930 Westphalia

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930 Westphalia
Discovery  [1]
Discovered by W. Baade
Discovery site Bergedorf Obs.
Discovery date10 March 1920
Designations
(930) Westphalia
Pronunciation /wɛstˈfeɪliə/ [2]
Named after
 Westphalia
(German region) [3]
A920 EE ·1920 GS
A916 DD ·1916 DD
main-belt   [1] [4]  ·(inner)
background   [5] [6]  · slow   [6] [7]
Orbital characteristics   [4]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc 99.58 yr (36,370 d)
Aphelion 2.7792 AU
Perihelion 2.0828 AU
2.4310 AU
Eccentricity 0.1432
3.79 yr (1,384 d)
32.395°
0° 15m 36s / day
Inclination 15.336°
340.94°
329.98°
Physical characteristics
Mean diameter
  • 34.922±0.153  km [8]
  • 36.48±1.4 km [9]
  • 39.51±1.47 km [10]
100.66±0.12  h [7] [11]
  • 0.031±0.002 [10]
  • 0.0366±0.003 [9]
  • 0.040±0.007 [8]
SMASS = Ch   [4]

    930 Westphalia (prov. designation: A920 EEor1920 GS) is a very dark background asteroid and a slow rotator from the inner regions of the asteroid belt, that measures approximately 36 kilometers (22 miles) in diameter. It was discovered on 10 March 1920, by German astronomer Walter Baade at the Bergedorf Observatory in Hamburg. [1] The carbonaceous C-type asteroid (Ch) has an exceptionally long rotation period of 100.7 hours and is likely spherical in shape. It was named after Westphalia, a region in northwestern Germany. [3]

    Contents

    Orbit and classification

    Westphalia is a non-family asteroid of the main belt's background population when applying the hierarchical clustering method to its proper orbital elements. [5] [6] It orbits the Sun in the inner asteroid belt at a distance of 2.1–2.8  AU once every 3 years and 9 months (1,384 days; semi-major axis of 2.43 AU). Its orbit has an eccentricity of 0.14 and an inclination of 15° with respect to the ecliptic. [4] The asteroid was first observed as A916 DD (1916 DD) at the Simeiz Observatory on 24 February 1916. The body's observation arc begins with its official discovery observation at Bergedorf Observatory on 10 March 1920. [1]

    Naming

    This minor planet was named after the region of Westphalia in northwestern Germany, bordering the Netherlands and the Rhine river. It is the birthplace of the discoverer Walter Baade (1893–1960). The naming was mentioned in The Names of the Minor Planets by Paul Herget in 1955 ( H 90 ). [3]

    Physical characteristics

    In the Bus–Binzel SMASS classification, Westphalia is a hydrated carbonaceous C-type asteroid (Ch). [4]

    Rotation period

    In April 2015, a rotational lightcurve of Westphalia was obtained from photometric observations by Eduardo Manuel Álvarez at the Los Algarrobos Observatory ( I38 ) in Uruguay. Lightcurve analysis gave a rotation period of 100.66±0.12 hours with a brightness amplitude of 0.15±0.02 magnitude, indicative of a spherical, non-elongated shape ( U=2 ). This was the first time a period could be determined for this asteroid, and, as the observer noted, there were only 18 tree-digit asteroids left for which no such measurement had yet been made. [11] With a period above 100 hours, Westphalia is a slow rotator. While the slowest rotators have periods above 1000 hours, the vast majority of asteroids have periods between 2.2 and 20 hours.

    Diameter and albedo

    According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer (WISE), the Infrared Astronomical Satellite IRAS, and the Japanese Akari satellite, Westphalia measures (34.922±0.153), (36.48±1.4) and (39.51±1.47) kilometers in diameter and its surface has a very low albedo of (0.040±0.007), (0.0366±0.003) and (0.031±0.002), respectively. [8] [9] [10]

    The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0438 and a diameter of 36.53 km based on an absolute magnitude of 11.2. [7] Further published mean-diameters and albedos by the WISE team in ascending order include (35.34±1.13 km), (35.602±0.157 km), (35.896±10.36 km), (38.107±12.56 km), (38.502±10.778 km) and (44.522±0.240 km) and albedos of (0.031±0.021), (0.0312±0.0240), (0.032±0.001), (0.0373±0.0253), (0.0384±0.0059) and (0.04±0.01). [6] [7]

    Related Research Articles

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    835 Olivia is a dark background asteroid from the outer regions of the asteroid belt. It was discovered by German astronomer Max Wolf at the Heidelberg-Königstuhl State Observatory on 23 September 1916. The carbonaceous C-type asteroid measures approximately 35 kilometers in diameter, and is one of few low-numbered asteroids with an undetermined rotation period. Any reference to the origin of the asteroid's name is unknown.

    869 Mellena is a dark background asteroid from the central region of the asteroid belt. It was discovered on 9 May 1917, by astronomer Richard Schorr at the Bergedorf Observatory in Hamburg. The carbonaceous C-type asteroid has a shorter than average rotation period of 6.5 hours and measures approximately 19 kilometers in diameter. It was named after Werner von Melle (1853–1937), mayor of Hamburg, who founded the discovering observatory.

    <span class="mw-page-title-main">928 Hildrun</span>

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    927 Ratisbona is a large and dark background asteroid, approximately 76 kilometers in diameter, located in the outer region of the asteroid belt. It was discovered on 16 February 1920, by astronomer Max Wolf at the Heidelberg Observatory in southwest Germany. The carbonaceous C-type asteroid (CB) has a rotation period of 12.99 hours and is rather spherical in shape. It was named after the Bavarian city of Regensburg.

    929 Algunde, is a stony Flora asteroid from the inner regions of the asteroid belt, that measures approximately 11 kilometers in diameter. It was discovered by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory on 10 March 1920. The S-type asteroid has a short rotation period of 3.3 hours and is likely spherical in shape. It was named "Algunde", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote.

    931 Whittemora is a metallic background asteroid, approximately 46 kilometers in diameter, located in the outer region of the asteroid belt. It was discovered by French astronomer François Gonnessiat at the Algiers Observatory in North Africa on 19 March 1920. The M-type asteroid has a rotation period of 19.2 hours. It was named after American archaeologist Thomas Whittemore (1871–1950).

    932 Hooveria is a dark background asteroid, approximately 59 kilometers in diameter, located in the inner region of the asteroid belt. It was discovered by Austrian astronomer Johann Palisa at the Vienna Observatory on 23 March 1920. The carbonaceous C-type asteroid (Ch) has a long rotation period of 78.4 hours. It was named after then-Secretary of Commerce Herbert Hoover (1874–1964), who later became president of the United States.

    938 Chlosinde is a carbonaceous Themistian asteroid, approximately 33 kilometers in diameter, from the outer regions of the asteroid belt. It was discovered by astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany on 9 September 1920. The C-type asteroid has an ambiguous rotation period of 13.7 or 19.2 hours. It was named "Chlosinde", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote.

    940 Kordula is a large and dark Cybele asteroid from the outermost region of the asteroid belt, approximately 80 kilometers in diameter. It was discovered on 10 October 1920, by astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in Germany. The carbonaceous F-type asteroid (FC) has a rotation period of 15.6 hours. It was named "Kordula", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote.

    941 Murray is a background asteroid, approximately 18 kilometers in diameter, located in the central region of the asteroid belt. It was discovered by Austrian astronomer Johann Palisa at the Vienna Observatory on 10 October 1920. The X-type asteroid has a short rotation period of 3.4 hours. It was named after British professor Gilbert Murray (1866–1957).

    942 Romilda is a background asteroid, approximately 36 kilometers in diameter, located in the outer region of the asteroid belt. It was discovered by German astronomer Karl Reinmuth at the Heidelberg Observatory on 11 October 1920. The assumed C-type asteroid has a rotation period of 6.97 hours. It was named "Romilda", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote.

    <span class="mw-page-title-main">943 Begonia</span>

    943 Begonia is a large, carbonaceous background asteroid, approximately 70 kilometers in diameter, from the outer region of the asteroid belt. It was discovered by German astronomer Karl Reinmuth at the Heidelberg Observatory on 20 October 1920 and given the provisional designations A920 UA and 1920 HX. The dark C-type asteroid (Ch) has a rotation period of 15.7 hours. It was named after the genus of popular houseplants, Begonia.

    959 Arne is a background asteroid and slow rotator, approximately 52 kilometers in diameter, located in the outer region of the asteroid belt. It was discovered by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory on 30 September 1921. The X-type asteroid has an exceptionally long rotation period of 123.7 hours. It was named after Arne Asplind, son of Swedish astronomer Bror Asplind (1890–1954).

    989 Schwassmannia is a stony background asteroid and a slow rotator from the central regions of the asteroid belt, approximately 12.5 kilometers in diameter. It was discovered on 18 November 1922, by astronomer Friedrich Karl Arnold Schwassmann at the Bergedorf Observatory in Hamburg, Germany. The bright S/T-type asteroid has a long rotation period of 107.9 hours. It was named after the discoverer himself.

    <span class="mw-page-title-main">934 Thüringia</span>

    934 Thüringia is a dark background asteroid, approximately 54 kilometers in diameter, located in the central region of the asteroid belt. It was discovered on 15 August 1920, by astronomer Walter Baade at the Bergedorf Observatory in Hamburg, Germany. The hydrated C-type asteroid has a rotation period of 8.2 hours and is likely irregular in shape. It was named after the German state of Thuringia. The naming was inspired by the ocean liner SS Thuringia.

    1240 Centenaria, provisional designation 1932 CD, is a background asteroid from the outer regions of the asteroid belt, approximately 60 kilometers in diameter. It was discovered on 5 February 1932, by astronomer Richard Schorr at the Bergedorf Observatory in Hamburg, Germany. The assumed C-type asteroid has a rotation period of 11.3 hours. It was named for the 100th anniversary of the discovering observatory.

    2140 Kemerovo, provisional designation 1970 PE, is a dark asteroid from the outer region of the asteroid belt, approximately 30 kilometers in diameter.

    1303 Luthera, provisional designation 1928 FP, is a dark asteroid and the parent body of the Luthera family, located in the outermost regions of the asteroid belt. It measures approximately 90 kilometers in diameter. The asteroid was discovered on 16 March 1928, by astronomer Friedrich Schwassmann at the Bergedorf Observatory in Hamburg, Germany, and later named after German astronomer Robert Luther.

    1426 Riviera, provisional designation 1937 GF, is a bright asteroid from the central regions of the asteroid belt, approximately 16 kilometers in diameter. Discovered by Marguerite Laugier at the Nice Observatory in 1937, the asteroid was later named for the Côte d'Azur, also known as French Riviera.

    References

    1. 1 2 3 4 5 "930 Westphalia (A920 EE)". Minor Planet Center. Retrieved 18 February 2020.
    2. ↑ Noah Webster (1884) A Practical Dictionary of the English Language
    3. 1 2 3 Schmadel, Lutz D. (2007). "(930) Westphalia". Dictionary of Minor Planet Names . Springer Berlin Heidelberg. pp.  82–83. doi:10.1007/978-3-540-29925-7_931. ISBN   978-3-540-00238-3.
    4. 1 2 3 4 5 6 "JPL Small-Body Database Browser: 930 Westphalia (A920 EE)" (2019-10-16 last obs.). Jet Propulsion Laboratory. Archived from the original on 19 September 2020. Retrieved 18 February 2020.
    5. 1 2 "Asteroid 930 Westphalia – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 18 February 2020.
    6. 1 2 3 4 "Asteroid 930 Westphalia". Small Bodies Data Ferret. Retrieved 18 February 2020.
    7. 1 2 3 4 "LCDB Data for (930) Westphalia". Asteroid Lightcurve Database (LCDB). Retrieved 18 February 2020.
    8. 1 2 3 Masiero, Joseph R.; Grav, T.; Mainzer, A. K.; Nugent, C. R.; Bauer, J. M.; Stevenson, R.; et al. (August 2014). "Main-belt Asteroids with WISE/NEOWISE: Near-infrared Albedos". The Astrophysical Journal. 791 (2): 11. arXiv: 1406.6645 . Bibcode:2014ApJ...791..121M. doi:10.1088/0004-637X/791/2/121.
    9. 1 2 3 Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System. 12: IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T . Retrieved 18 February 2020.
    10. 1 2 3 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)
    11. 1 2 Álvarez, Eduardo Manuel (July 2015). "Period Determination for the Slow Rotator 930 Westphalia" (PDF). The Minor Planet Bulletin. 42 (3): 212. Bibcode:2015MPBu...42..212A. Archived from the original (PDF) on 18 February 2020. Retrieved 18 February 2020.
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