{{Short description|Stony main-belt asteroid}} {{Use dmy dates|date=October 2019}} {{Infobox planet | minorplanet = yes | name = 1938 Lausanna | background = #D6D6D6 | image = | image_size = | caption = | discovery_ref = <ref name="jpldata" /> | discovered = 19 April 1974 | discoverer = P. Wild | discovery_site = Zimmerwald Obs. | mpc_name = (1938) Lausanna | alt_names = 1974 HC{{·}}1934 KA<br />1947 DB{{·}}1950 CO<br />1955 VK{{·}}1957 EH<br />{{mp|1962 WB|1}}{{·}}{{mp|1967 ED|1}}<br />1971 OX{{·}}{{mp|1972 XY|1}} | pronounced = | named_after = Lausanne {{small|(Swiss city)}}<ref name="springer" /> | mp_category = main-belt{{·}}Flora<ref name="lcdb" /> | orbit_ref = <ref name="jpldata" /> | epoch = 4 September 2017 (JD 2458000.5) | uncertainty = 0 | observation_arc = 82.99 yr (30,312 days) | aphelion = 2.5938 AU | perihelion = 1.8796 AU | semimajor = 2.2367 AU | eccentricity = 0.1597 | period = 3.35 yr (1,222 days) | mean_anomaly = 329.17° | mean_motion = {{Deg2DMS|0.2946|sup=ms}} / day | inclination = 3.3343° | asc_node = 171.69° | arg_peri = 64.830° | dimensions = {{val|7.638|0.124}} km<ref name="Masiero-2014" /><br />7.82 km {{small|(calculated)}}<ref name="lcdb" /><br />{{val|8.214|0.077}} km<ref name="WISE" /> | rotation = {{val|2.748|0.001}} h{{efn|name=LCDB-Skiff-2014}}<br />{{val|2.748|0.001}} h<ref name="Warell-2015b" /> | albedo = {{val|0.1660|0.0301}}<ref name="WISE" /><br />{{val|0.192|0.055}}<ref name="Masiero-2014" /><br />0.24 {{small|(assumed)}}<ref name="lcdb" /> | spectral_type = S<ref name="lcdb" /><ref name="Veres-2015" /> | abs_magnitude = {{val|12.60|0.26}}<ref name="Veres-2015" />{{·}}12.7<ref name="jpldata" /><ref name="lcdb" />{{·}}13.0<ref name="WISE" /> }}
'''1938 Lausanna''', provisional designation {{mp|1974 HC}}, is a stony Florian asteroid from the inner regions of the asteroid belt. It is approximately 8 kilometers in diameter, and was discovered on 19 April 1974 by Swiss astronomer, Paul Wild at Zimmerwald Observatory near Bern, Switzerland.<ref name="MPC-Lausanna" /> It is named for the city of Lausanne.<ref name="springer" />
== Orbit and classification ==
Lausanna is a S-type asteroid and member of the Flora family, one of the largest collisional populations of stony asteroids in the main-belt. It orbits the Sun in the inner main-belt at a distance of 1.9–2.6 AU once every 3 years and 4 months (1,222 days). Its orbit has an eccentricity of 0.16 and an inclination of 3° with respect to the ecliptic.<ref name="jpldata" /> It was first identified as {{mp|1934 KA}} at Johannesburg Observatory in 1934, extending the body's observation arc by 40 years prior to its official discovery observation at Zimmerwald.<ref name="MPC-Lausanna" />
== Physical characteristics ==
=== Rotation period ===
In March 2014, two rotational lightcurves of Lausanna were obtained from photometric observations by American astronomer Brian Skiff and by Johan Warell at Lindby Observatory ({{small|K60}}) in Sweden. Lightcurve analysis gave an identical rotation period of 2.748 hours with a brightness amplitude of 0.13 and 0.12 magnitude, respectively ({{small|U=3-/2}}).{{efn|name=LCDB-Skiff-2014}}<ref name="Warell-2015b" /> The short period is near the threshold of 2.2 hours for fast rotating asteroids.
=== Diameter and albedo ===
According to the space-based survey carried out by NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Lausanna measures 7.64 and 8.21 kilometers in diameter, and its surface has an albedo of 0.166 and 0.192, respectively.<ref name="Masiero-2014" /><ref name="WISE" /> The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, the largest member and namesake of its family – and calculates a diameter of 7.82 kilometers based on an absolute magnitude of 12.7.<ref name="lcdb" />
== Naming ==
This minor planet was named for the Swiss city of Lausanne, located in the French-speaking part of the country. The discoverer Paul Wild, known for his unconventional minor-planet namings, discovered three more asteroids during winter of 1973/74. He named these 1935 Lucerna, 1936 Lugano and 1937 Locarno, after the Swiss cities Lucerne, Lugano and Locarno, respectively, hence composing an alliterated quartet of sequentially numbered, thematically named minor planets. The official {{MoMP|1938|naming citation}} was published by the Minor Planet Center on 1 April 1978 ({{small|M.P.C. 4358}}).<ref name="DoMP-Circular-dates" />
== Notes == {{notelist|refs=
{{efn|name=LCDB-Skiff-2014|1=Skiff (2014) web: rotation period {{val|2.748|0.001}} hours with a brightness amplitude of {{val|0.13}} mag and a Quality Code of 3-. Summary figures at [http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=1938%7CLausanna Collaborative Asteroid Lightcurve Link (CALL) for (1938) Lausanna]}}
}} <!-- end of notelist -->
== References == {{reflist|30em|refs=
<ref name="jpldata">{{cite web |type = 2017-05-06 last obs. |title = JPL Small-Body Database Browser: 1938 Lausanna (1974 HC) |url = https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2001938 |publisher = Jet Propulsion Laboratory |accessdate = 10 June 2017}}</ref>
<ref name="springer">{{cite book |title = Dictionary of Minor Planet Names – (1938) Lausanna |last = Schmadel | first = Lutz D. |publisher = Springer Berlin Heidelberg |page = 155 |date = 2007 |isbn = 978-3-540-00238-3 |doi = 10.1007/978-3-540-29925-7_1939 |chapter = (1938) Lausanna }}</ref>
<ref name="MPC-Lausanna">{{cite web |title = 1938 Lausanna (1974 HC) |work = Minor Planet Center |url = https://www.minorplanetcenter.net/db_search/show_object?object_id=1938 |accessdate = 26 January 2017}}</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}}</ref>
<ref name="Masiero-2014">{{cite journal |display-authors = 6 |first1 = Joseph R. |last1 = Masiero |first2 = T. |last2 = Grav |first3 = A. K. |last3 = Mainzer |first4 = C. R. |last4 = Nugent |first5 = J. M. |last5 = Bauer |first6 = R. |last6 = Stevenson |first7 = S. |last7 = Sonnett |date = August 2014 |title = Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2014ApJ...791..121M |journal = The Astrophysical Journal |volume = 791 |issue = 2 |page = 11 |bibcode = 2014ApJ...791..121M |doi = 10.1088/0004-637X/791/2/121 |arxiv = 1406.6645 |access-date= 26 January 2017}}</ref>
<ref name="lcdb">{{cite LCDB|number = 1938 |accessdate = 26 January 2017}}</ref>
<ref name="WISE">{{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}}</ref>
<ref name="Warell-2015b">{{Cite journal |first1 = Johan |last1 = Warell |first2 = Riccardo |last2 = Pappini |date = January 2015 |title = Rotational Period of 1938 Lausanna |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2015MPBu...42...20W |journal = The Minor Planet Bulletin |volume = 42 |issue = 1 |pages = 20–21 |issn = 1052-8091 |bibcode = 2015MPBu...42...20W |access-date= 26 January 2017}}</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= 26 January 2017}}</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/20110721225144/http://www.minorplanet.info/lightcurvedatabase.html |date=21 July 2011 }}) * [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 * [https://www.minorplanetcenter.net/iau/lists/NumberedMPs000001.html Discovery Circumstances: Numbered Minor Planets (1)-(5000)] – Minor Planet Center * {{AstDys|1938}} * {{JPL small body}}
{{Minor planets navigator |1937 Locarno |number=1938 |1939 Loretta}} {{Small Solar System bodies}} {{Authority control}}
{{DEFAULTSORT:Lausanna}} 001938 Category:Discoveries by Paul Wild (Swiss astronomer) Category:Named minor planets 001938 19740419