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{{Use dmy dates|date=October 2019}}
{{Infobox planet
{{Infobox planet
| minorplanet = yes
| minorplanet = yes
| name = 1995 Hajek
| name = 1995 Hajek
| background = #FFFFC0
| background = #D6D6D6
| image =
| image =
| image_size =
| caption =
| caption =
| discovery_ref = &thinsp;<ref name="jpldata" /><ref name="MPC-Hajek" />
| discovery_ref = <ref name="jpldata" />
| discovered = 26 October 1971
| discovered = 26 October 1971
| discoverer = [[Luboš Kohoutek|L. Kohoutek]]
| discoverer = [[Luboš Kohoutek|L. Kohoutek]]
| discovery_site = [[Bergedorf Observatory|Bergedorf Obs.]]
| discovery_site = [[Bergedorf Observatory|Bergedorf Obs.]]
| mp_name = 1995 Hajek
| mpc_name = (1995) Hajek
| alt_names = {{mp|1971 UP|1}}{{·}}1941 EA
| alt_names = {{mp|1971 UP|1}}{{·}}1941 EA
| named_after = [[Tadeáš Hájek]]<br />{{small|(astronomer)}}<ref name="springer" />
| named_after = [[Tadeáš Hájek]] {{small|(astronomer)}}<ref name="springer" />
| mp_category = [[main-belt]]{{·}}{{small|(inner)}}&thinsp;<ref name="lcdb" />
| mp_category = [[main-belt]]{{·}}{{small|([[Kirkwood gap|middle]])}}<ref name="lcdb" />
| orbit_ref = &thinsp;<ref name="jpldata" />
| orbit_ref = <ref name="jpldata" />
| epoch = 27 June 2015 ([[Julian day|JD]] 2457200.5)
| epoch = 4 September 2017 ([[Julian day|JD]] 2458000.5)
| uncertainty = 0
| uncertainty = 0
| observation_arc = {{nowrap|74.67 yr (27,275 days)}}
| observation_arc = 76.21 yr (27,836 days)
| aphelion = 2.6659 [[Astronomical unit|AU]]
| aphelion = 2.6677 [[Astronomical unit|AU]]
| perihelion = 2.3924 AU
| perihelion = 2.3911 AU
| semimajor = 2.5292 AU
| semimajor = 2.5294 AU
| eccentricity = 0.0540
| eccentricity = 0.0547
| period = 4.02 [[Julian year (astronomy)|yr]] (1,469 days)
| period = 4.02 [[Julian year (astronomy)|yr]] (1,469 days)
| mean_anomaly = 170.20[[degree (angle)|°]]
| mean_anomaly = 6.1573[[Degree (angle)|°]]
| inclination = 10.822°
| mean_motion = {{Deg2DMS|0.2450|sup=ms}} / day
| asc_node = 47.238°
| inclination = 10.825°
| arg_peri = 134.52°
| asc_node = 47.232°
| arg_peri = 134.65°
| dimensions = {{val|15.29|1.04}} km<ref name="AKARI" /><br />{{val|12.683|0.288}} km<ref name="WISE" /><br />{{val|14.45|2.58}} km<ref name="Masiero-2012" /><br />6.50 km {{small|(calculated)}}<ref name="lcdb" /><br />{{val|10|4}} km {{small|(magnitude)}}<ref name="h" />
| dimensions = 6.50 km {{small|(calculated)}}<ref name="lcdb" /><br />{{val|12.683|0.288}} km<ref name="WISE" /><ref name="Masiero-2011" /><br />{{val|14.45|2.58}} km<ref name="Masiero-2012" /><br />{{val|15.29|1.04}} km<ref name="AKARI" />
| rotation = 10 [[hour|h]]<ref name="geneva-obs" />
| rotation = {{val|10|}} [[Hour|h]]<ref name="geneva-obs" />
| albedo = {{val|0.063|0.010}}<ref name="AKARI" /><br />{{val|0.0833|0.0249}}<ref name="WISE" /><br />{{val|0.040|0.025}}<ref name="Masiero-2012" /><br />0.20 {{small|(assumed)}}<ref name="lcdb" />
| albedo = {{val|0.040|0.025}}<ref name="Masiero-2012" /><ref name="Masiero-2011" /><br />{{val|0.063|0.010}}<ref name="AKARI" /><br />{{val|0.0833|0.0249}}<ref name="WISE" /><br />0.20 {{small|(assumed)}}<ref name="lcdb" />
| spectral_type = [[X-type asteroid|X]]&thinsp;<ref name="lcdb" /><ref name="Shui-1995" />
| spectral_type = [[P-type asteroid|P]]<ref name="WISE" />{{·}}[[X-type asteroid|X]]<ref name="lcdb" /><ref name="Veres-2015" /><ref name="Shui-1995" />
| abs_magnitude = 13.3<ref name="jpldata" />
| abs_magnitude = 12.80<ref name="WISE" /><ref name="AKARI" />{{·}}{{val|13.06|0.33}}<ref name="Veres-2015" />{{·}}13.3<ref name="jpldata" /><ref name="lcdb" /><ref name="Masiero-2012" />
}}
}}


'''1995 Hajek''', provisional designation {{mp|1971 UP|1}}, is a metallic [[asteroid]] from the inner regions of the [[asteroid belt]]. It was discovered by Czech astronomer [[Luboš Kohoutek]] at the [[Bergedorf Observatory]] in Hamburg, Germany, on 26 October 1971.<ref name="MPC-Hajek" />
'''1995 Hajek''', provisional designation {{mp|1971 UP|1}}, is a metallic [[asteroid]] from the middle region of the [[asteroid belt]], approximately 13 kilometers in diameter.


It was discovered on 26 October 1971, by Czech astronomer [[Luboš Kohoutek]] at the [[Bergedorf Observatory]] in Hamburg, Germany.<ref name="MPC-Hajek" /> It was named after Renaissance astronomer [[Tadeáš Hájek]].<ref name="springer" />
The asteroid orbits the Sun at a distance of 2.4–2.7&nbsp;[[Astronomical unit|AU]] once every 4.02 years (1,469 days). Its orbit shows an [[orbital eccentricity|eccentricity]] of 0.05 and is [[orbital inclination|tilted]] by 11 degrees to the plane of the [[ecliptic]]. It has a provisional rotation period of 10 hours<ref name="geneva-obs" /> and measurements of its spectral properties identified it as a metallic [[X-type asteroid]].<ref name="lcdb" /><ref name="Shui-1995" />


== Orbit and classification ==
Observations by the [[Akari (satellite)|Akari]] and [[Wide-field Infrared Survey Explorer|WISE]] satellites, as well as calculations by the ''Collaborative Asteroid Lightcurve Link'' (CALL), rendered a divergent estimated of the body's diameter in a large range of 6.5 to 15.3 kilometers. Likewise, the body's [[astronomical albedo|albedo]] also varies between 0.04 and 0.08 for the satellite-based observations, while CALL assumes an albedo of 0.20.<ref name="lcdb" /> These contrasting albedo and diameter figures closely correspond to a generic magnitude-to-diameter conversion, where, for an absolute magnitude of 13.3, the body's diameter is in the range of about 6 to 14 kilometers, based on an albedo between 0.05 and 0.25.<ref name="h" />


''Hajek'' orbits the Sun in the [[Kirkwood gap|middle]] main-belt at a distance of 2.4–2.7&nbsp;[[Astronomical unit|AU]] once every 4.02 years (1,469 days). Its orbit has an [[orbital eccentricity|eccentricity]] of 0.05 and an [[orbital inclination|inclination]] of 11[[Degree (angle)|°]] with respect to the [[ecliptic]].<ref name="jpldata" /> It was first identified as {{mp|1941 EA}} at Heidelberg in 1941. The body's used observation was a [[precovery]] taken at [[Palomar Observatory]] in 1951, extending its [[observation arc]] by 20 years prior to the official discovery observation at Heidelberg.
The minor planet is named after the Bohemian astronomer [[Tadeáš Hájek]] (1525–1600), better known by his Latinized name, Thaddaeus Hagecius. He was one of the founders of modern stellar and cometary astronomy, who studied the [[Great Comet of 1577]] and the supernova [[SN 1572]], also known as ''Tycho's Nova''. The lunar crater ''[[Hagecius (crater)|Hagecius]]'' is also named in his honour.<ref name="springer" />

== Physical characteristics ==

A first rotational [[lightcurve]] of ''Hajek'' was obtained by French amateur astronomers Alain Klotz, Marc Rieugné, and Pierre Thierry in October 2013. It gave a provisional [[rotation period]] of 10 hours with a brightness variation of 0.10 [[Magnitude (astronomy)|magnitude]] ({{small|[[LCDB quality code|U=1+]]}}).<ref name="geneva-obs" />

''Hajek'' has the [[Asteroid spectral types|spectral properties]] of a metallic [[X-type asteroid]].<ref name="lcdb" /><ref name="Veres-2015" /><ref name="Shui-1995" /> It is also classified as a dark [[P-type asteroid]] by NASA's [[Wide-field Infrared Survey Explorer]] (WISE).<ref name="WISE" />

According to the surveys carried out by the Japanese [[Akari (satellite)|Akari]] satellite and WISE space-telescope with its subsequent [[NEOWISE]] mission, ''Hajek'' measures between 12.7 and 15.3 kilometers in diameter and its surface has an [[astronomical albedo|albedo]] of 0.040 and 0.083.<ref name="WISE" /><ref name="Masiero-2012" /><ref name="AKARI" /> The ''Collaborative Asteroid Lightcurve Link'' strongly disagrees with the space-based observations and assumes a standard albedo for stony asteroids of 0.200 and calculates a much smaller diameter of 6.5 kilometers.<ref name="lcdb" /> These contrasting albedo and diameter figures closely correspond to a generic magnitude-to-diameter conversion, where, for an absolute magnitude of 13.3, the body's diameter is in the range of 6 to 14 kilometers, based on an albedo between 0.05 and 0.25.<ref name="h" />

== Naming ==

This [[minor planet]] was named after the Bohemian astronomer [[Tadeáš Hájek]] (1525–1600), better known by his Latinized name, Thaddaeus Hagecius. He was one of the founders of modern stellar and cometary astronomy, who studied the [[Great Comet of 1577]] and the supernova [[SN 1572]], also known as ''Tycho's Nova''. The lunar crater ''[[Hagecius (crater)|Hagecius]]'' is also named in his honour.<ref name="springer" /> The official {{MoMP|1995|naming citation}} was published by the [[Minor Planet Center]] on 1 April 1978 ({{small|[[Minor Planet Circulars|M.P.C.]] 4358}}).<ref name="DoMP-Circular-dates" />


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

|refs=
<ref name="jpldata">{{cite web
|type = 2017-06-04 last obs.
|title = JPL Small-Body Database Browser: 1995 Hajek (1971 UP1)
|url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2001995
|archive-url = https://web.archive.org/web/20161220081623/http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2001995
|archive-date = 20 December 2016
|publisher = [[Jet Propulsion Laboratory]]
|access-date = 1 July 2017}}</ref>

<ref name="springer">{{cite book
|title = Dictionary of Minor Planet Names – (1995) Hajek
|last = Schmadel | first = Lutz D.
|publisher = [[Springer Berlin Heidelberg]]
|page = 161
|date = 2007
|isbn = 978-3-540-00238-3
|doi = 10.1007/978-3-540-29925-7_1996 |chapter = (1995) Hajek }}</ref>

<ref name="MPC-Hajek">{{cite web
|title = 1995 Hajek (1971 UP1)
|work = Minor Planet Center
|url = https://www.minorplanetcenter.net/db_search/show_object?object_id=1995
|access-date = 8 December 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 – 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
}}</ref>

<ref name="geneva-obs">{{cite web
|title = Asteroids and comets rotation curves – (1995) Hajek
|last = Behrend |first = Raoul
|publisher = [[Geneva Observatory]]
|url = http://obswww.unige.ch/~behrend/page4cou.html#001995
|access-date = 8 December 2016}}</ref>

<ref name="h">{{cite web
|title = Asteroid Size Estimator
|publisher = CNEOS NASA/JPL
|url = https://cneos.jpl.nasa.gov/tools/ast_size_est.html
|access-date = 21 October 2019}}</ref>


<ref name="Shui-1995">{{cite journal
<ref name="Shui-1995">{{cite journal
Line 54: Line 119:
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=1995Icar..115....1X
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=1995Icar..115....1X
|journal = Icarus
|journal = Icarus
|volume = 115
|issue = 1
|pages = 1–35
|pages = 1–35
|issn = 0019-1035
|issn = 0019-1035
|bibcode = 1995Icar..115....1X
|bibcode = 1995Icar..115....1X
|doi = 10.1006/icar.1995.1075
|doi = 10.1006/icar.1995.1075
|access-date= December 2015}}</ref>
|access-date= 17 December 2015}}</ref>


<ref name="lcdb">{{cite web
<ref name="lcdb">{{cite web
|title=LCDB Data for (1995) Hajek
|title = LCDB Data for (1995) Hajek
|publisher=Asteroid Lightcurve Database (LCDB)
|publisher = Asteroid Lightcurve Database (LCDB)
|url=http://www.minorplanet.info/PHP/GenerateALCDEFPage_Local.php?AstInfo=1995%7CHajek
|url = http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=1995%7CHajek
|accessdate=December 2015}}</ref>
|access-date = 8 December 2016}}</ref>

<ref name="jpldata">{{cite web
|type=2015-11-21 last obs.
|title=JPL Small-Body Database Browser: 1995 Hajek (1971 UP1)
|url=http://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2001995
|publisher=Jet Propulsion Laboratory
|accessdate=December 2015}}</ref>

<ref name="springer">{{cite book
|url=http://link.springer.com/referenceworkentry/10.1007/978-3-540-29925-7_1996
|title=Dictionary of Minor Planet Names – (1995) Hajek
|last=Schmadel |first=Lutz D.
|publisher=Springer Berlin Heidelberg
|page=161
|date=2003
|isbn=978-3-540-29925-7
|accessdate=October 2015}}</ref>

<ref name="MPC-Hajek">{{cite web
|title=1995 Hajek (1971 UP1)
|work=Minor Planet Center
|url=http://www.minorplanetcenter.net/db_search/show_object?object_id=1995
|accessdate=October 2015}}</ref>

<ref name="geneva-obs">{{cite web
|author=Behrend, R.
|title=Asteroids and comets rotation curves—(1995) Hajek
|url=http://obswww.unige.ch/~behrend/page4cou.html#001995
|publisher=Geneva Observatory
|date=December 2003
|accessdate=October 2015}}</ref>

<ref name="MPC-Hajek">{{cite web
|title=1995 Hajek (1971 UP1)
|work=Minor Planet Center
|url=http://www.minorplanetcenter.net/db_search/show_object?object_id=1995
|accessdate=December 2015}}</ref>


<ref name="AKARI">{{cite journal
<ref name="AKARI">{{cite journal
|display-authors = 6
|display-authors = 6
|author = Usui, Fumihiko
|first1 = Fumihiko |last1 = Usui
|author2 = Kuroda, Daisuke
|first2 = Daisuke |last2 = Kuroda
|author3 = Müller, Thomas G.
|first3 = Thomas G. |last3 = Müller
|author4 = Hasegawa, Sunao
|first4 = Sunao |last4 = Hasegawa
|author5 = Ishiguro, Masateru
|first5 = Masateru |last5 = Ishiguro
|author6 = Ootsubo, Takafumi
|first6 = Takafumi |last6 = Ootsubo
|author7 = Ishihara, Daisuke
|first7 = Daisuke |last7 = Ishihara
|author8 = Kataza, Hirokazu
|first8 = Hirokazu |last8 = Kataza
|author9 = Takita, Satoshi
|first9 = Satoshi |last9 = Takita
|author10 = Oyabu, Shinki
|first10 = Shinki |last10 = Oyabu
|author11 = Ueno, Munetaka
|first11 = Munetaka |last11 = Ueno
|author12 = Matsuhara, Hideo
|first12 = Hideo |last12 = Matsuhara
|author13 = Onaka, Takashi
|first13 = Takashi |last13 = Onaka
|date = October 2011
|date = October 2011
|title = Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey
|title = Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011PASJ...63.1117U
|journal = Publications of the Astronomical Society of Japan
|journal = Publications of the Astronomical Society of Japan
|volume = 63
|volume = 63
Line 127: Line 156:
|bibcode = 2011PASJ...63.1117U
|bibcode = 2011PASJ...63.1117U
|doi = 10.1093/pasj/63.5.1117
|doi = 10.1093/pasj/63.5.1117
}} ([http://vizier.cfa.harvard.edu/viz-bin/VizieR-5?-source=J/PASJ/63/1117/acua_v1&Num=1995 online], [https://core.ac.uk/download/pdf/43545172.pdf AcuA catalog p. 153])</ref>
|access-date= December 2015}}</ref>


<ref name="WISE">{{cite journal
<ref name="WISE">{{cite journal
|display-authors = 6
|display-authors = 6
|author = Mainzer, A.
|first1 = A. |last1 = Mainzer
|author2 = Grav, T.
|first2 = T. |last2 = Grav
|author3 = Masiero, J.
|first3 = J. |last3 = Masiero
|author4 = Hand, E.
|first4 = E. |last4 = Hand
|author5 = Bauer, J.
|first5 = J. |last5 = Bauer
|author6 = Tholen, D.
|first6 = D. |last6 = Tholen
|author7 = McMillan, R. S.
|first7 = R. S. |last7 = McMillan
|author8 = Spahr, T.
|first8 = T. |last8 = Spahr
|author9 = Cutri, R. M.
|first9 = R. M. |last9 = Cutri
|author10 = Wright, E.
|first10 = E. |last10 = Wright
|author11 = Watkins, J.
|first11 = J. |last11 = Watkins
|author12 = Mo, W.
|first12 = W. |last12 = Mo
|author13 = Maleszewski, C.
|first13 = C. |last13 = Maleszewski
|date = November 2011
|date = November 2011
|title = NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results
|title = NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011ApJ...741...90M
|journal = The Astrophysical Journal
|journal = The Astrophysical Journal
|volume = 741
|volume = 741
Line 153: Line 181:
|bibcode = 2011ApJ...741...90M
|bibcode = 2011ApJ...741...90M
|doi = 10.1088/0004-637X/741/2/90
|doi = 10.1088/0004-637X/741/2/90
|access-date= December 2015|arxiv = 1109.6407 }}</ref>
|arxiv = 1109.6407|s2cid = 35447010 }}</ref>


<ref name="Masiero-2012">{{cite journal
<ref name="Masiero-2012">{{cite journal
|display-authors = 6
|author = Masiero, Joseph R.
|author2 = Mainzer, A. K.
|first1 = Joseph R. |last1 = Masiero
|author3 = Grav, T.
|first2 = A. K. |last2 = Mainzer
|author4 = Bauer, J. M.
|first3 = T. |last3 = Grav
|author5 = Cutri, R. M.
|first4 = J. M. |last4 = Bauer
|author6 = Nugent, C.
|first5 = R. M. |last5 = Cutri
|author7 = Cabrera, M. S.
|first6 = C. |last6 = Nugent
|first7 = M. S. |last7 = Cabrera
|date = November 2012
|date = November 2012
|title = Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids
|title = Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids
Line 172: Line 201:
|bibcode = 2012ApJ...759L...8M
|bibcode = 2012ApJ...759L...8M
|doi = 10.1088/2041-8205/759/1/L8
|doi = 10.1088/2041-8205/759/1/L8
|access-date= December 2015|arxiv = 1209.5794 }}</ref>
|arxiv = 1209.5794
|s2cid = 46350317 |access-date= 8 December 2016}}</ref>


<ref name="h">{{cite web
<ref name="Veres-2015">{{cite journal
|display-authors = 6
|title=Absolute Magnitude (H)
|first1 = Peter |last1 = Veres
|publisher=NASA/JPL
|first2 = Robert |last2 = Jedicke
|url=http://neo.jpl.nasa.gov/glossary/h.html
|first3 = Alan |last3 = Fitzsimmons
|accessdate=2014-06-24}}</ref>
|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
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015Icar..261...34V
|journal = Icarus
|volume = 261
|pages = 34–47
|bibcode = 2015Icar..261...34V
|doi = 10.1016/j.icarus.2015.08.007
|arxiv = 1506.00762
|s2cid = 53493339 |access-date= 8 December 2016}}</ref>

<ref name="Masiero-2011">{{cite journal
|display-authors = 6
|first1 = Joseph R. |last1 = Masiero
|first2 = A. K. |last2 = Mainzer
|first3 = T. |last3 = Grav
|first4 = J. M. |last4 = Bauer
|first5 = R. M. |last5 = Cutri
|first6 = J. |last6 = Dailey
|first7 = P. R. M. |last7 = Eisenhardt
|first8 = R. S. |last8 = McMillan
|first9 = T. B. |last9 = Spahr
|first10 = M. F. |last10 = Skrutskie
|first11 = D. |last11 = Tholen
|first12 = R. G. |last12 = Walker
|first13 = E. L. |last13 = Wright
|first14 = E. |last14 = DeBaun
|first15 = D. |last15 = Elsbury
|first16 = T. IV |last16 = Gautier
|first17 = S. |last17 = Gomillion
|first18 = A. |last18 = Wilkins
|date = November 2011
|title = Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters
|url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2011ApJ...741...68M
|journal = The Astrophysical Journal
|volume = 741
|issue = 2
|page = 20
|bibcode = 2011ApJ...741...68M
|doi = 10.1088/0004-637X/741/2/68
|arxiv = 1109.4096
|s2cid = 118745497 |access-date= 8 December 2016}}</ref>


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


== External links ==
== External links ==
* [http://www.minorplanet.info/PHP/lcdbsummaryquery.php Asteroid Lightcurve Database (LCDB)], query form ([http://www.minorplanet.info/lightcurvedatabase.html info])
* [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.se/books?id=aeAg1X7afOoC&pg Dictionary of Minor Planet Names], Google books
* [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
* [http://obswww.unige.ch/~behrend/page_cou.html Asteroids and comets rotation curves, CdR] – Observatoire de Genève, Raoul Behrend
* [http://www.minorplanetcenter.net/iau/lists/NumberedMPs000001.html Discovery Circumstances: Numbered Minor Planets (1)-(5000)] – Minor Planet Center
* [https://www.minorplanetcenter.net/iau/lists/NumberedMPs000001.html Discovery Circumstances: Numbered Minor Planets (1)-(5000)] – Minor Planet Center
* {{AstDys|1995}}
* {{JPL small body|title=1995 Hajek (1971 UP1)|id=2001995}}
* {{JPL small body}}


{{Minor planets navigator|1994 Shane|1996 Adams}}
{{Minor planets navigator |1994 Shane |number=1995 |1996 Adams}}
{{Small Solar System bodies}}
{{Small Solar System bodies}}
{{Authority control}}


{{DEFAULTSORT:Hajek}}
{{DEFAULTSORT:Hajek}}
[[Category:Main-belt asteroids|001995]]
[[Category:Background asteroids|001995]]
[[Category:Numbered asteroids|001995]]
[[Category:Discoveries by Luboš Kohoutek]]
[[Category:Asteroids named for people]]
[[Category:Named minor planets]]
[[Category:X-type asteroids|001995]]
[[Category:Astronomical objects discovered in 1971|19711026]]
[[Category:Astronomical objects discovered in 1971|19711026]]
[[Category:X-type asteroids|001995]]
[[Category:Discoveries by Luboš Kohoutek]]


{{Beltasteroid-stub}}

Latest revision as of 19:00, 24 December 2023

1995 Hajek
Discovery[1]
Discovered byL. Kohoutek
Discovery siteBergedorf Obs.
Discovery date26 October 1971
Designations
(1995) Hajek
Named after
Tadeáš Hájek (astronomer)[2]
1971 UP1 · 1941 EA
main-belt · (middle)[3]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc76.21 yr (27,836 days)
Aphelion2.6677 AU
Perihelion2.3911 AU
2.5294 AU
Eccentricity0.0547
4.02 yr (1,469 days)
6.1573°
0° 14m 42s / day
Inclination10.825°
47.232°
134.65°
Physical characteristics
Dimensions6.50 km (calculated)[3]
12.683±0.288 km[4][5]
14.45±2.58 km[6]
15.29±1.04 km[7]
10 h[8]
0.040±0.025[6][5]
0.063±0.010[7]
0.0833±0.0249[4]
0.20 (assumed)[3]
P[4] · X[3][9][10]
12.80[4][7] · 13.06±0.33[9] · 13.3[1][3][6]

1995 Hajek, provisional designation 1971 UP1, is a metallic asteroid from the middle region of the asteroid belt, approximately 13 kilometers in diameter.

It was discovered on 26 October 1971, by Czech astronomer Luboš Kohoutek at the Bergedorf Observatory in Hamburg, Germany.[11] It was named after Renaissance astronomer Tadeáš Hájek.[2]

Orbit and classification

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Hajek orbits the Sun in the middle main-belt at a distance of 2.4–2.7 AU once every 4.02 years (1,469 days). Its orbit has an eccentricity of 0.05 and an inclination of 11° with respect to the ecliptic.[1] It was first identified as 1941 EA at Heidelberg in 1941. The body's used observation was a precovery taken at Palomar Observatory in 1951, extending its observation arc by 20 years prior to the official discovery observation at Heidelberg.

Physical characteristics

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A first rotational lightcurve of Hajek was obtained by French amateur astronomers Alain Klotz, Marc Rieugné, and Pierre Thierry in October 2013. It gave a provisional rotation period of 10 hours with a brightness variation of 0.10 magnitude (U=1+).[8]

Hajek has the spectral properties of a metallic X-type asteroid.[3][9][10] It is also classified as a dark P-type asteroid by NASA's Wide-field Infrared Survey Explorer (WISE).[4]

According to the surveys carried out by the Japanese Akari satellite and WISE space-telescope with its subsequent NEOWISE mission, Hajek measures between 12.7 and 15.3 kilometers in diameter and its surface has an albedo of 0.040 and 0.083.[4][6][7] The Collaborative Asteroid Lightcurve Link strongly disagrees with the space-based observations and assumes a standard albedo for stony asteroids of 0.200 and calculates a much smaller diameter of 6.5 kilometers.[3] These contrasting albedo and diameter figures closely correspond to a generic magnitude-to-diameter conversion, where, for an absolute magnitude of 13.3, the body's diameter is in the range of 6 to 14 kilometers, based on an albedo between 0.05 and 0.25.[12]

Naming

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This minor planet was named after the Bohemian astronomer Tadeáš Hájek (1525–1600), better known by his Latinized name, Thaddaeus Hagecius. He was one of the founders of modern stellar and cometary astronomy, who studied the Great Comet of 1577 and the supernova SN 1572, also known as Tycho's Nova. The lunar crater Hagecius is also named in his honour.[2] The official naming citation was published by the Minor Planet Center on 1 April 1978 (M.P.C. 4358).[13]

References

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  1. ^ a b c d "JPL Small-Body Database Browser: 1995 Hajek (1971 UP1)" (2017-06-04 last obs.). Jet Propulsion Laboratory. Archived from the original on 20 December 2016. Retrieved 1 July 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). "(1995) Hajek". Dictionary of Minor Planet Names – (1995) Hajek. Springer Berlin Heidelberg. p. 161. doi:10.1007/978-3-540-29925-7_1996. ISBN 978-3-540-00238-3.
  3. ^ a b c d e f g "LCDB Data for (1995) Hajek". Asteroid Lightcurve Database (LCDB). Retrieved 8 December 2016.
  4. ^ a b c d e f Mainzer, A.; Grav, T.; Masiero, J.; Hand, E.; Bauer, J.; Tholen, D.; et al. (November 2011). "NEOWISE Studies of Spectrophotometrically Classified Asteroids: Preliminary Results". The Astrophysical Journal. 741 (2): 25. arXiv:1109.6407. Bibcode:2011ApJ...741...90M. doi:10.1088/0004-637X/741/2/90. S2CID 35447010.
  5. ^ a b Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. S2CID 118745497. Retrieved 8 December 2016.
  6. ^ a b c d Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (November 2012). "Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids". The Astrophysical Journal Letters. 759 (1): 5. arXiv:1209.5794. Bibcode:2012ApJ...759L...8M. doi:10.1088/2041-8205/759/1/L8. S2CID 46350317. Retrieved 8 December 2016.
  7. ^ a b c d Usui, Fumihiko; Kuroda, Daisuke; Müller, Thomas G.; Hasegawa, Sunao; Ishiguro, Masateru; Ootsubo, Takafumi; et al. (October 2011). "Asteroid Catalog Using Akari: AKARI/IRC Mid-Infrared Asteroid Survey". Publications of the Astronomical Society of Japan. 63 (5): 1117–1138. Bibcode:2011PASJ...63.1117U. doi:10.1093/pasj/63.5.1117. (online, AcuA catalog p. 153)
  8. ^ a b Behrend, Raoul. "Asteroids and comets rotation curves – (1995) Hajek". Geneva Observatory. Retrieved 8 December 2016.
  9. ^ a b c Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 – Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. S2CID 53493339. Retrieved 8 December 2016.
  10. ^ a b Xu, Shui; Binzel, Richard P.; Burbine, Thomas H.; Bus, Schelte J. (May 1995). "Small main-belt asteroid spectroscopic survey: Initial results". Icarus. 115 (1): 1–35. Bibcode:1995Icar..115....1X. doi:10.1006/icar.1995.1075. ISSN 0019-1035. Retrieved 17 December 2015.
  11. ^ "1995 Hajek (1971 UP1)". Minor Planet Center. Retrieved 8 December 2016.
  12. ^ "Asteroid Size Estimator". CNEOS NASA/JPL. Retrieved 21 October 2019.
  13. ^ Schmadel, Lutz D. (2009). "Appendix – Publication Dates of the MPCs". Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221. Bibcode:2009dmpn.book.....S. doi:10.1007/978-3-642-01965-4. ISBN 978-3-642-01964-7.
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