926 Imhilde

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926 Imhilde
Discovery  [1]
Discovered by K. Reinmuth
Discovery site Heidelberg Obs.
Discovery date15 February 1920
Designations
(926) Imhilde
Named after
Name picked from the almanac
Lahrer Hinkender Bote   [2]
A920 CB ·1920 GN
1931 GB ·1964 WB
main-belt   [1] [3]  ·(outer)
Imhilde   [4]
Orbital characteristics   [3]
Epoch 31 May 2020 (JD 2459000.5)
Uncertainty parameter 0
Observation arc 99.70 yr (36,416 d)
Aphelion 3.5251 AU
Perihelion 2.4365 AU
2.9808 AU
Eccentricity 0.1826
5.15 yr (1,880 d)
97.231°
0° 11m 29.4s / day
Inclination 16.325°
48.971°
173.79°
Physical characteristics
Mean diameter
  • 46.369±1.133  km [5]
  • 48.48±1.1 km [6]
  • 49.87±0.92 km [7]
26.8±0.5  h [8] [lower-alpha 1]
  • 0.052±0.007 [5]
  • 0.054±0.002 [7]
  • 0.0570±0.003 [6]
C (SDSS-MOC) [9]
10.5 [1] [3]

    926 Imhilde (prov. designation: A920 CBor1920 GN) is a dark asteroid and the principal body and namesake of the Imhilde family, located in the outer regions of the asteroid belt. It was discovered by astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany on 15 February 1920. [1] The carbonaceous C-type asteroid has a rotation period of 26.8 hours and measures approximately 48 kilometers (30 miles) in diameter. It was named "Imhilde", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote . [2]

    Contents

    Orbit and classification

    When applying the synthetic hierarchical clustering method (HCM) by Nesvorný, Imhilde is the principal body and namesake of the Imhilde family ( 639 ), a small asteroid cluster with only a few dozens members. [4] [10] : 23  However, according to another HCM-analysis by Milani and Knežević (AstDys), it is a background asteroid as the analysis does not recognize this family. [11] Imhilde orbits the Sun in the outer asteroid belt at a distance of 2.4–3.5  AU once every 5 years and 2 months (1,880 days; semi-major axis of 2.98 AU). Its orbit has an eccentricity of 0.18 and an inclination of 16° with respect to the ecliptic. [3] The body's observation arc begins at Heidelberg Observatory on 17 February 1920, two nights after its official discovery observation. [1]

    Naming

    This minor planet was named "Imhilde", after a female name picked from the Lahrer Hinkender Bote , published in Lahr, southern Germany. [2] A Hinkender Bote (lit. "limping messenger") was a very popular almanac, [12] especially in the alemannic-speaking region from the late 17th throughout the early 20th century. The calendar section contains feast days, the dates of important fairs and astronomical ephemerides. For 15 May, the calendar gives "Imhilde" as the German name day analogue next to Sophie and Torquatus, the protestant and catholic entries in the calendar of saints, likely referring to Sophia of Rome and Torquatus of Acci. [13]

    Reinmuth's calendar names

    As with 22 other asteroids – starting with 913 Otila, and ending with 1144 Oda – Reinmuth selected names from this calendar due to his many asteroid discoveries that he had trouble thinking of proper names. These names are not related to the discoverer's contemporaries. Lutz Schmadel, the author of the Dictionary of Minor Planet Names learned about Reinmuth's source of inspiration from private communications with Dutch astronomer Ingrid van Houten-Groeneveld, who worked as a young astronomer at Heidelberg. [2]

    Physical characteristics

    In the SDSS-based taxonomy, Imhilde is a carbonaceous C-type asteroid. [9] [14] The Imhilde family's overall spectral type is CX. [10] : 23 

    Rotation period

    In April 2003, a rotational lightcurve of Imhilde was obtained from photometric observations by Brian Warner at the Palmer Divide Observatory ( 716 ) in Colorado. In 2011, after more than a decade of additional experience in asteroid lightcurve photometry, Warner reexamined the data set using improved tools and techniques. Lightcurve analysis gave a rotation period of 26.8±0.5 hours with a brightness variation of 0.27±0.02 magnitude ( U=2 ). [8] [lower-alpha 1] Originally, the same data gave a period of 26.1±0.5 hours with an amplitude 0.2±0.02 magnitude ( U=2 ). [15]

    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, Imhilde measures (46.369±1.133), (48.48±1.1) and (49.87±0.92) kilometers in diameter and its surface has a low albedo of (0.052±0.007), (0.0570±0.003) and (0.054±0.002), respectively. [5] [6] [7]

    The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0476 and a diameter of 48.39 km based on an absolute magnitude of 10.5. [16] Further published mean-diameters and albedos by the WISE team include (44.148±10.193 km) and (46.37±1.13 km) and albedos of (0.055±0.020) and (0.052±0.007). [14] [16] An asteroid occultation observed on 8 November 2011, gave a best-fit ellipse dimension of 49.0 × 49.0 kilometers. [14] These timed observations are taken when the asteroid passes in front of a distant star. However the quality of the measurement is rated poorly. [14]

    Notes

    1. 1 2 Lightcurve plot of (926) Imhilde, Palmer Divide Observatory, Brian Warner (2003): rotation period 26.8±0.5 hours with a brightness amplitude of 0.27±0.02 mag. Quality code of 2. Summary figures for at the LCDB.

    Related Research Articles

    913 Otila is a bright Flora asteroid from the inner regions of the asteroid belt. It was discovered by German astronomer Karl Reinmuth at the Heidelberg Observatory on 19 May 1919. The stony S-type asteroid has a short rotation period of 4.9 hours and measures approximately 12 kilometers in diameter. It was named after 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">918 Itha</span> Main-belt asteroid

    918 Itha is a stony asteroid and the namesake as well as the principal body of the Itha family, located in the outer region of the asteroid belt. It was discovered by German astronomer Karl Reinmuth at the Heidelberg Observatory on 22 August 1919. The S-type asteroid has a notably short rotation period of only 3.5 hours and measures approximately 21 kilometers in diameter. It was named "Itha", a female name taken from the almanac Lahrer Hinkender Bote, unrelated to the discoverer's contemporaries.

    <span class="mw-page-title-main">920 Rogeria</span>

    920 Rogeria is a dark background asteroid from the central region of the asteroid belt, discovered by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory on 1 September 1919. The D-type asteroid (DT) has a rotation period of 12.2 hours and measures approximately 26 kilometers in diameter. It was named "Rogeria", a name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote.

    921 Jovita is a dark background asteroid, approximately 58 kilometers in diameter, located in the outer regions of the asteroid belt. It was discovered on 4 September 1919, by astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in southwest Germany. The carbonaceous C-type asteroid (Ch) has a rotation period of 15.6 hours and is likely spherical in shape. It was named "Jovita", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote.

    923 Herluga is a three-body resonant background asteroid, approximately 34 kilometers in diameter, located in the central region of the asteroid belt. It was discovered on 30 September 1919, by astronomer Karl Reinmuth at the Heidelberg Observatory in southwest Germany. The carbonaceous C-type asteroid has a rotation period of 19.7 hours. It was named "Herluga", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote.

    924 Toni is a large background asteroid, approximately 80 kilometers in diameter, from the outer regions of the asteroid belt. It was discovered on 20 October 1919, by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory. The X-type asteroid has a rotation period of 19.4 hours. It was named "Toni", 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">928 Hildrun</span>

    928 Hildrun, is a dark background asteroid, approximately 64 kilometers in diameter, located in the outer region of the asteroid belt. It was discovered on 23 February 1920, by astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in southwest Germany. The X-type asteroid has a rotation period of 14.1 hours. It was named "Hildrun", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote.

    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).

    <span class="mw-page-title-main">936 Kunigunde</span>

    936 Kunigunde is a dark Themistian asteroid from the outer regions of the asteroid belt, approximately 40 kilometers in diameter. It was discovered on 8 September 1920, by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory. The carbonaceous B-type asteroid has a rotation period of 9.4 hours. It was named "Kunigunde", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote.

    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.

    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.

    948 Jucunda is a background asteroid, approximately 17 kilometers in diameter, located in the outer region of the asteroid belt. It was discovered on 3 March 1921, by astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in southwest Germany. The asteroid has a longer-than average rotation period of 26.2 hours. It was named after 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">983 Gunila</span> Main-belt asteroid

    983 Gunila, is a dark background asteroid from the outer regions of the asteroid belt, approximately 74 kilometers in diameter. It was discovered on 30 July 1922, by astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in Germany. The X-type asteroid has an ambiguous rotation period of 8.3 or 16.6 hours. It was named "Gunila", a common German female name unrelated to the discoverer's contemporaries, that was taken from the almanac Lahrer Hinkender Bote.

    987 Wallia is a large background asteroid from the outer regions of the asteroid belt, approximately 52 kilometers in diameter. It was discovered on 23 October 1922, by astronomer Karl Reinmuth at the Heidelberg Observatory in southern Germany. The D/T-type asteroid has a rotation period of 10.1 hours and shows an unusual trinomial lightcurve. It was named after a common German female name, unrelated to the discoverer's contemporaries, and taken from the almanac Lahrer Hinkender Bote.

    <span class="mw-page-title-main">994 Otthild</span>

    994 Otthild is a stony background asteroid from the central regions of the asteroid belt, approximately 24 kilometers in diameter. It was discovered on 18 March 1923, by astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory. The S-type asteroid has a rotation period of 5.95 hours and is rather regular in shape. It was named after a common German female name, unrelated to the discoverer's contemporaries, and taken from the almanac Lahrer Hinkender Bote.

    <span class="mw-page-title-main">1419 Danzig</span>

    1419 Danzig is a highly elongated Flora asteroid from the inner regions of the asteroid belt. It was discovered on 5 September 1929, by German astronomer Karl Reinmuth at Heidelberg Observatory in southwest Germany. The stony S-type asteroid has a rotation period of 8.1 hours and measures approximately 14 kilometers in diameter. It was named for the city of Gdańsk.

    1174 Marmara, provisional designation 1930 UC, is a stony Eoan asteroid from the outer regions of the asteroid belt, approximately 17 kilometers in diameter. It was discovered on 17 October 1930, by German astronomer Karl Reinmuth at Heidelberg Observatory in southwest Germany. The asteroid was later named after the Sea of Marmara, located between Europe and Asia.

    <span class="mw-page-title-main">1249 Rutherfordia</span> Asteroid

    1249 Rutherfordia, provisional designation 1932 VB, is an elongated, stony Florian asteroid from the inner regions of the asteroid belt, approximately 13 kilometers in diameter. Discovered by Karl Reinmuth at Heidelberg Observatory in 1932, the asteroid was named after Rutherford, New Jersey a suburb of New York City, United States.

    References

    1. 1 2 3 4 5 "926 Imhilde (A920 CB)". Minor Planet Center. Retrieved 20 February 2020.
    2. 1 2 3 4 Schmadel, Lutz D. (2007). "(926) Imhilde". Dictionary of Minor Planet Names . Springer Berlin Heidelberg. p.  82. doi:10.1007/978-3-540-29925-7_927. ISBN   978-3-540-00238-3.
    3. 1 2 3 4 "JPL Small-Body Database Browser: 926 Imhilde (A920 CB)" (2019-10-29 last obs.). Jet Propulsion Laboratory . Retrieved 20 February 2020.
    4. 1 2 "Asteroid 926 Imhilde – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. Retrieved 20 February 2020.
    5. 1 2 3 Mainzer, A. K.; Bauer, J. M.; Cutri, R. M.; Grav, T.; Kramer, E. A.; Masiero, J. R.; et al. (June 2016). "NEOWISE Diameters and Albedos V1.0". NASA Planetary Data System: EAR-A-COMPIL-5-NEOWISEDIAM-V1.0. Bibcode:2016PDSS..247.....M.
    6. 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 20 February 2020.
    7. 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)
    8. 1 2 Warner, Brian D. (April 2011). "Upon Further Review: VI. An Examination of Previous Lightcurve Analysis from the Palmer Divide Observatory" (PDF). Minor Planet Bulletin. 38 (2): 96–101. Bibcode:2011MPBu...38...96W. ISSN   1052-8091. Archived from the original (PDF) on 20 February 2020. Retrieved 20 February 2020.
    9. 1 2 Carvano, J. M.; Hasselmann, P. H.; Lazzaro, D.; Mothé-Diniz, T. (February 2010). "SDSS-based taxonomic classification and orbital distribution of main belt asteroids". Astronomy and Astrophysics. 510: 12. Bibcode:2010A&A...510A..43C. doi: 10.1051/0004-6361/200913322 . Retrieved 20 February 2020. (PDS data set)
    10. 1 2 Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). "Identification and Dynamical Properties of Asteroid Families". Asteroids IV: 297–321. arXiv: 1502.01628 . Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016.
    11. ↑ "Asteroid 926 Imhilde – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 20 February 2020.
    12. ↑ "Lahrer hinkender Bote – Kalender 1925". Badischen Landesbibliothek. 1925. p. 1. Retrieved 20 February 2020. Lahrer Bote archive
    13. ↑ "Lahrer hinkender Bote – Kalender 1925". Badischen Landesbibliothek. 1925. p. 10. Retrieved 20 February 2020.
    14. 1 2 3 4 "Asteroid 926 Imhilde". Small Bodies Data Ferret. Retrieved 20 February 2020.
    15. ↑ Warner, Brian D. (March 2004). "Rotation rates for asteroids 875, 926, 1679, 1796, 3915, 4209, and 34817" (PDF). Minor Planet Bulletin. 31 (1): 19–22. Bibcode:2004MPBu...31...19W. ISSN   1052-8091. Archived from the original (PDF) on 20 February 2020. Retrieved 20 February 2020.
    16. 1 2 "LCDB Data for (926) Imhilde". Asteroid Lightcurve Database (LCDB). Retrieved 20 February 2020.
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