1777 Gehrels

1777 Gehrels
Discovery [1]
Discovered by Palomar–Leiden survey
C. J. van Houten, I. van Houten-Groeneveld and Tom Gehrels
Discovery site Palomar Obs.
Discovery date 24 September 1960
Designations
MPC designation 1777 Gehrels
Named after
 Tom Gehrels
(astronomer)[2]
4007 P–L · 1937 GN
1941 BU · 1951 QB
1958 DA · A905 UE
A923 AA
main-belt · (middle) [3]
Orbital characteristics [1]
Epoch 27 June 2015 (JD 2457200.5)
Uncertainty parameter 0
Observation arc 109.91 yr (40,145 days)
Aphelion 2.6723 AU
Perihelion 2.5810 AU
2.6266 AU
Eccentricity 0.0173
4.26 yr (1,555 days)
213.44°
Inclination 3.1478°
334.69°
129.99°
Physical characteristics
Dimensions 12.486±0.228 km[4]
12.667 km[5]
13.14±1.25 km[6]
12.67 km (taken)[3]
2.83552 h[7]
2.840±0.004 h[8]
2.8358±0.0001 h[9]
2.837±0.002 h[7]
2.83±0.05 h[7]
2.8356±0.0002 h[lower-alpha 1]
2.8356±0.0001 h[lower-alpha 1]
0.2212±0.0170[4]
0.2151[5]
0.277±0.274[6]
SMASS = Sq
S [3]
11.6

    1777 Gehrels, also designated 4007 P–L, is an asteroid from the middle region of the asteroid belt, about 13 kilometers in diameter. It was discovered during the Palomar–Leiden survey by the Dutch astronomer couple Ingrid and Cornelis van Houten, in collaboration with Dutch–American astronomer Tom Gehrels at Palomar Observatory, California, on 24 September 1960.[10]

    The stony asteroid is classified as a transitional Sq-type in the SMASS classification taxonomy. It orbits the Sun at a distance of 2.6–2.7 AU once every 4 years and 3 months (1,555 days). Its orbit shows an eccentricity of 0.02 and is tilted by 3 degrees to the plane of the ecliptic. It has an albedo of around 0.22 to 0.28.[5][6] and rotates every 2.8 hours around its axis.[7][8][9][lower-alpha 1]

    The designation P–L stands for Palomar–Leiden, named after Palomar Observatory and Leiden Observatory, which collaborated on the fruitful Palomar–Leiden survey in the 1960s. Gehrels used Palomar's Samuel Oschin telescope (also known as the 48-inch Schmidt Telescope), and shipped the photographic plates to Ingrid and Cornelis van Houten at Leiden Observatory. The trio are credited with several thousand asteroid discoveries.

    The minor planet was named in honor of Dutch-born American astronomer Tom Gehrels (1925–2011), professor at the University of Arizona, staff member of the LPL research center at Tucson, a principal investigator in the Pioneer program, receiver of the Masursky Award, initiator of the Spacewatch project, and co-discoverer of thousands of minor planets in the Palomar–Leiden survey (see above). He was a pioneer in the field of photometric and polarimetric observations of Solar System bodies in the 1950s.[2][11]

    References

    1. 1 2 3 Pravec (2005) web: rotation period 2.8356±0.0002 hours with a brightness amplitude of 0.23 mag. Pravec (1990) web:rotation period 2.8356±0.0001 hours with a brightness amplitude of 0.21 mag. Summary figures at Collaborative Asteroid Lightcurve Link (CALL) for (1777) Gehrels
    1. 1 2 "JPL Small-Body Database Browser: 1777 Gehrels (4007 P-L)" (2015-10-02 last obs.). Jet Propulsion Laboratory. Retrieved November 2015.
    2. 1 2 Schmadel, Lutz D. (2003). Dictionary of Minor Planet Names – (1777) Gehrels. Springer Berlin Heidelberg. p. 142. ISBN 978-3-540-29925-7. Retrieved November 2015.
    3. 1 2 3 "LCDB Data for (1777) Gehrels". Asteroid Lightcurve Database (LCDB). Retrieved November 2015.
    4. 1 2 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. Retrieved November 2015.
    5. 1 2 3 Pravec, Petr; Harris, Alan W.; Kusnirák, Peter; Galád, Adrián; Hornoch, Kamil (September 2012). "Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations". Icarus 221 (1): 365–387. Bibcode:2012Icar..221..365P. doi:10.1016/j.icarus.2012.07.026. Retrieved November 2015.
    6. 1 2 3 Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; Cabrera, M. S. (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. Retrieved November 2015.
    7. 1 2 3 4 Behrend, Raoul. "Asteroids and comets rotation curves – (1777) Gehrels". Geneva Observatory. Retrieved November 2015.
    8. 1 2 Wisniewski, W. Z.; Michalowski, T. M.; Harris, A. W.; McMillan, R. S. (March 1995). "Photoelectric Observations of 125 Asteroids". Abstracts of the Lunar and Planetary Science Conference. Bibcode:1995LPI....26.1511W. Retrieved November 2015.
    9. 1 2 Stephens, Robert D. (September 2005). "Asteroid lightcurve photometry from Santana Observatory - winter 2005". Bulletin of the Minor Planets (Section of the Association of Lunar and Planetary Observers) 32 (3): 66–68. Bibcode:2005MPBu...32...66S. ISSN 1052-8091. Retrieved November 2015.
    10. ↑ "1777 Gehrels (4007 P-L)". Minor Planet Center. Retrieved November 2015.
    11. ↑ Jeff Harrison (12 July 2011). "Astronomer Tom Gehrels, 1925–2011". University of Arizona. Retrieved November 2015.

    External links


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