### Pehea e hoʻoholo ai i ka makahiki o kahi hōkū
He nui nā hōkū i hoʻopuehu ʻia ma ko kākou galaxy a me nā mea e pili ana. ʻO ka hoʻoholo ʻana i nā makahiki o nā hōkū kekahi o nā pilikia i ka astrophysics, akā ua hāʻawi mai nā ʻano ʻepekema paʻakikī i nā ala e wehe ai i kā lākou mau mea huna. Ma kēia ʻatikala, e kūkākūkā mākou i nā ʻano hana mua a nā astronomers e hoʻohana ai e hoʻoholo i nā makahiki o nā hōkū a me ke koʻikoʻi o kēia ʻike i ka hoʻomaopopo ʻana i ka ulu ʻana o nā hōkū a me nā galaxies.
#### 1. Hertzsprung-Russell (HR).
ʻO ke kiʻikuhi Hertzsprung-Russell kahi mea hana koʻikoʻi i ka astrophysics no ka hoʻopili ʻana i ka mahana o kahi hōkū i kona luminosity (kona ʻōlinolino). Hoʻohui kēia kiʻikuhi i nā hōkū ma muli o kā lākou papa spectral (i hoʻoholo ʻia e ka mahana) a me ka luminosity. Ma ke kiʻikuhi HR, ua māhele ʻia nā hōkū i kekahi mau pūʻulu, e like me nā hōkū moʻo nui, nā pilikua ʻulaʻula, a me nā dwarf keʻokeʻo.
– Nā Moʻo Nui a me ka Noiʻi Makahiki:
Puhi nā hōkū moʻo nui i ka hydrogen i loko o ko lākou mau kikowaena. ʻO ke kaumaha o kahi hōkū moʻo nui e hoʻoholo i kona kūlana ma ka kiʻikuhi HR. Ma muli o ka pili ʻana o ke kaumaha me ka wikiwiki o ka puhi ʻana o ka hydrogen a me ke ola o kahi hōkū moʻo nui, hiki i nā mea kilo hōkū ke kuhi i ka makahiki o kahi hōkū ma ke ana ʻana i kona mahana a me ka mālamalama.
– Nā Pae Hoʻomohala Hōkū:
Ke pau ka hydrogen i loko o ko lākou mau kikowaena, haʻalele kēia mau hōkū i ke kaʻina nui, e lilo i mau pilikua ʻulaʻula a laila nā dwarf keʻokeʻo. Hāʻawi nā kūlana o nā hōkū ma nā pae evolutionary like ʻole ma ka HR Diagram i kahi hōʻailona i ko lākou mau makahiki.
#### 2. Nā Isochrones
ʻO nā Isochrons he mau laina kuhiakau ma ka HR Diagram e hoʻohui ana i nā hōkū o ka makahiki like akā nā nui like ʻole. Ma ka hoʻolālā ʻana i nā isochrones no nā makahiki like ʻole, hiki i nā mea kilo hōkū ke hoʻohālikelike i nā nānā ʻana o nā hui hōkū a i ʻole nā heluna hōkū me nā isochrones theoretical.
– Nānā ʻana i ka Hui Hōkū:
He mea pono loa nā hui hōkū no ka hoʻopaʻa inoa ʻana, no ka mea, ua manaʻo ʻia ua hoʻokumu ʻia nā hōkū i loko o ka hui i ka manawa like. Ma ka nānā ʻana i ke kiʻikuhi HR o ka hui a me ka hoʻohālikelike ʻana iā ia me nā isochrones, hiki i nā mea kilo hōkū ke kuhi i ka makahiki o ka hui, a pēlā hoʻi nā makahiki o nā hōkū i loko.
#### 3. ʻIke Nukleokosmokronika
Pili ka nucleocosmochronology i ke ana ʻana i ka lakio o nā isotopes radioactive a me kā lākou huahana palaho i loko o kahi hōkū e koho i kona mau makahiki. ʻO nā isotopes maʻamau i hoʻohana ʻia ma kēia ʻano hana e komo pū me ka uranium-238, thorium-232, a me samarium-147.
- Kaʻina hana:
Ma ke ana ʻana i nā lakio o nā isotopes like ʻole, hiki i nā kānaka ʻepekema ke hoʻoholo i ka lōʻihi o ke kaʻina hana palaho, a laila hiki ke pili i ka makahiki o ka hōkū. Ua like kēia ʻano hana me ke ʻano o ka hoʻohana ʻana i ka helu kalapona e hoʻoholo ai i ka makahiki o nā mōʻalihaku ma ka Honua, akā ma kahi pae nui aʻe a no nā mea like ʻole.
#### 4. Nā Hoʻoneʻe Hōkū (Astroseismology)
ʻO ka Astroseismology ke aʻo ʻana i nā oscillations (nā haʻalulu) i loko o nā hōkū, e like me ke aʻo ʻana o nā ōlaʻi i loko o ka Honua. Hoʻokumu kēia mau oscillations i nā ʻokoʻa liʻiliʻi i ka luminosity a me ka spectrum o ka hōkū, hiki ke ana ʻia me nā telescopes pololei loa.
– ʻIke Kūloko o ka Hōkū:
Hiki i kēia mau ʻano haʻalulu ke haʻi i nā mea kilo hōkū e pili ana i ke ʻano o loko o ka hōkū, me kona hoʻolaha nuipa, ka wikiwiki o ka wili ʻana, a me ka haku mele kemika. Ma ka hoʻomaopopo ʻana i kēia ʻano o loko, hiki iā lākou ke kuhi i ka makahiki o ka hōkū.
#### 5. Ka Mana o nā Māhele Magnetic a me nā Makani Hōkū
Hiki ke hoʻohana ʻia nā kahua makeneka a me nā makani hōkū ma ke ʻano he mau hōʻailona o ka makahiki o kahi hōkū. ʻO nā hōkū me nā nui haʻahaʻa e loaʻa pinepine i nā kahua makeneka ikaika a me nā makani hōkū, hiki ke hōʻemi i ko lākou wikiwiki wili i ka hala ʻana o ka manawa.
– Hana Makeneka:
Ke emi nei ka pae o ka hana magnetic (e like me nā kiko hōkū a me nā lapalapa) i ka wā e ʻelemakule ai kahi hōkū, ʻoiai e lohi ana hoʻi kona wili ʻana. Ma ke ana ʻana i ka wikiwiki o ka wili ʻana a me ka hana magnetic, hiki i nā kilo hōkū ke kuhi i ka makahiki o ka hōkū.
#### 6. Ka Hoʻoheheʻe ʻia ʻana o ka Metala
ʻO ke ʻano metallicity e pili ana i ka nui o nā mea i kaumaha ma mua o ka helium i loko o kahi hōkū. ʻO nā hōkū i hoʻokumu mua ʻia i ke ao holoʻokoʻa he haʻahaʻa ko lākou metallicity, no ka mea, ʻo ka hapa nui o nā mea kaumaha i hoʻokumu ʻia i ka hanauna mua o nā hōkū a laila hana hou ʻia i loko o ka lewa interstellar ma o nā supernovae.
– Pilina o ka Wā Metala:
ʻAʻole hōʻike pololei ka nānā ʻana i ka metallicity i ka makahiki o kahi hōkū, akā hiki iā ia ke kōkua i ke kau ʻana i kahi hōkū i loko o ka pōʻaiapili e pili ana i nā hōkū ʻē aʻe. ʻOi aku ka ʻelemakule o nā hōkū me nā metallicities haʻahaʻa ma mua o nā hōkū me nā metallicities kiʻekiʻe.
#### Hopena
He paʻakikī multidisciplinary ka hoʻoholo ʻana i ka makahiki o nā hōkū i loko o ka astrophysics. Ma ka hoʻohana ʻana i nā ʻano hana e like me nā kiʻikuhi HR, isochrones, nucleocosmochronology, astroseismology, nā mana o ke kahua magnetic, a me ka metallicity, hiki i nā astronomers ke hōʻiliʻili i ka ʻike koʻikoʻi e pili ana i nā makahiki o nā hōkū. ʻAʻole wale kēia ʻike he mea nui no ka hoʻomaopopo ʻana i nā hōkū pākahi akā hāʻawi pū kekahi i kahi ʻike ākea o ka ulu ʻana o nā galaxies holoʻokoʻa, me ko mākou home, ʻo ka Milky Way. Ke hoʻomau nei ka hoʻomaʻemaʻe ʻia ʻana o ka hui pū ʻana o kēia mau ʻano hana ma o ka noiʻi a me ka ʻenehana hou, e hoʻokokoke mai ana iā mākou i ka hoʻomaopopo ʻana i nā pōʻaiapuni ola paʻakikī a hoihoi o nā hōkū.
