1573 Väisälä, provisional designation 1949 UA, is a stony Phocaea asteroid, slow rotator and suspected tumbler from the inner regions of the asteroid belt, approximately 9 kilometers in diameter. It was discovered on 27 October 1949, by Belgian astronomer Sylvain Arend at the Royal Observatory of Belgium in Uccle, Belgium.[11] It was named for Finnish astronomer Yrjö Väisälä.[2]

1573 Väisälä
Discovery [1]
Discovered byS. Arend
Discovery siteUccle Obs.
Discovery date27 October 1949
MPC designation(1573) Väisälä
Named after
Yrjö Väisälä (astronomer)[2]
1949 UA
main-belt · Phocaea[3][4]
Orbital characteristics[1]
Epoch 4 September 2017 (JD 2458000.5)
Uncertainty parameter 0
Observation arc67.51 yr (24,659 days)
Aphelion2.9192 AU
Perihelion1.8243 AU
2.3717 AU
3.65 yr (1,334 days)
0° 16m 11.28s / day
Physical characteristics
Dimensions8.43±1.90 km[5]
9.083±0.055 km[6]
9.146±0.066 km[7]
9.77 km (IRAS:2)[8]
252 h[a]
0.2226 (IRAS:2)[8]
12.2[6] · 12.30[1][3] · 12.47[5] · 12.84±0.50[10]

Orbit and classificationEdit

The stony S-type asteroid is a member of the Phocaea family (701), a group of asteroids with similar orbital characteristics.[4] It orbits the Sun at a distance of 1.8–2.9 AU once every 3 years and 8 months (1,334 days). Its orbit has an eccentricity of 0.23 and an inclination of 25° with respect to the ecliptic.[1] Väisälä's observation arc begins on the night following its official discovery observation at Uccle, as no precoveries were taken and no prior identifications were made.[11]

Physical characteristicsEdit

Slow rotatorEdit

In September 2011, a rotational lightcurve of Väisälä was obtained from photometric observations made by Czech astronomer Petr Pravec at Ondřejov Observatory.[b] Its analysis gave a rotation period of 252 hours with a brightness variation of 0.76 magnitude (U=2).[a] This makes Väisälä one of the Top 200 slow rotators known to exist. The body is also suspected to be in a non-principal axis rotation (NPAR), colloquially called as "tumbling". As of 2017, no follow-up observations have been made of these provisional results.[3]

Diameter and albedoEdit

According to the space-based surveys carried out by the Infrared Astronomical Satellite IRAS, and NASA's Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Väisälä measures between 8.43 and 9.77 kilometers in diameter, and its surface has an albedo between 0.222 and 0.284.[5][6][7][8] The Collaborative Asteroid Lightcurve Link adopts the results obtained by IRAS, that is, an albedo of 0.2226 and a diameter of 9.77 kilometers using on an absolute magnitude of 12.30.[3]


This minor planet was named after Finnish astronomer, Yrjö Väisälä (1891–1971), a prolific discoverer of minor planets during the late 1930s and early 1940s.[2] In addition, a second minor planet, 2804 Yrjö, was named in his honor by pioneering Finnish female astronomer Liisi Oterma, and the lunar crater Väisälä also bears his name. The official naming citation was published by the Minor Planet Center on 31 January 1962 (M.P.C. 2116).[12]


  1. ^ a b Pravec (2012) web: rotation period 252 hours with a brightness amplitude of 0.76 mag. Pravec, P.; Wolf, M.; Sarounova, L. (2012) Summary figures at DEFPage_Local.php?AstInfo=1573%7CVaisala Collaborative Asteroid Lightcurve Link (CALL) for (1573) Vaisala
  2. ^ Light-Curve-Analysis of (1573) Väisälä Screenshot from data


  1. ^ a b c d "JPL Small-Body Database Browser: 1573 Vaisala (1949 UA)" (2017-05-02 last obs.). Jet Propulsion Laboratory. Retrieved 5 June 2017.
  2. ^ a b c Schmadel, Lutz D. (2007). "(1573) Väisälä". Dictionary of Minor Planet Names – (1573) Väisälä. Springer Berlin Heidelberg. p. 125. doi:10.1007/978-3-540-29925-7_1574. ISBN 978-3-540-00238-3.
  3. ^ a b c d e "LCDB Data for (1573) Väisälä". Asteroid Lightcurve Database (LCDB). Retrieved 29 December 2016.
  4. ^ a b "Asteroid 1573 Vaisala – Nesvorny HCM Asteroid Families V3.0". Small Bodies Data Ferret. Retrieved 26 October 2019.
  5. ^ a b c d 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 December 2016.
  6. ^ a b c d 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.
  7. ^ a b 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 December 2016.
  8. ^ a b c Tedesco, E. F.; Noah, P. V.; Noah, M.; Price, S. D. (October 2004). "IRAS Minor Planet Survey V6.0". NASA Planetary Data System – IRAS-A-FPA-3-RDR-IMPS-V6.0. Bibcode:2004PDSS...12.....T. Retrieved 17 October 2019.
  9. ^ 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. Retrieved 29 December 2016.
  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 December 2016.
  11. ^ a b "1573 Vaisala (1949 UA)". Minor Planet Center. Retrieved 29 December 2016.
  12. ^ 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.

External linksEdit