1534 Näsi

1534 Näsi, provisional designation 1939 BK, is a carbonaceous asteroid from the middle region of the asteroid belt, approximately 20 kilometers in diameter.

1534 Näsi
Shape model of Näsi from its lightcurve
Discovery [1]
Discovered byY. Väisälä
Discovery siteTurku Obs.
Discovery date20 January 1939
Designations
(1534) Näsi
Named after
Näsijärvi (Finnish lake)[2]
1939 BK · 1933 UQ
1957 EA · 1960 UB
1962 JA · A915 VB
A924 WE · A924 YE
main-belt · (middle)
Chloris
Orbital characteristics [1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc91.56 yr (33,443 days)
Aphelion3.4155 AU
Perihelion2.0404 AU
2.7279 AU
Eccentricity0.2520
4.51 yr (1,646 days)
174.04°
0° 13m 7.68s / day
Inclination9.7942°
62.135°
42.826°
Physical characteristics
Dimensions18.32±5.21 km[3]
19.51±0.36 km[4]
19.92±0.65 km[5]
22.11 km (derived)[6]
22.12±0.9 km (IRAS:6)[7]
27.52±6.50 km[8]
5.98±0.02 h[9]
7.93161±0.00005 h[10]
7.9338±0.0003 h[11]
7.94±0.02 h[12]
9.75 h[13]
0.035±0.015[8]
0.07±0.01[5]
0.0721 (derived)[6]
0.0754±0.006 (IRAS:6)[7]
0.08±0.04[3]
0.100±0.004[4]
SMASS = Cgh [1] · C [6][14]
11.7[7][4] · 11.75[6][13] · 11.80[3] · 11.88±0.24[14] · 11.9[1] · 11.93[5] · 11.96[11] · 12.05[8]

    It was discovered on 20 January 1939, by Finnish astronomer Yrjö Väisälä at Turku Observatory in Southwest Finland, and later named for the Finnish lake Näsijärvi.[2][15]

    Orbit and classification

    Näsi orbits the Sun in the central main-belt at a distance of 2.0–3.4 AU once every 4 years and 6 months (1,646 days). Its orbit has an eccentricity of 0.25 and an inclination of 10° with respect to the ecliptic.[1] It was first identified as A915 VB at Simeiz Observatory in 1915. The body's observation arc begins 15 years prior to its official discovery with its identification as 1924 YE at Heidelberg Observatory.[15]

    Physical characteristics

    Lightcurve observations

    In April 2007, the so-far best rated rotational lightcurve of Näsi was obtained by Jason Sauppe at Oakley Observatory in the United States. The lightcurve analysis gave a rotation period of 7.94 hours with a brightness variation of 0.35 magnitude (U=3-).[12]

    Periods from other photometric observations were obtained by astronomers René Roy in May 2016 (5.98 hours, Δ0.47 mag, U=2+),[9] Giovanni de Sanctis in the 1990s (9.75 hours, Δ0.22 mag, U=2),[13] Adrián Galád in October 2005 (7.9338 hours, Δ0.51 mag, U=2-),[11] and a period of 7.93161 hours modeled from various data sources and published in 2016 (U=n.a.).[10]

    Spectral type, diameter and albedo

    In the SMASS taxonomy, the carbonaceous C-type asteroid is also classified as a Cgh-subtype. According to the surveys carried out by the Infrared Astronomical Satellite IRAS, the Japanese Akari satellite, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Näsi measures between 18.32 and 27.52 kilometers in diameter and its surface has an albedo between 0.035 and 0.100.[3][4][5][7][8] The Collaborative Asteroid Lightcurve Link derives an albedo of 0.0721 and a diameter of 22.11 kilometers based on an absolute magnitude of 11.75.[6]

    Naming

    This minor planet is named for the large Finnish lake Näsijärvi, sometimes called "Näsi". It measures 256 square kilometers (99 sq mi) in size and is located only 95 metres above sea level.[2] The official naming citation was published by the Minor Planet Center on 20 February 1976 (M.P.C. 3929).[16]

    References
    1. "JPL Small-Body Database Browser: 1534 Nasi (1939 BK)" (2016-07-15 last obs.). Jet Propulsion Laboratory. Retrieved 30 June 2017.
    2. Schmadel, Lutz D. (2007). "(1534) Näsi". Dictionary of Minor Planet Names – (1534) Näsi. Springer Berlin Heidelberg. p. 122. doi:10.1007/978-3-540-29925-7_1535. ISBN 978-3-540-00238-3.
    3. 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. Retrieved 31 December 2016.
    4. 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. Retrieved 17 October 2019. (online, AcuA catalog p. 153)
    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 31 December 2016.
    6. "LCDB Data for (1534) Näsi". Asteroid Lightcurve Database (LCDB). Retrieved 31 December 2016.
    7. 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 22 October 2019.
    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. Retrieved 31 December 2016.
    9. Behrend, Raoul. "Asteroids and comets rotation curves – (1534) Näsi". Geneva Observatory. Retrieved 31 December 2016.
    10. Hanus, J.; Durech, J.; Oszkiewicz, D. A.; Behrend, R.; Carry, B.; Delbo, M.; et al. (February 2016). "New and updated convex shape models of asteroids based on optical data from a large collaboration network". Astronomy and Astrophysics. 586: 24. arXiv:1510.07422. Bibcode:2016A&A...586A.108H. doi:10.1051/0004-6361/201527441.
    11. Galád, A. (May 2010). "Accuracy of calibrated data from the SDSS moving object catalog, absolute magnitudes, and probable lightcurves for several asteroids". Astronomy and Astrophysics. 514: 10. Bibcode:2010A&A...514A..55G. doi:10.1051/0004-6361/201014029. Retrieved 31 December 2016.
    12. Sauppe, Jason; Torno, Steven; Lemke-Oliver, Robert; Ditteon, Richard (December 2007). "Asteroid Lightcurve Analysis at the Oakley Observatory - March/April 2007". The Minor Planet Bulletin. 34 (4): 119–122. Bibcode:2007MPBu...34..119S. ISSN 1052-8091. Retrieved 31 December 2016.
    13. de Sanctis, M. C.; Barucci, M. A.; Angeli, C. A.; Fulchignoni, M.; Burchi, R.; Angelini, P. (October 1994). "Photoelectric and CCD observations of 10 asteroids". Planetary and Space Science. 42 (10): 859–864. Bibcode:1994P&SS...42..859D. doi:10.1016/0032-0633(94)90066-3. ISSN 0032-0633. Retrieved 31 December 2016.
    14. 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 31 December 2016.
    15. "1534 Nasi (1939 BK)". Minor Planet Center. Retrieved 31 December 2016.
    16. Schmadel, Lutz D. "Appendix – Publication Dates of the MPCs". Dictionary of Minor Planet Names – Addendum to Fifth Edition (2006–2008). Springer Berlin Heidelberg. p. 221. doi:10.1007/978-3-642-01965-4. ISBN 978-3-642-01964-7.

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