वरुणग्रह
वरुणग्रह (प्रतीक: ) सौर्यमण्डलको सूर्यबठेहै आठौं ग्रह हो। यो ग्रह लै एक ग्यास् पिण्ड हो जइका वरिपरि चारवटा मुस्किलले धेखिन्या खालका घेराअन छन्। Urbain Le Verrier र John Couch Adams लाई वरुण ग्रहको आविश्कारकको रूपमी चिनिन्छ। ये ग्रहलाई पृथ्वीबठे बाइनाकुलर रे दूरदर्शकयन्त्रका मद्दतले सजिलै हेद्दु सकिन्छ। भोयजर २ नामक अन्तरिक्षयानले सन् १९८९ माई पत्तालगाया अनसार येईमा "The Dark Spot" नाम गर्याको आँधी रयाः छ। यद्यपी सन् १९९४ माइ उक्त आँधी धेखिया थिएन्। बरुण ग्रहका १३ वटा उपग्रहअन छन्। ती मध्ये सबैहै ठूलो उपग्रह Triton हो, जो उपग्रह वरुणग्रहको एकमात्र गोलो उपग्रह हो। Trition पृथ्वीको चन्द्रमा है केही नानो छ। अङ्ग्रेजीमाइ येईलाई नेप्च्युन भणिन्छ, नेप्च्युन, प्राचीन रोमन धर्मको प्रमुख देवताअन मध्ये एउटा थ्यो। उनी समुद्रका देवता थ्याः। उनकै समतुल्य प्राचीन यूनानी धर्मका देवता थ्याः पोसाइडन। उनराइ नामबठेहइ सौर्य परिवारको आठौँ ग्रहको नाम नेप्च्युन राखियाः हो।
Neptune from Voyager 2 with Great Dark Spot at left | |||||||||||||||||||||
Discovery | |||||||||||||||||||||
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Discovered by | Urbain Le Verrier John Couch Adams Johann Galle | ||||||||||||||||||||
Discovery date | September 23, 1846[1] | ||||||||||||||||||||
Designations | |||||||||||||||||||||
Pronunciation | Walter, Elizabeth (April 21, 2003). Cambridge Advanced Learner's Dictionary (2nd ed.). Cambridge University Press. ISBN 0-521-53106-3.</ref> | ||||||||||||||||||||
Adjectives | Neptunian | ||||||||||||||||||||
Orbital characteristics[2][3] | |||||||||||||||||||||
Epoch J2000 | |||||||||||||||||||||
Aphelion | 4,553,946,490 km 30.44125206 AU | ||||||||||||||||||||
Perihelion | 4,452,940,833 km 29.76607095 AU | ||||||||||||||||||||
Semi-major axis | 4,503,443,661 km 30.10366151 AU | ||||||||||||||||||||
Eccentricity | 0.011214269 | ||||||||||||||||||||
Orbital period | 60,190[4] days 164.79 years 89,666 Neptune solar days[5] | ||||||||||||||||||||
Synodic period | 367.49 day[6] | ||||||||||||||||||||
Average orbital speed | 5.43 km/s[6] | ||||||||||||||||||||
Mean anomaly | 267.767281° | ||||||||||||||||||||
Inclination | 1.767975° to Ecliptic 6.43° to Sun’s equator 0.72° to Invariable plane[7] | ||||||||||||||||||||
Longitude of ascending node | 131.794310° | ||||||||||||||||||||
Argument of perihelion | 265.646853° | ||||||||||||||||||||
Known satellites | 13 | ||||||||||||||||||||
Physical characteristics | |||||||||||||||||||||
Equatorial radius | 24,764 ± 15 km[8][9] 3.883 Earths | ||||||||||||||||||||
Polar radius | 24,341 ± 30 km[8][9] 3.829 Earths | ||||||||||||||||||||
Flattening | 0.0171 ± 0.0013 | ||||||||||||||||||||
Surface area | 7.6408×109 km2[4][9] 14.98 Earths | ||||||||||||||||||||
Volume | 6.254×1013 km3[6][9] 57.74 Earths | ||||||||||||||||||||
Mass | 1.0243×1026 kg[6] 17.147 Earths | ||||||||||||||||||||
Mean density | 1.638 g/cm3[6][9] | ||||||||||||||||||||
Surface gravity | 11.15 m/s2[6][9] 1.14 g | ||||||||||||||||||||
Escape velocity | 23.5 km/s[6][9] | ||||||||||||||||||||
Sidereal rotation period | 0.6713 day[6] 16 h 6 min 36 s | ||||||||||||||||||||
Equatorial rotation velocity | 2.68 km/s 9,660 km/h | ||||||||||||||||||||
Axial tilt | 28.32°[6] | ||||||||||||||||||||
North pole right ascension | ढाँचा:RA[8] 299.3° | ||||||||||||||||||||
North pole declination | 42.950°[8] | ||||||||||||||||||||
Albedo | 0.290 (bond) 0.41 (geom.)[6] | ||||||||||||||||||||
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Apparent magnitude | 8.02 to 7.78[6][10] | ||||||||||||||||||||
Angular diameter | 2.2″–2.4″[6][10] | ||||||||||||||||||||
Atmosphere[6] | |||||||||||||||||||||
Scale height | 19.7 ± 0.6 km | ||||||||||||||||||||
Composition by volume |
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सन्दर्भअन
- Hamilton, Calvin J. (August 4, 2001). "Neptune". Views of the Solar System. Retrieved 2007-08-13.
- Yeomans, Donald K. (July 13, 2006). "HORIZONS System". NASA JPL. Retrieved 2007-08-08.—At the site, go to the "web interface" then select "Ephemeris Type: Elements", "Target Body: Neptune Barycenter" and "Center: Sun".
- Orbital elements refer to the barycentre of the Neptune system, and are the instantaneous osculating values at the precise J2000 epoch. Barycentre quantities are given because, in contrast to the planetary centre, they do not experience appreciable changes on a day-to-day basis from to the motion of the moons.
- Seligman, Courtney. "Rotation Period and Day Length". Retrieved 2009-08-13.
- Williams, David R. (September 1, 2004). "Neptune Fact Sheet". NASA. Retrieved 2007-08-14.
- "The MeanPlane (Invariable plane) of the Solar System passing through the barycenter". 2009-04-03. Archived from the original on 2009-04-20. Retrieved 2009-04-10. (produced with Solex 10 written by Aldo Vitagliano; see also Invariable plane)
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P. Kenneth, Seidelmann (2007). "Report of the IAU/IAGWorking Group on cartographic coordinates and rotational elements". Celestial Mechanics and Dynamical Astronomy. 90 (3): 155–180. doi:10.1007/s10569-007-9072-y. Unknown parameter
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