2195 Tengström, provisional designation 1941 SP, is a stony Florian 1 asteroid from the inner regions of the asteroid belt, approximately 8 kilometers in diameter. It was discovered on 27 September 1941, by Finnish astronomer Liisi Oterma at Turku Observatory in Southwest Finland, and named for Swedish geodesist  Erik Tengström.
Orbit and classification
Tengström is a member of the Flora family of stony asteroids, one of the largest families of the main belt. It orbits the Sun in the inner main-belt at a distance of 2.0–2.5 AU once every 3 years and 4 months (1,210 days). Its orbit has an eccentricity of 0.11 and an inclination of 5 ° with respect to the ecliptic. It was first identified as  1931 TC at 3 Lowell Observatory in 1931, extending the asteroid's observation arc by 10 years prior to its official discovery observation at Turku.
Tengström has been characterized as a metallic M-type and stony S-type asteroid. 
Between 2006 and 2016, several well defined rotational
lightcurves of Tengström were obtained by astronomers David Higgins, Petr Pravec, Pierre Antonini and René Roy ( ). U=3/3/3/3/3  [a] [b] Lightcurve analysis gave a [c] rotation period of 2.821 hours with a brightness variation between 0.17 and 0.45 magnitude. For an asteroid of its size, [d] Tengström has a relatively fast spin rate, not far from the 2.2-hour threshold for fast rotators.
Diameter and albedo
According to the survey carried out by NASA's
Wide-field Infrared Survey Explorer with its subsequent NEOWISE mission, Tengström measures between 7.14 and 8.73 kilometers in diameter and its surface has a high albedo of 0.34 to 0.45. NEOWISE also classifies it as a metallic asteroid, despite its much higher albedo.    The  Collaborative Asteroid Lightcurve Link assumes an albedo of 0.24 – derived from 8 Flora, the family's largest member and namesake – and calculates a diameter of 8.98 kilometers using an absolute magnitude of 12.4.
minor planet was named after Swedish geodesist and astronomer Erik Tengström (1913–1996), emeritus professor at Uppsala University on the celebration of his 70th anniversary. The official naming citation was published by the  Minor Planet Center on 28 March 1983 ( ). M.P.C. 7782
^ a b Pravec (2011) web: rotation period
hours; amplitude of 2.820 92 ±0.000 04 mag.; quality code of 3. Summary figures for (2195) Tengström at 0.31 Collaborative Asteroid Lightcurve Link (CALL) and Pravec, P.; Wolf, M.; Sarounova, L. (2011)
^ a b Pravec (2016) web: rotation period
hours; amplitude of 2.8210 ±0.0001 mag.; quality code of 3. Summary figures for (2195) Tengström at 0.21 Collaborative Asteroid Lightcurve Link (CALL) and Pravec, P.; Wolf, M.; Sarounova, L. (2016)
^ a b Higgins (2011) web: rotation period
hours; amplitude of 2.821 12 ±0.000 07 mag.; quality code of 3. Summary figures for (2195) Tengström at 0.17 Collaborative Asteroid Lightcurve Link (CALL)
^ Lightcurve plot from
December 2011, 2.82092 hours and April 2016, 2.8210 hours by Pray, Kusnirak, Pravec Ondřejov Observatory – unpublished data
^ a b c d
"JPL Small-Body Database Browser: 2195 Tengstrom (1941 SP1)" (2017-05-04 last obs.). Jet Propulsion Laboratory . Retrieved . 11 June 2017
^ a b c
Schmadel, Lutz D. (2007). "(2195) Tengström". Dictionary of Minor Planet Names – (2195) Tengström. Springer Berlin Heidelberg. p. 178. doi: 10.1007/978-3-540-29925-7_2196. ISBN . 978-3-540-00238-3
^ a b c d e f g
"LCDB Data for (2195) Tengström". Asteroid Lightcurve Database (LCDB) . Retrieved . 17 February 2017
^ a b c d
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 . 17 February 2017
^ a b c d
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 . 17 February 2017
^ a b c
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 . 17 February 2017
^ a b c d e f
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.
Higgins, David; Pravec, Petr; Kusnirak, Peter; Galad, Adrian; Kornos, Leos; Pray, Donald; et al. (December 2006). "Asteriod lightcurve analysis at Hunters Hill Observatory and collaborating stations - autumn 2006". The Minor Planet Bulletin. 33 (4): 89–91. Bibcode: 2006MPBu...33...89H. ISSN 1052-8091 . Retrieved . 17 February 2017
^ a b c d
Behrend, Raoul. "Asteroids and comets rotation curves – (2195) Tengström". Geneva Observatory . Retrieved . 17 February 2017
^ a b
Waszczak, Adam; Chang, Chan-Kao; Ofek, Eran O.; Laher, Russ; Masci, Frank; Levitan, David; et al. (September 2015). "Asteroid Light Curves from the Palomar Transient Factory Survey: Rotation Periods and Phase Functions from Sparse Photometry". The Astronomical Journal. 150 (3): 35. arXiv: . 1504.04041 Bibcode: 2015AJ....150...75W. doi: 10.1088/0004-6256/150/3/75 . Retrieved . 17 February 2017
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 . 17 February 2017
^ a b
"2195 Tengstrom (1941 SP1)". Minor Planet Center . Retrieved . 17 February 2017
"MPC/MPO/MPS Archive". Minor Planet Center . Retrieved . 17 February 2017