Astronomy:21795 Masi
| Discovery [1] | |
|---|---|
| Discovered by | F. Mallia |
| Discovery site | Campo Catino Obs. |
| Discovery date | 29 September 1999 |
| Designations | |
| (21795) Masi | |
| Named after | Gianluca Masi [1] (Italian astronomer) |
| 1999 SN9 · 1988 UE 1993 BZ1 | |
| Minor planet category | main-belt [1][2] · (inner) Nysa [3] |
| Orbital characteristics [2] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 64.45 yr (23,541 d) |
| |{{{apsis}}}|helion}} | 2.8409 AU |
| |{{{apsis}}}|helion}} | 1.9222 AU |
| 2.3815 AU | |
| Eccentricity | 0.1929 |
| Orbital period | 3.68 yr (1,342 d) |
| Mean anomaly | 337.35° |
| Mean motion | 0° 16m 5.52s / day |
| Inclination | 1.8376° |
| Longitude of ascending node | 337.09° |
| 81.681° | |
| Physical characteristics | |
| Mean diameter | 2.45 km (calculated)[4] 3.150±0.164 km[5][6] |
| Rotation period | 13.862±0.0121 h[7] |
| Geometric albedo | 0.20 (assumed)[4] 0.235±0.037[5][6] |
| S (assumed)[4] | |
| Absolute magnitude (H) | 14.7[6] 14.9[2] 14.970±0.004 (R)[7] 15.41±0.14[8] 15.42[4] |
21795 Masi (provisional designation 1999 SN9) is a Nysian asteroid from the inner regions of the asteroid belt, approximately 3 kilometers (2 miles) in diameter. It was discovered on 29 September 1999, by Italian amateur astronomer Franco Mallia at the Campo Catino Astronomical Observatory in Lazio, Italy.[1] The likely S-type asteroid has a rotation period of 13.86 hours.[4] It was named for Italian astronomer Gianluca Masi.[1]
Orbit and classification
Masi is member of the Nysa family (405),[3] located in the Nysa–Polana complex and one of the largest asteroid families of the asteroid belt, named after 44 Nysa.[9] It orbits the Sun in the inner main-belt at a distance of 1.9–2.8 AU once every 3 years and 8 months (1,342 days; semi-major axis of 2.38 AU). Its orbit has an eccentricity of 0.19 and an inclination of 2° with respect to the ecliptic.[2] The body's observation arc begins with a precovery published by the Digitized Sky Survey and taken at the Palomar Observatory in April 1954, more than 45 years prior to its official discovery observation at Campo Catino.[1]
Physical characteristics
Masi is an assumed, stony S-type asteroid,[4] which is also the overall spectral type for members of the Nysa family of asteroids.[9]:23
Rotation period
In September 2010, a rotational lightcurve of Masi was obtained from photometric observations in the R-band by astronomers at the Palomar Transient Factory in California. Lightcurve analysis gave a rotation period of 13.862 hours with a relatively high brightness amplitude of 0.68 magnitude ({{{1}}}).[7]
Diameter and albedo
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, Masi measures 3.150 kilometers in diameter and its surface has an albedo of 0.235,[5][6] while the Collaborative Asteroid Lightcurve Link assumes a standard albedo for a stony asteroid of 0.20, and calculates a diameter of 2.45 kilometers based on an absolute magnitude of 15.42.[4]
Naming
This minor planet was named after Italian astrophysicist and astronomer, Gianluca Masi (born 1972), a researcher and discoverer of minor planets and variable stars, who became an avid amateur astronomer when he was 8 years old.[1] The official naming citation was published by the Minor Planet Center on 9 May 2001 (M.P.C. 42679).[10]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 "21795 Masi (1999 SN9)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=21795.
- ↑ 2.0 2.1 2.2 2.3 "JPL Small-Body Database Browser: 21795 Masi (1999 SN9)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2021795.
- ↑ 3.0 3.1 "Asteroid 21795 Masi". Small Bodies Data Ferret. https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=21795+Masi.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 4.6 "LCDB Data for (21795) Masi". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=21795%7CMasi.
- ↑ 5.0 5.1 5.2 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. doi:10.1088/0004-637X/741/2/68. Bibcode: 2011ApJ...741...68M.
- ↑ 6.0 6.1 6.2 6.3 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. doi:10.1088/0004-637X/741/2/90. Bibcode: 2011ApJ...741...90M. (catalog)
- ↑ 7.0 7.1 7.2 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. doi:10.1088/0004-6256/150/3/75. Bibcode: 2015AJ....150...75W.
- ↑ 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. doi:10.1016/j.icarus.2015.08.007. Bibcode: 2015Icar..261...34V.
- ↑ 9.0 9.1 Nesvorný, D.; Broz, M.; Carruba, V. (December 2014). "Identification and Dynamical Properties of Asteroid Families". Asteroids IV. pp. 297–321. doi:10.2458/azu_uapress_9780816532131-ch016. ISBN 9780816532131. Bibcode: 2015aste.book..297N.
- ↑ "MPC/MPO/MPS Archive". Minor Planet Center. https://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html.
External links
- Asteroid Lightcurve Database (LCDB), query form (info )
- Dictionary of Minor Planet Names, Google books
- Discovery Circumstances: Numbered Minor Planets (20001)-(25000) – Minor Planet Center
- 21795 Masi at AstDyS-2, Asteroids—Dynamic Site
- 21795 Masi at the JPL Small-Body Database
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