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词条 (31345) 1998 PG
释义

  1. Orbit

      Close approaches  

  2. Physical characteristics

      Spectral type    Diameter and albedo    Rotation  

  3. Moon

  4. Numbering and naming

  5. Gallery

  6. Notes

  7. References

  8. External links

{{Infobox planet
| minorplanet = yes
| name = (31345) 1998 PG
| background = #FFC2E0
| image =
| image_size =
| caption =
| discovery_ref =  
| discovered = 3 August 1998
| discoverer = LONEOS
| discovery_site = Anderson Mesa Stn.
| mpc_name = (31345) 1998 PG
| alt_names = 1998 PG
| pronounced =
| named_after =
| mp_category = NEO{{·}}Amor [3]
| orbit_ref =  
| epoch = 4 September 2017 (JD 2458000.5)
| uncertainty = 0
| observation_arc = 38.54 yr (14,075 days)
| aphelion = 2.8048 AU
| perihelion = 1.2277 AU
| semimajor = 2.0162 AU
| eccentricity = 0.3911
| period = 2.86 yr (1,046 days)
| mean_anomaly = 215.36°
| mean_motion = {{Deg2DMS|0.3443|sup=ms}} / day
| inclination = 6.5013°
| asc_node = 222.74°
| arg_peri = 156.11°
| moid = 0.2354 AU{{·}}91.7 LD
| satellites = 1[5][6][7]{{efn|name=Pravec-2006-figures}}
| dimensions = 0.880 km {{small|(derived)}}[8]
{{val|0.9|0.2}} km[7]{{efn|name=Pravec-2006-figures}}
{{val|0.940|0.21}} {{small|(derived)}}[6]
| rotation = {{val|2.5}} h[11]
{{val|2.51620|0.00003}} h[5]
| albedo = 0.18[7]{{efn|name=Pravec-2006-figures}}
0.20 {{small|(assumed)}}[8]
| spectral_type = SMASS = Sq {{·}}S [8]
B–V = {{val|0.810|0.020}}[5]
V–R = {{val|0.440|0.010}}[5]
V–I = {{val|0.760|0.020}}[5]
| abs_magnitude = 17.3{{·}}{{val|17.64|0.14}}[5][8][23]
}}

{{mp|(31345) 1998 PG}} is an eccentric, stony asteroid and binary system, classified as near-Earth object of the Amor group of asteroids, approximately 900 meters in diameter. It minor-planet moon, S/2001 (31345) 1, has an estimated diameter of 270 meters.

This asteroid was discovered on 3 August 1998, by the Lowell Observatory Near-Earth-Object Search (LONEOS) at Anderson Mesa Station, near Flagstaff, Arizona, United States.[3]

Orbit

{{mp|1998 PG}} orbits the Sun at a distance of 1.2–2.8 AU once every 2 years and 10 months (1,046 days). Its orbit has an eccentricity of 0.39 and an inclination of 7° with respect to the ecliptic. A first precovery was taken at Palomar Observatory in 1978, extending the body's observation arc by 20 years prior to its official discovery observation at Anderson Mesa.[3]

Close approaches

The asteroid has a Earth minimum orbital intersection distance of {{convert|0.2354 |AU |km |abbr=on |lk=off |sigfig=3}}, which translates into approximately 92 lunar distances. It has made multiple close approaches to Earth, with the closest being 35,648,680 kilometers on 15 October 1978. With an aphelion of more than 2.8 AU, {{mp|1998 PG}} is also a Mars-crosser.

Physical characteristics

Spectral type

In the SMASS taxonomy, {{mp|1998 PG}} is classified as a transitional Sq-type, which is an intermediary between the common stony S-type and the less frequent Q-type asteroids.

Diameter and albedo

According to the 2006-published Photometric survey of binary near-Earth asteroids by Petr Pravec and derived data from the Collaborative Asteroid Lightcurve Link and the "Johnston's archive", {{mp|1998 PG}} measures between 880 and 940 meters in diameter and its surface has an albedo of 0.18 and 0.20, respectively.[6][7][8]{{efn|name=Pravec-2006-figures}}

Rotation

In the late 1990s, a rotational lightcurve of {{mp|1998 PG}} was obtained from photometric observations by Hungarian astronomers László Kiss, Gyula Szabó and Krisztián Sárneczky. Lightcurve analysis gave a rotation period of 2.5 hours with a brightness variation of 0.1 magnitude ({{small|U=n.a.}}).[11]

A second lightcurve obtained and published in 2000, by an international collaboration of astronomers gave a rotation period of {{val|2.51620|0.00003}} hours with a brightness amplitude of 0.11 magnitude ({{small|U=2}}).[5]

Moon

During the second photometric observation, it was discovered that {{mp|1998 PG}} is a probable/possible asynchronous binary system with a minor-planet moon orbiting it every 7.0035 hours,[8] or twice this period solution.[6]

The moon's provisional designation is {{mp|S/2001 (31345) 1}}.[6] The system has an estimated secondary-to-primary mean-diameter ratio of more than 0.3,[5]{{efn|name=Pravec-2006-figures}} which translates into a diameter of 270 meter for the satellite.[6] The "Johnston's archive" also estimates that the moon's orbit has a semi-major axis of 1.4 kilometers.[6]

From the surface of {{mp|1998 PG}}, the moon would have an angular diameter of about 16.3°.{{efn|name=calculated}} For comparison, the Sun appears to be 0.5° from Earth.

Numbering and naming

This minor planet was numbered by the Minor Planet Center on 30 November 2001.[40] As of 2018, it has not been named.[3]

Gallery

Notes

{{notelist|refs={{efn|name=calculated|Calculated by solving .}}{{efn|name=Pravec-2006-figures|1=Pravec (2006) Photometric survey of binary near-Earth asteroids, Icarus, 181:63-93. Summary figures: albedo of 0.18; diameter of primary {{val|0.9|0.2}} km; ratio: Ds/Dp of 0.3;. Figures are listed at johnstonsarchive.net}}

}}

References

1. ^1 2 3 4 {{cite web |title = (31345) 1998 PG |work = Minor Planet Center |url = http://www.minorplanetcenter.net/db_search/show_object?object_id=31345 |accessdate = 31 March 2017}}
2. ^1 {{cite web |title = MPC/MPO/MPS Archive |work = Minor Planet Center |url = http://www.minorplanetcenter.net/iau/ECS/MPCArchive/MPCArchive_TBL.html |accessdate = 24 February 2018}}
3. ^1 2 3 4 5 6 7 {{cite web |last1 = Johnston |first1=Robert |title = (31345) 1998 PG |website = johnstonsarchive.net |date = 21 September 2014 |url = http://www.johnstonsarchive.net/astro/astmoons/am-31345.html |accessdate = 31 March 2017}}
4. ^1 2 3 4 5 6 {{cite web |title = LCDB Data for (31345) |publisher = Asteroid Lightcurve Database (LCDB) |url = http://www.minorplanet.info/PHP/GenerateALCDEFPage_Local.php?AstInfo=31345%7C |accessdate = 31 March 2017}}
5. ^1 2 {{Cite journal |first1 = L. L. |last1 = Kiss |first2 = Gy. |last2 = Szabó |first3 = K. |last3 = Sárneczky |date = November 1999 |title = CCD photometry and new models of 5 minor planets |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=1999A&AS..140...21K |journal = Astronomy and Astrophysics Supplement |pages = 21–28 |bibcode = 1999A&AS..140...21K |doi = 10.1051/aas:1999115 |arxiv = astro-ph/9909159 |access-date= 31 March 2017}}
6. ^1 2 3 4 5 6 7 8 {{Cite journal |display-authors = 6 |first1 = Petr |last1 = Pravec |first2 = Lenka |last2 = Sarounová |first3 = David L. |last3 = Rabinowitz |first4 = Michael D. |last4 = Hicks |first5 = Marek |last5 = Wolf |first6 = Yurij N. |last6 = Krugly |first7 = Fiodor P. |last7 = Velichko |first8 = Vasilij G. |last8 = Shevchenko |first9 = Vasilij G. |last9 = Chiorny |first10 = Ninel M. |last10 = Gaftonyuk |first11 = Guy |last11 = Genevier |date = July 2000 |title = Two-Period Lightcurves of 1996 FG 3, 1998 PG, and (5407) 1992 AX: One Probable and Two Possible Binary Asteroids |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2000Icar..146..190P |journal = Icarus |volume = 146 |issue = 1 |pages = 190–203 |bibcode = 2000Icar..146..190P |doi = 10.1006/icar.2000.6375 |access-date= 31 March 2017}}
7. ^1 2 3 4 {{Cite journal |display-authors = 6 |first1 = P. |last1 = Pravec |first2 = P. |last2 = Scheirich |first3 = P. |last3 = Kusnirák |first4 = L. |last4 = Sarounová |first5 = S. |last5 = Mottola |first6 = G. |last6 = Hahn |first7 = P. |last7 = Brown |first8 = G. |last8 = Esquerdo |first9 = N. |last9 = Kaiser |first10 = Z. |last10 = Krzeminski |first11 = D. P. |last11 = Pray |first12 = B. D. |last12 = Warner |first13 = A. W. |last13 = Harris |first14 = M. C. |last14 = Nolan |first15 = E. S. |last15 = Howell |first16 = L. A. M. |last16 = Benner |first17 = J.-L. |last17 = Margot |first18 = A. |last18 = Galád |first19 = W. |last19 = Holliday |first20 = M. D. |last20 = Hicks |first21 = Yu. N. |last21 = Krugly |first22 = D. |last22 = Tholen |first23 = R. |last23 = Whiteley |first24 = F. |last24 = Marchis |first25 = D. R. |last25 = DeGraff |first26 = A. |last26 = Grauer |first27 = S. |last27 = Larson |first28 = F. P. |last28 = Velichko |first29 = W. R. |last29 = Cooney |first30 = R. |last30 = Stephens |first31 = J. |last31 = Zhu |first32 = K. |last32 = Kirsch |first33 = R. |last33 = Dyvig |first34 = L. |last34 = Snyder |first35 = V. |last35 = Reddy |first36 = S. |last36 = Moore |first37 = S. |last37 = Gajdos |first38 = J. |last38 = Világi |first39 = G. |last39 = Masi |first40 = D. |last40 = Higgins |first41 = G. |last41 = Funkhouser |first42 = B. |last42 = Knight |first43 = S. |last43 = Slivan |first44 = R. |last44 = Behrend |first45 = M. |last45 = Grenon |first46 = G. |last46 = Burki |first47 = R. |last47 = Roy |first48 = C. |last48 = Demeautis |first49 = D. |last49 = Matter |first50 = N. |last50 = Waelchli |first51 = Y. |last51 = Revaz |first52 = A. |last52 = Klotz |first53 = M. |last53 = Rieugné |first54 = P. |last54 = Thierry |first55 = V. |last55 = Cotrez |first56 = L. |last56 = Brunetto |first57 = G. |last57 = Kober |date = March 2006 |title = Photometric survey of binary near-Earth asteroids |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2006Icar..181...63P |journal = Icarus |volume = 181 |issue = 1 |pages = 63–93 |bibcode = 2006Icar..181...63P |doi = 10.1016/j.icarus.2005.10.014 |access-date= 31 March 2017}}
8. ^1 {{Cite journal |first1 = Petr |last1 = Pravec |first2 = Alan W. |last2 = Harris |first3 = Peter |last3 = Kusnirák |first4 = Adrián |last4 = Galád |first5 = Kamil |last5 = Hornoch |date = September 2012 |title = Absolute magnitudes of asteroids and a revision of asteroid albedo estimates from WISE thermal observations |url = http://adsabs.harvard.edu/cgi-bin/bib_query?bibcode=2012Icar..221..365P |journal = Icarus |volume = 221 |issue = 1 |pages = 365–387 |bibcode = 2012Icar..221..365P |doi = 10.1016/j.icarus.2012.07.026 |access-date= 31 March 2017}}
[1][2][3][4][5][6][7][8]

}}

External links

  • MPEC 1998-P13 : 1998 PG, Minor Planet Electronic Circular 6 August 1998
  • [https://web.archive.org/web/20170331211703/http://earn.dlr.de/nea/031345.htm (31345) 1998 PG] at E.A.R.N. – European Asteroid Research Node
  • Asteroids with Satellites, Robert Johnston, johnstonsarchive.net
  • Binary and Ternary Near-Earth Asteroids Detected by Radar, Lance Benner, JPL
  • Asteroid Lightcurve Database (LCDB), query form (info)
  • [https://books.google.com/books?id=aeAg1X7afOoC&pg Dictionary of Minor Planet Names], Google books
  • Asteroids and comets rotation curves, CdR – Observatoire de Genève, Raoul Behrend
  • Discovery Circumstances: Numbered Minor Planets (30001)-(35000) – Minor Planet Center
  • {{JPL small body|id=31345}}
{{Minor planets navigator |number=31345 }}{{Small Solar System bodies}}{{DEFAULTSORT:031345}}

5 : Amor asteroids|Discoveries by LONEOS|Binary asteroids|Sq-type asteroids (SMASS)|Astronomical objects discovered in 1998
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