Hái-ông-chheⁿ (海王星, Eng-gí: Neptune) sī lī Ji̍t-thaû tē 8 hn̄g ê he̍k-chheⁿ, m̄-koh sam-sî ē chaú kah tē 9 hn̄g khì, in-ūi Mê-ông-chheⁿ ê kúi-tō ū khah te̍k-sû. I mā si Thài-iông-hē siōng goā-khaú, siōng sè lia̍p ê khì-thé toā he̍k-chheⁿ (gas giant). Sè bóng sè, Hái-ông-chheⁿ ê chit-liōng khah chē Thiⁿ-ông-chheⁿ, in-ūi tāng-le̍k-tiûⁿ (gravitational field) tì-sú i ê bi̍t-tō͘ ū khah koân.

Hái-ông-chheⁿ ♆
Hoat-kiàn
Hoat-kiàn-chiá
Hoat-kiàn ji̍t-chí 23 September 1846
Miâ-hō
Hō-miâ iû-lâi
Latin Neptūnus, via French Neptune
Kúi-tō sèng-chit
Goân-kî J2000
Aphelion 30.33 astronomical units (4.54×10^9 km)
Kīn-ji̍t-tiám 29.81 astronomical units (4.46×10^9 km)
30.07 astronomical units (4.50×10^9 km)
Lî-sim-lu̍t 0.008678
367.49 days
5.43 km/s
256.228°
Khi-pêng 1.767975° to ecliptic
6.43° to Sun's equator
0.72° to invariable plane
131.784°
2042-Sep-04
276.336°
Known satellites 14
Bu̍t-lí sèn-chit
Pêng-kin poàn-kéng
24,622±19 km
Chhiah-tō poàn-kéng
24,764±15 km
3.883 Earths
Ke̍k-tē poàn-kéng
24,341±30 km
3.829 Earths
Píⁿ-pêⁿ-lu̍t 0.0171±0.0013
7.6183×109 km2
14.98 Earths
Thé-chek 6.254×1013 km3
57.74 Earths
Chit-liōng 1.02413×1026 kg
17.147 Earths
5.15×10-5 Suns
Pêng-kin bi̍t-tō͘
1.638 g/cm3
11.15 m/s2
1.14 g
0.23 (estimate)
23.5 km/s
Hêng-chheⁿ chū-choán chiu-kî
0.6713 day
16 h 6 min 36 s
Chhiah-tō chū-choán sok-tō͘
2.68 km/s (9,650 km/h)
28.32° (to orbit)
Pak-ke̍k chhiah-keng
19h 57m 20s
299.3°
Pak-ke̍k chhiah-hūi
42.950°
Hoán-siā-lu̍t 0.290 (bond)
0.442 (geom.)
Piáu-bīn un-tō͘ siōng-kē pêng-kin siōng-koân
1 bar level 72 K (−201 °C)
0.1 bar (10 kPa) 55 K (−218 °C)
7.67 to 8.00
2.2–2.4″
Tāi-khì-khoan
19.7±0.6 km
Thé-chek cho͘-sêng

Hái-ông-chheⁿ ê miâ-jī sī toè Lô-má hái-sîn lâi--ê. Tāi-piáu hû-hō sī hái-sîn ê bú-khì saⁿ-chhe-kek (trident) . 1846 nî 9 goe̍h 23 hông hoat-hiān. 1989 nî 8 goe̍h 25, Voyager 2 ùi i piⁿ--á poe koè.

Chit lia̍p nâ-sek ê he̍k-chheⁿ chhan-chhiūⁿ Thó͘-chheⁿ mā ū khoân, khah bô ióng-kò͘ tō sī. Voyager 2 hoat-kak chiah-ê khoân ê kiat-kò͘ mā kài oân-chéng. Hái-ông-chheⁿ téng-koân ê hong-sok ē-tit kaù kah 2,000 km/h. Khong-khì lāi-té ū H₂, (hydrogen), He₂ (helium), kap CH₄ (methane, chiau-khì) hō͘ i khoàⁿ--khí-laî nâ-nâ. 1989 nî Voyager 2 poe koè ê sî khoàⁿ tio̍h i ê lâm-poàⁿ-kiû ū 1 ê Toā-o͘-tiám (Great Dark Spot), bē-su Bo̍k-ông-chheⁿ ê Toā-âng-tiám, m̄-koh boé-chhiú soah bô--khì. Hái-ông-chheⁿ ū 13 lia̍p oē-chheⁿ, lāi-té 5 lia̍p iáu ū koá cheng-gī. Siōng toā lia̍p ê oē-chheⁿ Triton chin sim-sek, tò-thaû-hiòng ê kúi-tō, Thài-iông-hē siōng-kài léng (38K) ê chheⁿ-thé, N₂ (nitrogen, chit-sò͘) kap CH₄ kò͘-sêng ê tāi-khì-chân po̍h-po̍h-po̍h (14 microbar).

Goā-pō͘ liân-kiat

siu-kái
Thài-iông-hē
 
Chheⁿ: Ji̍t-thâu
He̍k-chheⁿ: Chúi-chheⁿ | Kim-chheⁿ | Tē-kiû | Hóe-chheⁿ | Bo̍k-chheⁿ | Thó͘-chheⁿ | Thian-ông-chheⁿ | Hái-ông-chheⁿ
É-he̍k-chheⁿ: Ceres | Mê-ông-chheⁿ | Haumea | Makemake | Eris
Sió-bu̍t-thé: Sió-he̍k-chheⁿ | Hái-ông-chheⁿ goā chheⁿ-thé | Tn̂g-boé-chheⁿ
Oē-chheⁿ: Goe̍h-niû | Hoé-chheⁿ ê | Bo̍k-chheⁿ ê | Thó͘-chheⁿ ê | Thian-ông-chheⁿ ê | Hái-ông-chheⁿ ê
Tīn: Sió-he̍k-chheⁿ-toà | Kuiper-toà | Sàn-loān îⁿ-poâⁿ | Oort-hûn
Chhiáⁿ chham-khó thian-bûn bu̍t-thé, thài-iông-hē ê chheⁿ-thé lia̍t-toaⁿ, chiàu poàⁿ-kèng pâi iah sī chiàu chit-liōng pâi