1627 Ivar
{{Short description|Elongated stony asteroid and near-Earth object}}
{{Use dmy dates|date=October 2019}}
{{Infobox planet
| minorplanet = yes
| name = 1627 Ivar
| background = #FFC2E0
| image = 1627Ivar (Lightcurve Inversion).png
| image_scale =
| caption = Light-curve-based 3D-model of Ivar
| discovered = 25 September 1929
| discoverer = E. Hertzsprung
| discovery_site = Johannesburg Obs.
{{small|(Leiden Southern Station)}}
| mpc_name = (1627) Ivar
| alt_names = 1929 SH{{·}}1957 NA
1957 XA
| named_after = Ivar Hertzsprung
{{small|(discoverer's brother)}}
| epoch = 4 September 2017 (JD 2458000.5)
| uncertainty = 0
| observation_arc = 87.62 yr (32,002 days)
| aphelion = 2.6015 AU
| perihelion = 1.1240 AU
| time_periastron = 2023-Sep-09
| semimajor = 1.8628 AU
| eccentricity = 0.3966
| period = 2.54 yr (929 days)
| mean_anomaly = 229.02°
| mean_motion = {{Deg2DMS|0.3877|sup=ms}} / day
| inclination = 8.4513°
| asc_node = 133.14°
| arg_peri = 167.76°
| moid = 0.1117 AU{{·}}43.5 LD
| dimensions = ≈15×6×6 km
{{val|8.370|0.075}} km
9.12 km
{{val|9.9|2.8}} km
{{val|10.2}} km
| rotation = {{val|4.795}} h
{{val|4.795|0.002}} h
{{val|4.795170}} h
{{val|4.7954|0.006}} h
{{val|4.796}} h
{{val|4.7961|0.0001}} h
{{val|4.797}} h
{{val|4.798}} h
{{val|4.80}} h
| albedo = {{val|0.09|0.12}}
{{val|0.117}}
{{val|0.128|0.123}}
{{val|0.134|0.025}}
0.15
0.151 {{small|(taken)}}
| spectral_type = S {{small|(Tholen)}}{{·}}S {{small|(SMASS)}}
Srw{{·}}S
B–V = 0.872
U–B = 0.459
| abs_magnitude = {{val|12.87|0.1}}{{·}}12.87{{·}}12.90{{·}}{{val|12.99|0.25}}{{·}}13.00{{·}}13.17{{·}}13.2{{·}}{{val|13.22|0.23}}{{·}}13.24
}}
1627 Ivar (provisional designation {{mp|1929 SH}}) is an elongated stony asteroid and near-Earth object of the Amor group, approximately 15×6×6 km.{{Cite journal|last1=Crowell|first1=Jenna L.|last2=Howell|first2=Ellen S.|author2-link=Ellen Howell|last3=Magri|first3=Christopher|last4=Nolan|first4=Michael C.|last5=Fernández|first5=Yanga R.|last6=Richardson|first6=James E.|last7=Warner|first7=Brian D.|last8=Marshall|first8=Sean E.|last9=Springmann|first9=Alessondra|date=July 2017|title=Radar and Lightcurve Shape Model of Near-Earth Asteroid (1627) Ivar|journal=Icarus|volume=291|pages=254–267|doi=10.1016/j.icarus.2016.11.008|issn=0019-1035|bibcode=2017Icar..291..254C}} It was discovered on 25 September 1929, by Danish astronomer Ejnar Hertzsprung at Leiden Southern Station, annex to the Johannesburg Observatory in South Africa. It was named after Ivar Hertzsprung, brother of the discoverer. 1627 Ivar was the first asteroid to be imaged by radar, in July 1985 by the Arecibo Observatory.[https://history.nasa.gov/SP-4218/ch9.htm To See the Unseen, A History of Planetary Radar Astronomy - chapter 9], Andrew J. Butrica, The NASA History Series
Classification and orbit
Ivar orbits the Sun at a distance of 1.1–2.6 AU once every 2 years and 6 months (929 days). Its orbit has an eccentricity of 0.40 and an inclination of 8° with respect to the ecliptic. Ivar's observation arc begins with its official discovery observation in 1929, as no precoveries were taken, and no prior identifications were made.
It has an Earth minimum orbit intersection distance of {{convert |0.1117 |AU |km |abbr=on |lk=off |sigfig=3}} which corresponds to 43.5 lunar distances. The eccentric Amor asteroid is also a Mars-crosser. In August 2074, it will pass Earth at 0.141 AU, closer than it actually approached Mars in July 1975 (0.150 AU).
Physical characteristics
In the SMASS and Tholen taxonomic scheme, Ivar is characterized as a common stony S-type asteroid.
= Rotation period =
A large number of rotational lightcurves of Ivar have been obtained from photometric observations since 1985 (see infobox). They give a well-defined rotation period between 4.795 and 4.80 hours with a brightness variation between 0.27 and 1.40 magnitude, indicative of its non-spheroidal shape (also see 3D-model image).{{Cite journal|last1=Skiff |first1=Brian A.|last2=Bowell|first2=Edward|last3=Koehn|first3= Bruce W.|last4=Sanborn|first4=Jason J.|last5=McLelland|first5=Kyle P.|last6=Warner|first6=Brian D.|date=July 2012|title=Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS) - 2008 May through 2008 December|journal=Minor Planet Bulletin|language=en|volume=39|issue=3|pages=111|issn=1052-8091|bibcode=2012MPBu...39..111S}} New radar and visual observations refined the period to 4.7951689 ± 0.0000026 hours. Future photometric observations will show whether the YORP effect will slowly change the body's spin rate (as seen with 1862 Apollo).
In 1985, the body was observed with radar from the Arecibo Observatory in Puerto Rico at a distance of 0.20 AU. The measured radar cross-section was 7.5 square kilometers. It was the first asteroid to be imaged by radar. Radar observations have been performed again in June & July 2013 and July 2018.
= Diameter and albedo =
According to the EXPLORENEOs survey carried out by the Spitzer Space Telescope, thermal infrared observations by the Keck Observatory, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, and thermal modeling by Alan Harris, Ivar measures between 8.37 and 10.2 kilometers in diameter, and it surface has an albedo between 0.09 and 0.15. The Collaborative Asteroid Lightcurve Link adopts an albedo of 0.151 and a diameter of 9.12 kilometers with an absolute magnitude of 12.87. According to model based on radar and photometric observations Ivar is an elongated asteroid with maximum extensions along the three body-fixed coordinates being 15.15 × 6.25 × 5.66 km ± 10%.
Naming
This minor planet was named by the discoverer in honor of his late brother Ivar Hertzsprung. The official {{MoMP|1627|naming citation}} was published by the Minor Planet Center in February 1959 ({{small|M.P.C. 1860}}).
References
{{reflist|refs=
|title = JPL Small-Body Database Browser: 1627 Ivar (1929 SH)
|url = https://ssd.jpl.nasa.gov/tools/sbdb_lookup.html#/?sstr=Ivar&view=OPC
|publisher = Jet Propulsion Laboratory
|accessdate = 4 June 2017}}
|title = Dictionary of Minor Planet Names – (1627) Ivar
|last = Schmadel | first = Lutz D.
|publisher = Springer Berlin Heidelberg
|page = 129
|date = 2007
|isbn = 978-3-540-00238-3
|doi = 10.1007/978-3-540-29925-7_1628 |chapter = (1627) Ivar }}
|title = 1627 Ivar (1929 SH)
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=1627
|accessdate = 28 December 2016}}
|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 – 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|bibcode = 2009dmpn.book.....S
}}
|display-authors = 6
|first1 = S. J. |last1 = Ostro
|first2 = D. B. |last2 = Campbell
|first3 = J. F. |last3 = Chandler
|first4 = I. I. |last4 = Shapiro
|first5 = A. A. |last5 = Hine
|first6 = R. |last6 = Velez
|first7 = R. F. |last7 = Jurgens
|first8 = K. D. |last8 = Rosema
|first9 = R. |last9 = Winkler
|first10 = D. K. |last10 = Yeomans
|date = October 1991
|title = Asteroid radar astrometry
|journal = Astronomical Journal
|volume = 102 |pages = 1490–1502.ResearchsupportedbyNASA
|issn = 0004-6256
|bibcode = 1991AJ....102.1490O
|doi = 10.1086/115975}}
|title = LCDB Data for (1627) Ivar
|publisher = Asteroid Lightcurve Database (LCDB)
|url = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=1627%7CIvar
|accessdate = 28 December 2016}}
|author = Harris, Alan W.
|date = February 1998
|title = A Thermal Model for Near-Earth Asteroids
|journal = Icarus
|volume = 131
|issue = 2
|pages = 291–301
|bibcode = 1998Icar..131..291H
|doi = 10.1006/icar.1997.5865}}
|first1 = Marco |last1 = Delbó
|first2 = Alan W. |last2 = Harris
|first3 = Richard P. |last3 = Binzel
|first4 = Petr |last4 = Pravec
|first5 = John K. |last5 = Davies
|date = November 2003
|title = Keck observations of near-Earth asteroids in the thermal infrared
|journal = Icarus
|volume = 166
|issue = 1
|pages = 116–130
|bibcode = 2003Icar..166..116D
|doi = 10.1016/j.icarus.2003.07.002}}
|display-authors = 6
|first1 = Michael |last1 = Mueller
|first2 = M. |last2 = Delbo'
|first3 = J. L. |last3 = Hora
|first4 = D. E. |last4 = Trilling
|first5 = B. |last5 = Bhattacharya
|first6 = W. F. |last6 = Bottke
|first7 = S. |last7 = Chesley
|first8 = J. P. |last8 = Emery
|first9 = G. |last9 = Fazio
|first10 = A. W. |last10 = Harris
|first11 = A. |last11 = Mainzer
|first12 = M. |last12 = Mommert
|first13 = B. |last13 = Penprase
|first14 = H. A. |last14 = Smith
|first15 = T. B. |last15 = Spahr
|first16 = J. A. |last16 = Stansberry
|first17 = C. A. |last17 = Thomas
|date = April 2011
|title = ExploreNEOs. III. Physical Characterization of 65 Potential Spacecraft Target Asteroids
|journal = The Astronomical Journal
|volume = 141
|issue = 4
|page = 9
|bibcode = 2011AJ....141..109M
|doi = 10.1088/0004-6256/141/4/109
|s2cid = 44827674 |url = https://authors.library.caltech.edu/23152/1/Mueller2011p13239Astron_J.pdf}}
|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 }}
|first1 = A. W. |last1 = Harris
|first2 = J. W. |last2 = Young
|date = June 1985
|title = Photometric Results for Earth Approaching Asteroids.
|journal = Bulletin of the American Astronomical Society
|volume = 17
|page = 726
|bibcode = 1985BAAS...17R.726H}}
|first1 = D. F. |last1 = Lupishko
|first2 = F. P. |last2 = Velichko
|first3 = V. G. |last3 = Shevchenko
|date = October 1986
|title = The asteroid 1627 Ivar – UBV photometry, period, and sense of rotation
|journal = Kinematika I Fizika Nebesnykh Tel
|volume = 2
|pages = 39–43
|issn = 0233-7665
|bibcode = 1986KFNT....2...39L}}
|display-authors = 6
|first1 = G. |last1 = Hahn
|first2 = P. |last2 = Magnusson
|first3 = A. W. |last3 = Harris
|first4 = J. W. |last4 = Young
|first5 = L. A. |last5 = Belkora
|first6 = N. J. |last6 = Fico
|first7 = D. F. |last7 = Lupishko
|first8 = V. G. |last8 = Shevchenko
|first9 = F. P. |last9 = Velichko
|first10 = R. |last10 = Burchi
|first11 = G. |last11 = Ciunci
|first12 = M. |last12 = di Martino
|first13 = H. |last13 = Debehogne
|date = April 1989
|title = Physical studies of Apollo-Amor asteroids – UBVRI photometry of 1036 Ganymed and 1627 Ivar
|journal = Icarus
|volume = 78 |issue = 2 |pages = 363–381
|issn = 0019-1035
|bibcode = 1989Icar...78..363H
|doi = 10.1016/0019-1035(89)90184-X}}
|first1 = Petr |last1 = Pravec
|first2 = Lenka |last2 = Sarounová
|first3 = Marek |last3 = Wolf
|date = December 1996
|title = Lightcurves of 7 Near-Earth Asteroids
|journal = Icarus
|volume = 124
|issue = 2
|pages = 471–482
|bibcode = 1996Icar..124..471P
|doi = 10.1006/icar.1996.0223}}
|first1 = L. L. |last1 = Kiss
|first2 = Gy. |last2 = Szabó
|first3 = K. |last3 = Sárneczky
|date = November 1999
|title = CCD photometry and new models of 5 minor planets
|journal = Astronomy and Astrophysics Supplement
|volume = 140
|pages = 21–28
|bibcode = 1999A&AS..140...21K
|doi = 10.1051/aas:1999115
|arxiv = astro-ph/9909159|s2cid = 16733071
}}
|display-authors = 6
|first1 = Mikko |last1 = Kaasalainen
|first2 = Petr |last2 = Pravec
|first3 = Yurij N. |last3 = Krugly
|first4 = Lenka |last4 = Sarounová
|first5 = Johanna |last5 = Torppa
|first6 = Jenni |last6 = Virtanen
|first7 = Sanna |last7 = Kaasalainen
|first8 = Anders |last8 = Erikson
|first9 = Andreas |last9 = Nathues
|first10 = Josef |last10 = Durech
|first11 = Marek |last11 = Wolf
|first12 = Johan S. V. |last12 = Lagerros
|first13 = Mats |last13 = Lindgren
|first14 = Claes-Ingvar |last14 = Lagerkvist
|first15 = Robert |last15 = Koff
|first16 = John |last16 = Davies
|first17 = Rita |last17 = Mann
|first18 = Peter |last18 = Kusnirák
|first19 = Ninel M. |last19 = Gaftonyuk
|first20 = Vasilij G. |last20 = Shevchenko
|first21 = Vasilij G. |last21 = Chiorny
|first22 = Irina N. |last22 = Belskaya
|date = January 2004
|title = Photometry and models of eight near-Earth asteroids
|journal = Icarus
|volume = 167
|issue = 1
|pages = 178–196
|bibcode = 2004Icar..167..178K
|doi = 10.1016/j.icarus.2003.09.012}}
|first1 = Brian A. |last1 = Skiff
|first2 = Edward |last2 = Bowell
|first3 = Bruce W. |last3 = Koehn
|first4 = Jason J. |last4 = Sanborn
|first5 = Kyle P. |last5 = McLelland
|first6 = Brian D. |last6 = Warner
|date = July 2012
|title = Lowell Observatory Near-Earth Asteroid Photometric Survey (NEAPS) – 2008 May through 2008 December
|journal = The Minor Planet Bulletin
|volume = 39
|issue = 3
|pages = 111–130
|issn = 1052-8091
|bibcode = 2012MPBu...39..111S}}
|author = Warner, Brian D.
|date = January 2014
|title = Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2013 June–September
|journal = The Minor Planet Bulletin
|volume = 41
|issue = 1
|pages = 41–47
|pmid = 32457957
|pmc = 7249616
|issn = 1052-8091
|bibcode = 2014MPBu...41...41W}}
|author = Warner, Brian D.
|date = July 2015
|title = Near-Earth Asteroid Lightcurve Analysis at CS3-Palmer Divide Station: 2015 January – March
|journal = The Minor Planet Bulletin
|volume = 42
|issue = 3
|pages = 172–183
|pmid = 32455355
|pmc = 7244166
|issn = 1052-8091
|bibcode = 2015MPBu...42..172W}}
|first1 = J. |last1 = Hanus
|first2 = M. |last2 = Delbo'
|first3 = J. |last3 = Durech
|first4 = V. |last4 = Alí-Lagoa
|date = August 2015
|title = Thermophysical modeling of asteroids from WISE thermal infrared data – Significance of the shape model and the pole orientation uncertainties
|journal = Icarus
|volume = 256
|pages = 101–116
|bibcode = 2015Icar..256..101H
|doi = 10.1016/j.icarus.2015.04.014
|arxiv = 1504.04199|s2cid = 118480799
}}
|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 – Preliminary results
|journal = Icarus
|volume = 261
|pages = 34–47
|bibcode = 2015Icar..261...34V
|doi = 10.1016/j.icarus.2015.08.007
|arxiv = 1506.00762|s2cid = 53493339 }}
|first1 = B. |last1 = Carry
|first2 = E. |last2 = Solano
|first3 = S. |last3 = Eggl
|first4 = F. E. |last4 = DeMeo
|date = April 2016
|title = Spectral properties of near-Earth and Mars-crossing asteroids using Sloan photometry
|journal = Icarus
|volume = 268
|pages = 340–354
|bibcode = 2016Icar..268..340C
|doi = 10.1016/j.icarus.2015.12.047
|arxiv = 1601.02087 |s2cid = 119258489
}}
|display-authors = 6
|first1 = A. |last1 = Mainzer
|first2 = T. |last2 = Grav
|first3 = J. |last3 = Masiero
|first4 = J. |last4 = Bauer
|first5 = E. |last5 = Wright
|first6 = R. M. |last6 = Cutri
|first7 = R. S. |last7 = McMillan
|first8 = M. |last8 = Cohen
|first9 = M. |last9 = Ressler
|first10 = P. |last10 = Eisenhardt
|date = August 2011
|title = Thermal Model Calibration for Minor Planets Observed with Wide-field Infrared Survey Explorer/NEOWISE
|journal = The Astrophysical Journal
|volume = 736
|issue = 2
|page = 9
|bibcode = 2011ApJ...736..100M
|doi = 10.1088/0004-637X/736/2/100
|citeseerx= 10.1.1.472.4936|s2cid = 50794389 }}
|display-authors = 6
|first1 = C. A. |last1 = Thomas
|first2 = D. E. |last2 = Trilling
|first3 = J. P. |last3 = Emery
|first4 = M. |last4 = Mueller
|first5 = J. L. |last5 = Hora
|first6 = L. A. M. |last6 = Benner
|first7 = B. |last7 = Bhattacharya
|first8 = W. F. |last8 = Bottke
|first9 = S. |last9 = Chesley
|first10 = M. |last10 = Delbó
|first11 = G. |last11 = Fazio
|first12 = A. W. |last12 = Harris
|first13 = A. |last13 = Mainzer
|first14 = M. |last14 = Mommert
|first15 = A. |last15 = Morbidelli
|first16 = B. |last16 = Penprase
|first17 = H. A. |last17 = Smith
|first18 = T. B. |last18 = Spahr
|first19 = J. A. |last19 = Stansberry
|date = September 2011
|title = ExploreNEOs. V. Average Albedo by Taxonomic Complex in the Near-Earth Asteroid Population
|journal = The Astronomical Journal
|volume = 142
|issue = 3
|page = 12
|bibcode = 2011AJ....142...85T
|doi = 10.1088/0004-6256/142/3/85|doi-access= free
}}
|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|s2cid = 119278697
}}
}}
External links
- [https://web.archive.org/web/20091220092940/http://unicorn.eis.uva.es/neodys/index.php?pc=1.1.0&n=1627 NeoDys entry on Ivar]
- [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|1627}}
- {{ESA-SSA|1627|Ivar}}
- {{JPL small body}}
{{Minor planets navigator |1626 Sadeya |number=1627 |1628 Strobel}}
{{Small Solar System bodies}}
{{Authority control}}
{{DEFAULTSORT:Ivar}}