Albedo geometri - Wikipedia Bahasa Melayu, ensiklopedia bebas

Dalam bidang astronomi, albedo geometri sesebuah objek samawi merujuk kepada nisbah kecerahan sebenar seperti yang dilihat daripada sumber cahaya (iaitu pada sudut fasa sifar) kepada sesebuah cakera yang secara idealnya rata, terpantul penuh, terserak baur (pantulan Lambert) dengan keratan rentas yang sama. (Sudut fasa ini merujuk kepada arah laluan cahaya dan bukan sudut fasa dalam pengertian biasa dalam bidang optik mahupun elektronik.)

Penyerakan baur menandakan bahawa sinaran terpantul secara isotropik tanpa mempunyai ingatan lokasi sumber cahaya kejadian. Sudut fasa sifar berpadanan dengan penglihatan sepanjang arah pencahayaan. Bagi pemerhati yang terikat pada Bumi, hal ini berlaku apabila jasad yang dimaksudkan berada pada kedudukan istiqbal dan pada kedudukan ekliptik.

Albedo geometri visual merujuk kepada kuantiti albedo geometri apabila mengira hanya sinaran elektromagnet dalam spektrum tampak.

Contoh

Albedo geometri mungkin lebih besar atau lebih kecil daripada albedo Bond, bergantung pada sifat permukaan dan atmosfera jasad berkenaan. Antara beberapa contoh adalah seperti berikut:^[1]

Nama jasad	Albedo Bond		Albedo geometri visual
Utarid^[2]^[3]	0.088	0.088	0.142	0.142
Zuhrah^[4]^[3]	0.76	0.76	0.689	0.689
Bumi^[5]^[3]	0.294	0.294	0.434	0.434
Bulan^[6]	0.11	0.11	0.12	0.12
Marikh^[7]^[3]	0.25	0.25	0.17	0.17
Musytari^[8]^[3]	0.503	0.503	0.538	0.538
Zuhal^[9]^[3]	0.342	0.342	0.499	0.499
Enceladus^[10]^[11]	0.81	0.81	1.38	1.38
Uranus^[12]^[3]	0.300	0.3	0.488	0.488
Neptun^[13]^[3]	0.290	0.29	0.442	0.442
Pluto	0.4	0.4	0.44–0.61	0.44
Eris^[14]	0.99	0.99	0.96	0.96

Lihat juga

Albedo
Anisotropi
Albedo Bond
Pantulan Lambert

Rujukan

^ Albedo of the Earth
^ Mallama, Anthony (2017). "The spherical bolometric albedo for planet Mercury". arXiv:1703.02670 [astro-ph.EP].
^ ^a ^b ^c ^d ^e ^f ^g ^h Mallama, Anthony; Krobusek, Bruce; Pavlov, Hristo (2017). "Comprehensive wide-band magnitudes and albedos for the planets, with applications to exo-planets and Planet Nine". Icarus. 282: 19–33. arXiv:1609.05048. Bibcode:2017Icar..282...19M. doi:10.1016/j.icarus.2016.09.023. S2CID 119307693.
^ Haus, R.; dll. (July 2016). "Radiative energy balance of Venus based on improved models of the middle and lower atmosphere" (PDF). Icarus. 272: 178–205. Bibcode:2016Icar..272..178H. doi:10.1016/j.icarus.2016.02.048.
^ Williams, David R. (2024-11-15). "Earth Fact Sheet". NASA. Dicapai pada 2025-01-02.
^ Williams, David R. (2014-04-25). "Moon Fact Sheet". NASA. Dicapai pada 2015-03-02.
^ Mars Fact Sheet, NASA
^ Li, Liming; dll. (2018). "Less absorbed solar energy and more internal heat for Jupiter". Nature Communications. 9 (1): 3709. Bibcode:2018NatCo...9.3709L. doi:10.1038/s41467-018-06107-2. PMC 6137063. PMID 30213944.
^ Hanel, R.A.; dll. (1983). "Albedo, internal heat flux, and energy balance of Saturn". Icarus. 53 (2): 262–285. Bibcode:1983Icar...53..262H. doi:10.1016/0019-1035(83)90147-1.
^ Howett, Carly J. A.; Spencer, John R.; Pearl, J. C.; Segura, M. (2010). "Thermal inertia and bolometric Bond albedo values for Mimas, Enceladus, Tethys, Dione, Rhea and Iapetus as derived from Cassini/CIRS measurements". Icarus. 206 (2): 573–593. Bibcode:2010Icar..206..573H. doi:10.1016/j.icarus.2009.07.016.
^ See the discussion here for explanation of this unusual value above one.
^ Pearl, J.C.; dll. (1990). "The albedo, effective temperature, and energy balance of Uranus, as determined from Voyager IRIS data". Icarus. 84 (1): 12–28. Bibcode:1990Icar...84...12P. doi:10.1016/0019-1035(90)90155-3.
^ Pearl, J.C.; dll. (1991). "The albedo, effective temperature, and energy balance of Neptune, as determined from Voyager data". J. Geophys. Res. 96: 18, 921–18, 930. Bibcode:1991JGR....9618921P. doi:10.1029/91JA01087.
^ Verbiscer, Anne J.; Helfenstein, Paul; Porter, Simon B.; Benecchi, Susan D.; Kavelaars, J. J.; Lauer, Tod R.; et al. (April 2022). "The Diverse Shapes of Dwarf Planet and Large KBO Phase Curves Observed from New Horizons". The Planetary Science Journal. 3 (4): 31. Bibcode:2022PSJ.....3...95V. doi:10.3847/PSJ/ac63a6.

Bacaan lanjut

NASA JPL glossary
K.P. Seidelmann, Ed. (1992) Explanatory Supplement to the Astronomical Almanac, University Science Books, Mill Valley, California.

[1] Albedo of the Earth

[Mallama-2] Mallama, Anthony (2017). "The spherical bolometric albedo for planet Mercury". arXiv:1703.02670 [astro-ph.EP].

[Mallama_et_al-3] ^ ^a ^b ^c ^d ^e ^f ^g ^h Mallama, Anthony; Krobusek, Bruce; Pavlov, Hristo (2017). "Comprehensive wide-band magnitudes and albedos for the planets, with applications to exo-planets and Planet Nine". Icarus. 282: 19–33. arXiv:1609.05048. Bibcode:2017Icar..282...19M. doi:10.1016/j.icarus.2016.09.023. S2CID 119307693.

[Haus_et_al-4] Haus, R.; dll. (July 2016). "Radiative energy balance of Venus based on improved models of the middle and lower atmosphere" (PDF). Icarus. 272: 178–205. Bibcode:2016Icar..272..178H. doi:10.1016/j.icarus.2016.02.048.

[earth_fact_sheet-5] Williams, David R. (2024-11-15). "Earth Fact Sheet". NASA. Dicapai pada 2025-01-02.

[moon_fact_sheet-6] Williams, David R. (2014-04-25). "Moon Fact Sheet". NASA. Dicapai pada 2015-03-02.

[7] Mars Fact Sheet, NASA

[Li_et_al-8] Li, Liming; dll. (2018). "Less absorbed solar energy and more internal heat for Jupiter". Nature Communications. 9 (1): 3709. Bibcode:2018NatCo...9.3709L. doi:10.1038/s41467-018-06107-2. PMC 6137063. PMID 30213944.

[Hanel_et_al-9] Hanel, R.A.; dll. (1983). "Albedo, internal heat flux, and energy balance of Saturn". Icarus. 53 (2): 262–285. Bibcode:1983Icar...53..262H. doi:10.1016/0019-1035(83)90147-1.

[10] Howett, Carly J. A.; Spencer, John R.; Pearl, J. C.; Segura, M. (2010). "Thermal inertia and bolometric Bond albedo values for Mimas, Enceladus, Tethys, Dione, Rhea and Iapetus as derived from Cassini/CIRS measurements". Icarus. 206 (2): 573–593. Bibcode:2010Icar..206..573H. doi:10.1016/j.icarus.2009.07.016.

[11] See the discussion here for explanation of this unusual value above one.

[Pearl_et_al_Uranus-12] Pearl, J.C.; dll. (1990). "The albedo, effective temperature, and energy balance of Uranus, as determined from Voyager IRIS data". Icarus. 84 (1): 12–28. Bibcode:1990Icar...84...12P. doi:10.1016/0019-1035(90)90155-3.

[Pearl_et_al_Neptune-13] Pearl, J.C.; dll. (1991). "The albedo, effective temperature, and energy balance of Neptune, as determined from Voyager data". J. Geophys. Res. 96: 18, 921–18, 930. Bibcode:1991JGR....9618921P. doi:10.1029/91JA01087.

[14] Verbiscer, Anne J.; Helfenstein, Paul; Porter, Simon B.; Benecchi, Susan D.; Kavelaars, J. J.; Lauer, Tod R.; et al. (April 2022). "The Diverse Shapes of Dwarf Planet and Large KBO Phase Curves Observed from New Horizons". The Planetary Science Journal. 3 (4): 31. Bibcode:2022PSJ.....3...95V. doi:10.3847/PSJ/ac63a6.

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