1075 Helina

{{Short description|Main-belt asteroid}} {{Use dmy dates|date=October 2019}} {{Infobox planet | minorplanet = yes | name = 1075 Helina | background = #D6D6D6 | image = 001075-asteroid shape model (1075) Helina.png | image_scale = | caption = Modelled shape of ''Helina'' from its lightcurve | discovery_ref = <ref name="jpldata" /> | discoverer = G. Neujmin | discovery_site = Simeiz Obs. | discovered = 29 September 1926 | mpc_name = (1075) Helina | alt_names = 1926 SC{{·}}1930 KV 1965 CB{{·}}A906 YG A916 WH | pronounced = | named_after = Helij Neujmin<ref name="springer" /> {{small|(discoverer's son)}} | mp_category = main-belt{{·}}{{small|(outer)}} Eos<ref name="lcdb" /><ref name="Ferret" /> | orbit_ref = <ref name="jpldata" /> | epoch = 4 September 2017 (JD 2458000.5) | uncertainty = 0 | observation_arc = 110.85 yr (40,489 days) | aphelion = 3.3528 AU | perihelion = 2.6705 AU | semimajor = 3.0116 AU | eccentricity = 0.1133 | period = 5.23 yr (1,909 days) | mean_anomaly = 156.59° | mean_motion = {{Deg2DMS|0.1886|sup=ms}} / day | inclination = 11.523° | asc_node = 100.81° | arg_peri = 250.61° | mean_diameter = {{val|26.198|0.414}} km<ref name="Masiero-2012" /> {{val|30.39|7.76}} km<ref name="Nugent-2016" /> {{val|34.48|0.58}} km<ref name="Masiero-2012" /> 35.52 km<ref name="lcdb" /><ref name="SIMPS" /> {{val|37.93|0.85}} km<ref name="AKARI" /> | rotation = {{val|44.554|0.1526}} h<ref name="Waszczak-2015" /> {{val|44.6768|0.0001}} h<ref name="Durech-2016" /> {{val|44.6770|0.0002}} h{{efn|name=Hanus-2016d}} {{val|44.677|0.001}} h<ref name="Hanus-2018" /> {{val|44.9|0.1}} h<ref name="geneva-obs" /> | pole_ecliptic_lat= {{plainlist| * (127.0°, −43.0.0°) (λ1/β1)<ref name="Ferret" /> * (280.0°, −44.0°) (λ2/β2)<ref name="Ferret" />}} | albedo = {{val|0.11|0.07}}<ref name="Nugent-2016" /> {{val|0.111|0.005}}<ref name="AKARI" /> 0.1220<ref name="lcdb" /><ref name="SIMPS" /> {{val|0.129|0.009}}<ref name="Masiero-2012" /> | spectral_type = Tholen {{=}} SU<ref name="jpldata" /><ref name="lcdb" /> B–V {{=}} 0.765<ref name="jpldata" /> U–B {{=}} 0.370<ref name="jpldata" /> | abs_magnitude = {{val|10.10|0.43}}<ref name="Veres-2015" />{{·}}10.15<ref name="jpldata" /><ref name="lcdb" /><ref name="Masiero-2012" /><ref name="SIMPS" /><ref name="AKARI" />{{·}}10.31<ref name="Nugent-2016" />{{·}}{{val|10.371|0.003}} {{small|(R)}}<ref name="Waszczak-2015" /> }}

'''1075 Helina''', provisional designation {{mp|1926 SC}}, is a stony Eos asteroid from the outer regions of the asteroid belt, approximately {{convert|34|km|mi|abbr=off|sp=us}} in diameter. It was discovered on 29 September 1926, by astronomer Grigory Neujmin at the Simeiz Observatory on the Crimean peninsula.<ref name="MPC-object" /> The asteroid was named after the discoverer's son, Helij Neujmin.<ref name="springer" />

== Orbit and classification ==

''Helina'' is a member the Eos family ({{small|606}}),<ref name="lcdb" /><ref name="Ferret" /> the largest asteroid family of the outer main belt consisting of nearly 10,000 asteroids.<ref name="Nesvorny-2014" />{{rp|23}} It orbits the Sun in the outer asteroid belt at a distance of 2.7–3.4 AU once every 5 years and 3 months (1,909 days; semi-major axis of 3.01 AU). Its orbit has an eccentricity of 0.11 and an inclination of 12° with respect to the ecliptic.<ref name="jpldata" />

The asteroid was first identified as {{mp|A906 YG}} at Heidelberg Observatory in December 1906. The body's observation arc begins at Simeiz Observatory in October 1926, nine days after its official discovery observation.<ref name="MPC-object" />

== Naming ==

This minor planet was named after Helij Grigorevich Neujmin (1910–1982), a son of discoverer Grigory Neujmin. The author of the ''Dictionary of Minor Planet Names'', Lutz Schmadel learned about the naming circumstances from Crimean astronomers I. I. Neyachenko and N. S. Chernykh ''(see 2325 Chernykh)''.<ref name="springer" />

== Physical characteristics ==

In the Tholen classification, ''Helina'' is a stony S-type asteroid with an unusual spectra (SU).<ref name="jpldata" /><ref name="lcdb" />

=== Rotation period ===

In March 2013, a rotational lightcurve of ''Helina'' was obtained from photometric observations in the R-band by astronomers at the Palomar Transient Factory in California. Lightcurve analysis gave a rotation period of 44.554 hours with a brightness variation of 0.91 magnitude ({{small|U=2}}).<ref name="Waszczak-2015" /> In April 2013, European amateur astronomers Matthieu Bachschmidt, Paul Krafft, Olivier Gerteis, Hubert Gully and Luc Arnold measured a period of 44.9 hours with an amplitude of 0.64 magnitude ({{small|U=3-}}).<ref name="geneva-obs" />

While not being a slow rotator, ''Helina'' has a longer-than average period. Its high brightness amplitude is also indicative for an elongated or irregular shape, rather than a spherical one.

=== Poles ===

The asteroid's lightcurve has also been modeled several times. It gave a concurring period of 44.6768 and 44.677 hours, respectively.<ref name="Durech-2016" /><ref name="Hanus-2018" />{{efn|name=Hanus-2016d}} Modelling in the 2018-study also gave two spin axis of (127.0°, −43.0.0°) and (280.0°, −44.0°) in ecliptic coordinates (λ, β).<ref name="Hanus-2018" />

=== Diameter and albedo ===

According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite and the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, ''Helina'' measures between 26.198 and 37.93 kilometers in diameter and its surface has an albedo between 0.11 and 0.129.<ref name="Masiero-2012" /><ref name="Nugent-2016" /><ref name="SIMPS" /><ref name="AKARI" /> The ''Collaborative Asteroid Lightcurve Link'' adopts the results obtained by IRAS, that is an albedo of 0.1220 and a diameter of 35.52 kilometers based on an absolute magnitude of 10.15.<ref name="lcdb" /><ref name="SIMPS" />

== Notes == {{notelist|refs=

{{efn|name=Hanus-2016d|1=Hanus (2016d) publication not indexed in ADS. Summary figures for (1075) Helina at [http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=1075%7CHelina LCDB]}}

}}

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

<ref name="jpldata">{{cite web |type = 2017-10-30 last obs. |title = JPL Small-Body Database Browser: 1075 Helina (1926 SC) |url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2001075 |publisher = Jet Propulsion Laboratory |accessdate = 6 December 2017}}</ref>

<ref name="springer">{{cite book |last = Schmadel | first = Lutz D. |title = Dictionary of Minor Planet Names |publisher = Springer Berlin Heidelberg |chapter = (1075) Helina |page = 92 |date = 2007 |isbn = 978-3-540-00238-3 |doi = 10.1007/978-3-540-29925-7_1076}}</ref>

<ref name="MPC-object">{{cite web |title = 1075 Helina (1926 SC) |work = Minor Planet Center |url = https://www.minorplanetcenter.net/db_search/show_object?object_id=1075 |accessdate = 6 December 2017}}</ref>

<ref name="geneva-obs">{{cite web |title = Asteroids and comets rotation curves – (1075) Helina |last = Behrend |first = Raoul |publisher = Geneva Observatory |url = http://obswww.unige.ch/~behrend/page3cou.html#001075 |accessdate = 6 December 2017}}</ref>

<ref name="SIMPS">{{cite journal |first1 = E. F. |last1 = Tedesco |first2 = P. V. |last2 = Noah |first3 = M. |last3 = Noah |first4 = S. D. |last4 = Price |date = October 2004 |title = IRAS Minor Planet Survey V6.0 |url = https://sbnarchive.psi.edu/pds3/iras/IRAS_A_FPA_3_RDR_IMPS_V6_0/data/diamalb.tab |journal = NASA Planetary Data System |volume = 12 |pages = IRAS-A-FPA-3-RDR-IMPS-V6.0 |bibcode = 2004PDSS...12.....T |accessdate = 22 October 2019}}</ref>

<ref name="Ferret">{{cite web |title = Asteroid 1075 Helina – Nesvorny HCM Asteroid Families V3.0 |work = Small Bodies Data Ferret |url = https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=1075+Helina#Asteroid%201075%20HelinaEAR-A-VARGBDET-5-NESVORNYFAM-V3.0 |accessdate = 26 October 2019}}</ref>

<ref name="Nesvorny-2014">{{Cite book |first1 = D. |last1 = Nesvorný |first2 = M. |last2 = Broz |first3 = V. |last3 = Carruba |date = December 2014 |chapter = Identification and Dynamical Properties of Asteroid Families |title = Asteroids IV |pages = 297–321 |bibcode = 2015aste.book..297N |doi = 10.2458/azu_uapress_9780816532131-ch016 |arxiv = 1502.01628 |isbn = 9780816532131}}</ref>

<ref name="lcdb">{{cite LCDB|number = 1075 |accessdate = 6 December 2017}}</ref>

<ref name="Masiero-2012">{{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 = C. |last6 = Nugent |first7 = M. S. |last7 = Cabrera |date = November 2012 |title = Preliminary Analysis of WISE/NEOWISE 3-Band Cryogenic and Post-cryogenic Observations of Main Belt Asteroids |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012ApJ...759L...8M |journal = The Astrophysical Journal Letters |volume = 759 |issue = 1 |page = 5 |bibcode = 2012ApJ...759L...8M |doi = 10.1088/2041-8205/759/1/L8 |arxiv = 1209.5794 |access-date= 6 December 2017}}</ref>

<ref name="Nugent-2016">{{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 }}</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= free }} ([http://vizier.cfa.harvard.edu/viz-bin/VizieR-5?-source=J/PASJ/63/1117/acua_v1&Num=1075 online], [https://core.ac.uk/download/pdf/43545172.pdf AcuA catalog p. 153])</ref>

<ref name="Waszczak-2015">{{cite journal |display-authors = 6 |first1 = Adam |last1 = Waszczak |first2 = Chan-Kao |last2 = Chang |first3 = Eran O. |last3 = Ofek |first4 = Russ |last4 = Laher |first5 = Frank |last5 = Masci |first6 = David |last6 = Levitan |first7 = Jason |last7 = Surace |first8 = Yu-Chi |last8 = Cheng |first9 = Wing-Huen |last9 = Ip |first10 = Daisuke |last10 = Kinoshita |first11 = George |last11 = Helou |first12 = Thomas A. |last12 = Prince |first13 = Shrinivas |last13 = Kulkarni |date = September 2015 |title = Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015AJ....150...75W |journal = The Astronomical Journal |volume = 150 |issue = 3 |page = 35 |bibcode = 2015AJ....150...75W |doi = 10.1088/0004-6256/150/3/75 |arxiv = 1504.04041 |access-date= 6 December 2017}}</ref>

<ref name="Durech-2016">{{cite journal |first1 = J. |last1 = Durech |first2 = J. |last2 = Hanus |first3 = D. |last3 = Oszkiewicz |first4 = R. |last4 = Vanco |date = March 2016 |title = Asteroid models from the Lowell photometric database |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2016A&A...587A..48D |journal = Astronomy and Astrophysics |volume = 587 |page = 6 |bibcode = 2016A&A...587A..48D |doi = 10.1051/0004-6361/201527573 |arxiv = 1601.02909 |access-date= 6 December 2017}}</ref>

<ref name="Hanus-2018">{{Cite journal |display-authors = 6 |first1 = J. |last1 = Hanus |first2 = M. |last2 = Delbo' |first3 = V. |last3 = Alí-Lagoa |first4 = B. |last4 = Bolin |first5 = R. |last5 = Jedicke |first6 = J. |last6 = Durech |first7 = H. |last7 = Cibulková |first8 = P. |last8 = Pravec |first9 = P. |last9 = Kusnirák |first10 = R. |last10 = Behrend |first11 = F. |last11 = Marchis |first12 = P. |last12 = Antonini |first13 = L. |last13 = Arnold |first14 = M. |last14 = Audejean |first15 = M. |last15 = Bachschmidt |first16 = L. |last16 = Bernasconi |first17 = L. |last17 = Brunetto |first18 = S. |last18 = Casulli |first19 = R. |last19 = Dymock |first20 = N. |last20 = Esseiva |first21 = M. |last21 = Esteban |first22 = O. |last22 = Gerteis |first23 = H. |last23 = de Groot |first24 = H. |last24 = Gully |first25 = Hiroko |last25 = Hamanowa |first26 = Hiromi |last26 = Hamanowa |first27 = P. |last27 = Krafft |first28 = M. |last28 = Lehký |first29 = F. |last29 = Manzini |first30 = J. |last30 = Michelet |first31 = E. |last31 = Morelle |first32 = J. |last32 = Oey |first33 = F. |last33 = Pilcher |first34 = F. |last34 = Reignier |first35 = R. |last35 = Roy |first36 = P. A. |last36 = Salom |first37 = B. D. |last37 = Warner |date = January 2018 |title = Spin states of asteroids in the Eos collisional family |journal = Icarus |volume = 299 |pages = 84–96 |bibcode = 2018Icar..299...84H |doi = 10.1016/j.icarus.2017.07.007 |arxiv = 1707.05507}}</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 - 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 |access-date= 6 December 2017}}</ref>

}}

== 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 * [https://www.minorplanetcenter.net/iau/lists/NumberedMPs000001.html Discovery Circumstances: Numbered Minor Planets (1)-(5000)] – Minor Planet Center * {{AstDys|1075}} * {{JPL small body}}

{{Minor planets navigator |1074 Beljawskya |number=1075 |1076 Viola}} {{Small Solar System bodies}} {{Authority control}}

{{DEFAULTSORT:Helina}} 001075 Category:Discoveries by Grigory Neujmin Category:Named minor planets 001075 19260929