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161989 Cacus

{{Short description|Near-Earth asteroid in 1941/2022}}

{{Use dmy dates|date=October 2019}}

{{Infobox planet

| minorplanet = yes

| name = 161989 Cacus

| background = #FFC2E0

| image = 161989-asteroid shape model (161989) Cacus.png

| image_scale =

| caption = Shape model of Cacus from its lightcurve

| discovery_ref =

| discoverer = H.-E. Schuster

| discovery_site = La Silla Obs.

| discovered = 8 February 1978

| mpc_name = (161989) Cacus

| alt_names = 1978 CA

| pronounced =

| named_after = Cacus {{small|(Roman mythology)}}

| mp_category = Apollo{{·}}NEO{{·}}PHA

| orbit_ref =

| epoch = 4 September 2017 (JD 2458000.5)

| uncertainty = 0

| observation_arc = 38.59 yr (14,096 days)

| aphelion = 1.3634 AU

| perihelion = 0.8828 AU

| semimajor = 1.1231 AU

| eccentricity = 0.2140

| period = 1.19 yr (435 days)

| mean_anomaly = 345.40°

| mean_motion = {{Deg2DMS|0.8281|sup=ms}} / day

| inclination = 26.060°

| asc_node = 161.24°

| arg_peri = 102.16°

| moid = 0.0152 AU{{·}}5.9 LD

| mean_diameter = {{val|0.64|0.02|ul=km}}
{{val|1.126|0.073}} km
{{val|1.86}} km
{{val|1.9}} km

| rotation = {{val|3.7538|0.0019|ul=h}}
{{val|3.756|}} h
{{val|3.761|}} h
{{val|3.77|0.11}} h

| albedo = {{val|0.09}}
0.119 {{small|(derived)}}
{{val|0.199|0.052}}
{{val|0.46|0.09}}

| spectral_type = Tholen {{=}} S{{·}}Q
B–V {{=}} 0.910
U–B {{=}} 0.484

| abs_magnitude = 16.58{{·}}17.1{{·}}17.2{{·}}17.32{{·}}17.43

}}

161989 Cacus (prov. designation: {{mp|1978 CA}}) is a stony asteroid, classified as near-Earth object and a potentially hazardous asteroid of the Apollo group, approximately 1 kilometer in diameter. It was discovered on 8 February 1978, by German astronomer Hans-Emil Schuster at ESO's La Silla Observatory in northern Chile. Its orbit is confined between Venus and Mars.

This minor planet was named from Roman mythology, after Cacus, a fire-breathing monster, which was killed by Hercules. The official naming citation was published by the Minor Planet Center on 24 November 2007 ({{small|M.P.C. 61270}}).

class="wikitable" style="text-align:center; font-size: 0.9em;"

|+Close approaches

! Date

! JPL SBDB
nominal geocentric
distance

! uncertainty
region
(3-sigma)

bgcolor=#c2c2c2

|1941-09-02

{{val|2418754|u=km}}± 6 km
2022-09-01{{val|8607710|u=km}}± 21 km

References

{{reflist|30em|refs=

{{cite web

|type = 2016-09-12 last obs.

|title = JPL Small-Body Database Browser: 161989 Cacus (1978 CA)

|url = https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=2161989&view=OPC

|archive-url = https://web.archive.org/web/20201122210719/https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2161989

|url-status = live

|archive-date = 22 November 2020

|publisher = Jet Propulsion Laboratory

|accessdate = 13 January 2018}}

{{cite web

|title = 161989 Cacus (1978 CA)

|work = Minor Planet Center

|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=161989

|accessdate = 13 January 2018}}

{{cite web

|title = MPC/MPO/MPS Archive

|work = Minor Planet Center

|url = https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html

|accessdate = 13 January 2018}}

{{cite web

|title = LCDB Data for (161989) Cacus

|publisher = Asteroid Lightcurve Database (LCDB)

|url = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=161989%7CCacus

|accessdate = 13 January 2018}}

{{cite journal

|display-authors = 6

|first1 = A. |last1 = Mainzer

|first2 = T. |last2 = Grav

|first3 = J. |last3 = Masiero

|first4 = E. |last4 = Hand

|first5 = J. |last5 = Bauer

|first6 = D. |last6 = Tholen

|first7 = R. S. |last7 = McMillan

|first8 = T. |last8 = Spahr

|first9 = R. M. |last9 = Cutri

|first10 = E. |last10 = Wright

|first11 = J. |last11 = Watkins

|first12 = W. |last12 = Mo

|first13 = C. |last13 = Maleszewski

|date = November 2011

|title = NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results

|journal = The Astrophysical Journal

|volume = 741

|issue = 2

|page = 25

|bibcode = 2011ApJ...741...90M

|doi = 10.1088/0004-637X/741/2/90

|arxiv = 1109.6407

|s2cid = 35447010 }}

{{cite journal

|display-authors = 6

|first1 = C. R. |last1 = Nugent

|first2 = A. |last2 = Mainzer

|first3 = J. |last3 = Bauer

|first4 = R. M. |last4 = Cutri

|first5 = E. A. |last5 = Kramer

|first6 = T. |last6 = Grav

|first7 = J. |last7 = Masiero

|first8 = S. |last8 = Sonnett

|first9 = E. L. |last9 = Wright

|date = September 2016

|title = NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos

|journal = The Astronomical Journal

|volume = 152

|issue = 3

|page = 12

|bibcode = 2016AJ....152...63N

|doi = 10.3847/0004-6256/152/3/63

|arxiv = 1606.08923

|doi-access = free }}

{{Cite journal

|first1 = J. |last1 = Degewij

|first2 = L. |last2 = Lebofsky

|first3 = M. |last3 = Lebofsky

|date = March 1978

|title = 1978 CA and 1978 DA

|url = http://www.cbat.eps.harvard.edu/iauc/03100/03193.html#Item1

|journal = IAU Circ.

|volume = 3193

|issue = 3193

|pages = 1

|bibcode = 1978IAUC.3193....1D

|access-date= 13 January 2018}}

{{Cite journal

|display-authors = 6

|first1 = Bruce W. |last1 = Koehn

|first2 = Edward G. |last2 = Bowell

|first3 = Brian A. |last3 = Skiff

|first4 = Jason J. |last4 = Sanborn

|first5 = Kyle P. |last5 = McLelland

|first6 = Petr |last6 = Pravec

|first7 = Brian D. |last7 = Warner

|date = October 2014

|title = Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS) - 2009 January through 2009 June

|journal = The Minor Planet Bulletin

|volume = 41

|issue = 4

|pages = 286–300

|issn = 1052-8091

|bibcode = 2014MPBu...41..286K

}}

{{Cite journal

|first1 = H. E. |last1 = Schuster

|first2 = A. |last2 = Surdej

|first3 = J. |last3 = Surdej

|date = September 1979

|title = Photoelectric observations of two unusual asteroids - 1978 CA and 1978 DA

|journal = Astronomy and Astrophysics Supplement Series

|volume = 37

|pages = 483–486

|bibcode = 1979A&AS...37..483S

}}

{{cite journal

|first1 = Cristina A. |last1 = Thomas

|first2 = Joshua P. |last2 = Emery

|first3 = David E. |last3 = Trilling

|first4 = Marco |last4 = Delbó

|first5 = Joseph L. |last5 = Hora

|first6 = Michael |last6 = Mueller

|date = January 2014

|title = Physical characterization of Warm Spitzer-observed near-Earth objects

|journal = Icarus

|volume = 228

|pages = 217–246

|bibcode = 2014Icar..228..217T

|doi = 10.1016/j.icarus.2013.10.004

|arxiv = 1310.2000

}}

{{cite web

|title=Horizons Batch for 2022-Sep-01 06:54 UT

|publisher=JPL Horizons

|url=https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27Cacus%27&START_TIME=%272022-Sep-01%2006:54%27&STOP_TIME=%272022-Sep-02%27&STEP_SIZE=%271+day%27&QUANTITIES=%2720,39%27

|archive-url=https://web.archive.org/web/20220117020609/https://ssd.jpl.nasa.gov/horizons_batch.cgi?batch=1&COMMAND=%27Cacus%27&START_TIME=%272022-Sep-01+06%3A54%27&STOP_TIME=%272022-Sep-02%27&STEP_SIZE=%271+day%27&QUANTITIES=%2720%2C39%27

|archive-date=2022-01-17

|url-status=live

|accessdate=2022-01-17}}

}}

External links

  • [http://www.minorplanet.info/PHP/OneAsteroidInfo.php Lightcurve Database Query] (LCDB), at www.minorplanet.info
  • [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] – Geneva Observatory, Raoul Behrend
  • {{NeoDys|161989}}
  • {{ESA-SSA|161989|Cacus}}
  • {{JPL small body}}

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161989

Category:Discoveries by Hans-Emil Schuster

Category:Named minor planets

161989

161989

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