Astronomy:9965 GNU
 Orbits of GNU (blue), the inner planets and Jupiter (outermost) | |
| Discovery [1] | |
|---|---|
| Discovered by | Spacewatch |
| Discovery site | Kitt Peak National Obs. |
| Discovery date | 5 March 1992 |
| Designations | |
| (9965) GNU | |
| Named after | GNU Project [1] (free software project) |
| 1992 EF2 · 1988 BD4 1993 QR3 | |
| Minor planet category | main-belt [1][2] · (inner) background [3] |
| Orbital characteristics [2] | |
| Epoch 23 March 2018 (JD 2458200.5) | |
| Uncertainty parameter 0 | |
| Observation arc | 30.17 yr (11,019 d) |
| |{{{apsis}}}|helion}} | 2.8283 AU |
| |{{{apsis}}}|helion}} | 2.0080 AU |
| 2.4181 AU | |
| Eccentricity | 0.1696 |
| Orbital period | 3.76 yr (1,373 d) |
| Mean anomaly | 276.39° |
| Mean motion | 0° 15m 43.56s / day |
| Inclination | 12.206° |
| Longitude of ascending node | 156.48° |
| 82.938° | |
| Physical characteristics | |
| Mean diameter | 2.07±0.53 km[4] 4.10 km (calculated)[5] 6.22±2.14 km[6] 6.293±0.159 km[7][8] |
| Rotation period | 39.720±0.1589 h (R)[9] 39.745±0.1589 h (S)[9] |
| Geometric albedo | 0.102±0.014[7] 0.1022±0.0145[8] 0.105±0.125[6] 0.20 (assumed)[5] 0.53±0.12[4] |
| D (Pan-STARRS)[10] S (SDSS-MOC)[11] S (assumed)[5] | |
| Absolute magnitude (H) | 14.10[6][8] 14.3[2][5] 14.31±0.14[10] 14.398±0.005 (R)[9] 14.72[4] 14.966±0.011 (S)[9] |
9965 GNU, provisional designation 1992 EF2, is a background asteroid from the inner regions of the asteroid belt, approximately 4 kilometers (2 miles) in diameter. It was discovered on 5 March 1992, by astronomer of the Spacewatch program at the Kitt Peak National Observatory in Arizona, United States.[1] The uncertain D-type asteroid has a long rotation period of 39.7 hours.[5] It was named for the free-software GNU Project.[1]
Orbit and classification
GNU is a non-family asteroid from the main belt's background population.[3]
It orbits the Sun in the inner asteroid belt at a distance of 2.0–2.8 AU once every 3 years and 9 months (1,373 days; semi-major axis of 2.42 AU). Its orbit has an eccentricity of 0.17 and an inclination of 12° with respect to the ecliptic.[2] The body's observation arc begins with its first observation as 1988 BD4 at La Silla Observatory in January 1988, or 4 years prior to its official discovery observation at Kitt Peak.[1]
Physical characteristics
GNU has been characterized as a dark D-type asteroid by Pan-STARRS' survey and in the SDSS-based taxonomy.[10][11] It is also an assumed S-type asteroid, the most common type in the inner asteroid belt.[5]
Rotation period
In September and October 2012, two rotational lightcurves of GNU were obtained from photometric observations by astronomers at the Palomar Transient Factory in California. Lightcurve analysis gave a rotation period of 39.720 and 39.745 hours, with a brightness amplitude of 0.36 and 0.42 magnitude in the R- and S-band, respectively ({{{1}}}).[9] While not being a slow rotator, GNU' period is significantly longer than the average spin rate of 2 to 20 hours, seen among the majority of asteroids.
Diameter and albedo
According to the survey carried out by the NEOWISE mission of NASA's Wide-field Infrared Survey Explorer, GNU measures between 2.07 and 6.293 kilometers in diameter and its surface has an albedo between 0.102 and 0.53.[4][6][7][8] The Collaborative Asteroid Lightcurve Link assumes a standard albedo for a stony asteroid of 0.20 and calculates a diameter of 4.10 kilometers based on an absolute magnitude of 14.3.[5]
Naming
This minor planet was named for the free-software GNU Project, created by Richard Stallman 1984. GNU is the recursive acronym for "GNU is not Unix". The collaborative projects enables programmers to trade and improve upon free software.[1] The official naming citation was published by the Minor Planet Center on 11 November 2000 (M.P.C. 41571).[12]
References
- ↑ 1.0 1.1 1.2 1.3 1.4 1.5 1.6 "9965 GNU (1992 EF2)". Minor Planet Center. https://www.minorplanetcenter.net/db_search/show_object?object_id=9965.
- ↑ 2.0 2.1 2.2 2.3 "JPL Small-Body Database Browser: 9965 GNU (1992 EF2)". Jet Propulsion Laboratory. https://ssd.jpl.nasa.gov/sbdb.cgi?sstr=2009965.
- ↑ 3.0 3.1 "Asteroid 9965 GNU". Small Bodies Data Ferret. https://sbntools.psi.edu/ferret/SimpleSearch/results.action?targetName=9965+GNU.
- ↑ 4.0 4.1 4.2 4.3 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. doi:10.3847/0004-6256/152/3/63. Bibcode: 2016AJ....152...63N.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 "LCDB Data for (9965) GNU". Asteroid Lightcurve Database (LCDB). http://www.minorplanet.info/PHP/generateOneAsteroidInfo.php?AstInfo=9965%7CGNU.
- ↑ 6.0 6.1 6.2 6.3 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. doi:10.1088/2041-8205/759/1/L8. Bibcode: 2012ApJ...759L...8M.
- ↑ 7.0 7.1 7.2 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.
- ↑ 8.0 8.1 8.2 8.3 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)
- ↑ 9.0 9.1 9.2 9.3 9.4 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.
- ↑ 10.0 10.1 10.2 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.
- ↑ 11.0 11.1 Carvano, J. M.; Hasselmann, P. H.; Lazzaro, D.; Mothé-Diniz, T. (February 2010). "SDSS-based taxonomic classification and orbital distribution of main belt asteroids". Astronomy and Astrophysics 510: 12. doi:10.1051/0004-6361/200913322. Bibcode: 2010A&A...510A..43C. https://sbnarchive.psi.edu/pds3/non_mission/EAR_A_I0035_5_SDSSTAX_V1_1/data/sdsstax_ast_table.tab. Retrieved 30 October 2019. (PDS data set)
- ↑ "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 (5001)-(10000) – Minor Planet Center
- 9965 GNU at AstDyS-2, Asteroids—Dynamic Site
- 9965 GNU at the JPL Small-Body Database
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