1335 Demoulina

1335 Demoulina, provisional designation 1934 RE, is a stony Florian asteroid from the inner regions of the asteroid belt, approximately 7 kilometers in diameter. Discovered by Karl Reinmuth at Heidelberg Observatory in 1934, the asteroid was named after Prof. Demoulin, a Belgian astronomer at Ghent University. It has a slower-than average spin rate of nearly 75 hours.

1335 Demoulina
Shape model of Demoulina from its lightcurve
Discovery [1]
Discovered byK. Reinmuth
Discovery siteHeidelberg Obs.
Discovery date7 September 1934
Designations
(1335) Demoulina
Named after
Prof. Demoulin [2]
(Belgian astronomer)
1934 RE · 1954 RA
main-belt · (inner)
Flora [3] · background [4]
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc82.66 yr (30,191 days)
Aphelion2.5854 AU
Perihelion1.8955 AU
2.2404 AU
Eccentricity0.1540
3.35 yr (1,225 days)
255.64°
0° 17m 38.04s / day
Inclination2.5472°
172.62°
198.89°
Physical characteristics
Dimensions6.35±1.43 km[5]
7.47 km (calculated)[3]
7.484±0.130 km[6]
7.684±0.133 km[7]
2.59±0.05 h (poor)[8]
74.86±0.10 h[9]
0.2073±0.0275[7]
0.218±0.043[6]
0.24 (assumed)[3]
0.26±0.14[5]
S (assumed)[3]
12.8[3] · 12.9[1][7] · 13.06[5] · 13.89±0.74[10]

    Discovery

    Demoulina was discovered on 7 September 1934, by German astronomer Karl Reinmuth at the Heidelberg-Königstuhl State Observatory in southwest Germany.[11] Six nights later, it was independently discovered by Belgian astronomer Eugène Delporte at Uccle Observatory on 13 September 1934.[2] The Minor Planet Center only recognizes the first discoverer.[11]

    Orbit and classification

    Demoulina is a member of the Flora family (402), a giant asteroid family and the largest family of stony asteroids in the asteroid belt.[3] However, it is a non-family asteroid of the main belt's background population when applying the Hierarchical Clustering Method to its proper orbital elements.[4]

    It orbits the Sun in the inner asteroid belt at a distance of 1.9–2.6 AU once every 3 years and 4 months (1,225 days; semi-major axis of 2.24 AU). Its orbit has an eccentricity of 0.15 and an inclination of 3° with respect to the ecliptic.[1] The body's observation arc begins with its official discovery observation at Heidelberg in 1934.[11]

    Physical characteristics

    Demoulina is an assumed S-type asteroid.[3]

    Rotation period

    In February 2006, a rotational lightcurve of Demoulina was obtained from photometric observations by American astronomers Lawrence Molnar and Melissa Haegert at the Calvin–Rehoboth Observatory in New Mexico. Lightcurve analysis gave a rotation period of 74.86 hours with a brightness amplitude of 0.78 magnitude (U=2+).[9] While not being a slow rotator, Demoulina's period is significantly longer than that for most asteroids. Its high brightness amplitude also indicates that it has an irregular or elongated shape.

    Other photometric lightcurves which are based on a single night of observation are rated poorly (U=1).[8]

    Diameter and albedo

    According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Demoulina measures between 6.35 and 7.684 kilometers in diameter and its surface has an albedo between 0.2073 and 0.26.[5][6][7]

    The Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, the parent body of the Flora family, and calculates a diameter of 7.47 kilometers based on an absolute magnitude of 12.8.[3]

    Naming

    This minor planet was named after Prof. Demoulin, a Belgian astronomer at Ghent University. The official naming citation was mentioned in The Names of the Minor Planets by Paul Herget in 1955 (H 121).[2]

    gollark: Deploying countermatrices.
    gollark: Actually, our functions are shielded and merely reflect incoming lasers in the line y = 10 + |x|.
    gollark: If it worked, of course; the function is filled with embedded contraapioforms.
    gollark: That would just give you an apiaristic version of the original function.
    gollark: Too bad, my function is continuous but cannot be differentiated.

    References
    1. "JPL Small-Body Database Browser: 1335 Demoulina (1934 RE)" (2017-05-05 last obs.). Jet Propulsion Laboratory. Retrieved 29 November 2017.
    2. Schmadel, Lutz D. (2007). "(1335) Demoulina". Dictionary of Minor Planet Names – (1335) Demoulina. Springer Berlin Heidelberg. p. 109. doi:10.1007/978-3-540-29925-7_1336. ISBN 978-3-540-00238-3.
    3. "LCDB Data for (1335) Demoulina". Asteroid Lightcurve Database (LCDB). Retrieved 29 November 2017.
    4. "Asteroid 1335 Demoulina – Proper Elements". AstDyS-2, Asteroids – Dynamic Site. Retrieved 29 October 2019.
    5. 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. Retrieved 29 November 2017.
    6. Masiero, Joseph R.; Mainzer, A. K.; Grav, T.; Bauer, J. M.; Cutri, R. M.; Dailey, J.; et al. (November 2011). "Main Belt Asteroids with WISE/NEOWISE. I. Preliminary Albedos and Diameters". The Astrophysical Journal. 741 (2): 20. arXiv:1109.4096. Bibcode:2011ApJ...741...68M. doi:10.1088/0004-637X/741/2/68. Retrieved 29 November 2017.
    7. 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.
    8. Behrend, Raoul. "Asteroids and comets rotation curves – (1335) Demoulina". Geneva Observatory. Retrieved 29 November 2017.
    9. Molnar, Lawrence A.; Haegert, Melissa J. (December 2007). "Lightcurve Analysis of Five Main-belt Asteroids at the Calvin-Rehoboth Observatory". The Minor Planet Bulletin. 34 (4): 126–128. Bibcode:2007MPBu...34..126M. ISSN 1052-8091. Retrieved 29 November 2017.
    10. Veres, Peter; Jedicke, Robert; Fitzsimmons, Alan; Denneau, Larry; Granvik, Mikael; Bolin, Bryce; et al. (November 2015). "Absolute magnitudes and slope parameters for 250,000 asteroids observed by Pan-STARRS PS1 - Preliminary results". Icarus. 261: 34–47. arXiv:1506.00762. Bibcode:2015Icar..261...34V. doi:10.1016/j.icarus.2015.08.007. Retrieved 29 November 2017.
    11. "1335 Demoulina (1934 RE)". Minor Planet Center. Retrieved 29 November 2017.

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