11277 Ballard

11277 Ballard, provisional designation 1988 TW2, is a Phocaea asteroid from the inner regions of the asteroid belt, approximately 6.3 kilometers (3.9 miles) in diameter. It was discovered on 8 October 1988, by American astronomer couple Carolyn and Eugene Shoemaker at the Palomar Observatory in California.[1] The assumed S-type asteroid has a rotation period of at least 10 hours.[4] It was named for American marine scientist Robert Ballard.[1]

11277 Ballard
Discovered byC. Shoemaker
E. Shoemaker
Discovery sitePalomar Obs.
Discovery date8 October 1988
MPC designation(11277) Ballard
Named after
Robert Ballard[1]
(American oceanographer)
1988 TW2 · 1995 MG
main-belt[1][2] · (inner)
Orbital characteristics[2]
Epoch 23 March 2018 (JD 2458200.5)
Uncertainty parameter 0
Observation arc28.73 yr (10,493 d)
Aphelion2.9757 AU
Perihelion1.8295 AU
2.4026 AU
3.72 yr (1,360 d)
 15m 52.92s / day
Physical characteristics
Mean diameter
6.298±0.075 km[3][5][6]
>10 h[7]
S (assumed)[4]

    Orbit and classification

    Ballard is a member of the Phocaea family (701).[3] It orbits the Sun in the inner asteroid belt at a distance of 1.83–2.98 AU once every 3 years and 9 months (1,360 days; semi-major axis of 2.4 AU). Its orbit has an eccentricity of 0.24 and an inclination of 23° with respect to the ecliptic.[2] The body's observation arc begins with a precovery taken at Palomar in September 1988, just four weeks prior to its official discovery observation.[1] Ballard is not a Mars-crosser, since its aphelion is larger than 1.67 AU.[2]


    This minor planet was named after American marine scientist Robert Ballard (born 1942), a professor of oceanography and director of the Deep Submergence Laboratory, who is known for the discovery of the RMS Titanic and the German battleship Bismarck. The official naming citation was published by the Minor Planet Center on 26 May 2002 (M.P.C. 45748).[12]

    Physical characteristics

    Ballard is an assumed, stony S-type asteroid,[4] in line with the Phocaea family's overall spectral type.[13]:23

    Rotation period

    In July 2010, a rotational lightcurve of Ballard was obtained from two nights of photometric observations in the R-band by Italian astronomer Albino Carbognani at the OAVdA Observatory (B04) in Italy. Lightcurve analysis gave a tentative rotation period of at least 10 hours with a brightness amplitude of more than 0.25 magnitude (U=2-).[7]

    Diameter and albedo

    According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Ballard measures between 5.65 and 6.445 kilometers in diameter and its surface has an albedo between 0.19 and 0.289.[3][4][5][6][8][9][10][11]

    The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.23 – derived from the family's largest member, 25 Phocaea – and calculates a diameter of 6.65 kilometers based on an absolute magnitude of 13.1.[4]


    1. "11277 Ballard (1988 TW2)". Minor Planet Center. Retrieved 25 September 2018.
    2. "JPL Small-Body Database Browser: 11277 Ballard (1988 TW2)" (2017-06-05 last obs.). Jet Propulsion Laboratory. Retrieved 25 September 2018.
    3. "Asteroid 11277 Ballard". Small Bodies Data Ferret. Retrieved 25 September 2018.
    4. "LCDB Data for (11277) Ballard". Asteroid Lightcurve Database (LCDB). Retrieved 25 September 2018.
    5. 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. Retrieved 25 September 2018.
    6. 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.
    7. Carbognani, Albino (January 2011). "Lightcurves and Periods of Eighteen NEAs and MBAs". The Minor Planet Bulletin. 38 (1): 57–63. Bibcode:2011MPBu...38...57C. ISSN 1052-8091.
    8. Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Nugent, C.; et al. (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.
    9. 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. (catalog)
    10. Nugent, C. R.; Mainzer, A.; Masiero, J.; Bauer, J.; Cutri, R. M.; Grav, T.; et al. (December 2015). "NEOWISE Reactivation Mission Year One: Preliminary Asteroid Diameters and Albedos". The Astrophysical Journal. 814 (2): 13. arXiv:1509.02522. Bibcode:2015ApJ...814..117N. doi:10.1088/0004-637X/814/2/117.
    11. Nugent, C. R.; Mainzer, A.; Bauer, J.; Cutri, R. M.; Kramer, E. A.; Grav, T.; et al. (September 2016). "NEOWISE Reactivation Mission Year Two: Asteroid Diameters and Albedos". The Astronomical Journal. 152 (3): 12. arXiv:1606.08923. Bibcode:2016AJ....152...63N. doi:10.3847/0004-6256/152/3/63.
    12. "MPC/MPO/MPS Archive". Minor Planet Center. Retrieved 25 September 2018.
    13. Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). Identification and Dynamical Properties of Asteroid Families. Asteroids IV. pp. 297–321. arXiv:1502.01628. Bibcode:2015aste.book..297N. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN 9780816532131.

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