.5328 | period = 3.81 yr (1,390 days) | mean_anomaly = 17.795° | mean_motion = {{Deg2DMS|0.2589|sup=ms}} / day | inclination = 14.597° | asc_node = 253.51° | arg_peri = 103.57° | moid = 0.2806 AU{{·}}109.3 LD | dimensions = 1.71 km {{small|(calculated)}}<ref name="lcdb" /><br />3 km {{small|(estimated)}}<ref name="Harris-1991" />{{rp|21}} | rotation = {{val|6.707|0.002}} h<ref name="Stephens-2014d" />{{efn|name=lightcurve-plot-Stephens}}<br />{{val|6.7078|0.0007}} h<ref name="Vaduvescu-2017" /><br />{{val|6.712|0.005}} h<ref name="Warner-2014b" />{{efn|name=lightcurve-plot-Warner}} | albedo = 0.20 {{small|(assumed)}}<ref name="lcdb" /> | spectral_type = S {{small|(assumed)}}<ref name="lcdb" /> | abs_magnitude = 16.2<ref name="jpldata" /><ref name="lcdb" /> }}
'''9950 ESA''', provisional designation {{mp|1990 VB}}, is an eccentric asteroid and elongated near-Earth object of the Amor group, approximately 1.7 kilometers in diameter. It was discovered on 8 November 1990, by French astronomer Christian Pollas at the Centre de recherches en géodynamique et astrométrie (Cerga) at Caussols in southeastern France.<ref name="MPC-object" /> It was named for the European Space Agency (ESA).<ref name="springer" />
== Orbit and classification == ''ESA'' is an Amor asteroid – a subgroup of near-Earth asteroids that approach the orbit of Earth from beyond, but do not cross it. It orbits the Sun at a distance of 1.1–3.7 AU once every 3 years and 10 months (1,390 days). Its orbit has an eccentricity of 0.53 and an inclination of 15° with respect to the ecliptic.<ref name="jpldata" /> The body's observation arc begins with its official discovery observation at Caussols in November 1990.<ref name="MPC-object" />
=== Close approaches ===
''ESA'' has an Earth minimum orbit intersection distance of {{convert |0.2806 |AU |km |abbr=on |sigfig=3}}, which corresponds to 109.3 lunar distances. It approached the Earth at 0.393 AU on 18 October 1990, three weeks prior to its discovery, and made two more close approaches in August and September 2013, respectively. Its next close encounter with Earth will be in October 2032, at distance of {{convert |0.3043 |AU |km |abbr=on |sigfig=3}}.<ref name="jpldata" />
The eccentric asteroid is also a Mars-crosser. In March 1987, it approached the Red Planet at {{convert |0.0990 |AU |km |abbr=on |sigfig=3}}.<ref name="jpldata" />
== Physical characteristics ==
''ESA'' is an assumed stony S-type asteroid.<ref name="lcdb" />
=== Rotation period ===
In 2013, three rotational lightcurves of ''ESA'' were obtained from photometric observations by the EURONEAR Lightcurve Survey and by American astronomers Brian Warner and Robert Stephens at the Center for Solar System Studies ({{small|U81/U82}}). Lightcurve analysis gave a rotation period between 6.707 and 6.712 hours with a brightness variation of 0.44 to 0.89 magnitude ({{small|U=3/3/3-}}).<ref name="Stephens-2014d" /><ref name="Vaduvescu-2017" /><ref name="Warner-2014b" />{{efn|name=lightcurve-plot-Stephens}}{{efn|name=lightcurve-plot-Warner}} A high brightness amplitude typically indicates that the body's shape is irregular and elongated, rather than spherical.
=== Diameter and albedo ===
In the early 1990s, David Tholen at the Institute for Astronomy of the University of Hawaii estimated a diameter of 3 kilometers for ''ESA''.<ref name="Harris-1991" />{{rp|21}} The ''Collaborative Asteroid Lightcurve Link'' assumes a standard albedo for stony asteroids of 0.20 and calculates a diameter of 1.71 kilometers based on an absolute magnitude of 16.2.<ref name="lcdb" />
== Naming ==
This minor planet was named after the European Space Agency (ESA), which formed in 1974. The name was suggested by French astronomer Jean Louis Heudier, after whom the asteroid 4602 Heudier was named.<ref name="springer" /> The official naming citation was published by the Minor Planet Center on 15 December 2005 ({{small|M.P.C. 55720}}).<ref name="MPC-Circulars-Archive" />
== Notes == {{notelist|refs=
{{efn|name=lightcurve-plot-Warner|1=Warner (2013) [http://www.planetarysciences.org/plots/BDW/9950_ESA_2013-08-05.PNG lightcurve plot of (9950) ESA] rotation period {{val|6.712|0.005}} hours with a brightness amplitude of {{val|0.56|0.03}} mag. Quality code: 3. Summary figures at the [http://planetarysciences.org/ Center for Solar System Studies] and at the [http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=9950%7CESA LCDB]}}
{{efn|name=lightcurve-plot-Stephens|1=Stephens (2013) [http://www.planetarysciences.org/plots/RDS/9950_ESA_2013-11-25.PNG lightcurve plot of (9950) ESA] rotation period {{val|6.707|0.002}} hours with a brightness amplitude of {{val|0.44|0.02}} mag. Quality code: 3. Summary figures at the [http://planetarysciences.org/ Center for Solar System Studies] and at the [http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=9950%7CESA LCDB]}}
}} <!-- end of notelist -->
== References == {{reflist|30em|refs=
<ref name="jpldata">{{cite web |type = 2017-10-01 last obs. |title = JPL Small-Body Database Browser: 9950 ESA (1990 VB) |url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2009950 |publisher = Jet Propulsion Laboratory |access-date = 6 October 2017}}</ref>
<ref name="springer">{{cite book |title = Dictionary of Minor Planet Names – (9950) ESA, Addendum to Fifth Edition: 2003–2005 |last = Schmadel | first = Lutz D. |publisher = Springer Berlin Heidelberg |page = 49 |date = 2006 |isbn = 978-3-540-34361-5 |doi = 10.1007/978-3-540-34361-5_388 |chapter = (9950) Esa [2.44, 0.53, 14.6] }}</ref>
<ref name="MPC-object">{{cite web |title = 9950 ESA (1990 VB) |work = Minor Planet Center |url = https://www.minorplanetcenter.net/db_search/show_object?object_id=9950 |access-date = 6 October 2017}}</ref>
<ref name="MPC-Circulars-Archive">{{cite web |title = MPC/MPO/MPS Archive |work = Minor Planet Center |url = https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html |access-date = 6 October 2017}}</ref>
<ref name="Harris-1991">{{Cite journal |first1 = A. W. |last1 = Harris |first2 = V. |last2 = Zappalá |date = June 1991 |title = Photoelectric Photometry Opportunities: May–July |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=1991MPBu...18...20H |journal = The Minor Planet Bulletin |volume = 18 |page = 20 |bibcode = 1991MPBu...18...20H |access-date= 6 October 2017}}</ref>
<ref name="lcdb">{{cite LCDB|number = 9950 |access-date = 6 October 2017}}</ref>
<ref name="Warner-2014b">{{Cite journal |author = Warner, Brian D. |date = January 2014 |title = Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2013 June–September |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2014MPBu...41...41W |journal = The Minor Planet Bulletin |volume = 41 |issue = 1 |pages = 41–47 |pmid = 32457957 |pmc = 7249616 |issn = 1052-8091 |bibcode = 2014MPBu...41...41W |access-date= 6 October 2017}}</ref>
<ref name="Stephens-2014d">{{Cite journal |author = Stephens, Robert D. |date = April 2014 |title = Asteroids Observed from CS3: 2013 October–December |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2014MPBu...41...92S |journal = The Minor Planet Bulletin |volume = 41 |issue = 2 |pages = 92–95 |issn = 1052-8091 |bibcode = 2014MPBu...41...92S |access-date= 6 October 2017}}</ref>
<ref name="Vaduvescu-2017">{{Cite journal |display-authors = 6 |first1 = O. |last1 = Vaduvescu |first2 = A. Aznar |last2 = Macias |first3 = V. |last3 = Tudor |first4 = M. |last4 = Predatu |first5 = A. |last5 = Galád |first6 = S. |last6 = Gajdos |first7 = J. |last7 = Világi |first8 = H. F. |last8 = Stevance |first9 = R. |last9 = Errmann |first10 = E. |last10 = Unda-Sanzana |first11 = F. |last11 = Char |first12 = N. |last12 = Peixinho |first13 = M. |last13 = Popescu |first14 = A. |last14 = Sonka |first15 = R. |last15 = Cornea |first16 = O. |last16 = Suciu |first17 = R. |last17 = Toma |first18 = P. |last18 = Santos-Sanz |first19 = A. |last19 = Sota |first20 = J. |last20 = Licandro |first21 = M. |last21 = Serra-Ricart |first22 = D. |last22 = Morate |first23 = T. |last23 = Mocnik |first24 = M. Diaz |last24 = Alfaro |first25 = F. |last25 = Lopez-Martinez |first26 = J. |last26 = McCormac |first27 = N. |last27 = Humphries |date = August 2017 |title = The EURONEAR Lightcurve Survey of Near Earth Asteroids |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2017EM&P..120...41V |journal = Earth |volume = 120 |issue = 2 |pages = 41–100 |bibcode = 2017EM&P..120...41V |doi = 10.1007/s11038-017-9506-9 |access-date= 6 October 2017|hdl = 10316/80202 |s2cid = 235516956 |hdl-access= free }}</ref>
}} <!-- end of reflist -->
== External links == * [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 }}) * [https://books.google.com/books?id=aeAg1X7afOoC&pg Dictionary of Minor Planet Names], Google books * [http://obswww.unige.ch/~behrend/page_cou.html Asteroids and comets rotation curves, CdR] – Observatoire de Genève, Raoul Behrend * {{NeoDys|9950}} * {{ESA-SSA|9950|ESA}} * {{JPL small body}}
{{Minor planets navigator |9949 Brontosaurus |number=9950 |9951 Tyrannosaurus}} {{Small Solar System bodies}} {{Authority control}}
{{DEFAULTSORT:ESA}} 009950 Category:Discoveries by Christian Pollas Category:Named minor planets 19901108