suspected planetary nebulae, assuming that a planetary nebula has a spectral signature which can easy be recognised. For the present catalogue, a list of

解釋氫的持續存在或觀察到的能量。依據阿卡維所說，此一發現需要改進現有的爆炸場景或開發新的方案，必須可以： 產生相同的光譜特徵（英语：Spectral signature），作為II-P超新星的共通性，但進化的速度因數放慢6-10倍。 提供延長光變曲線的係數為6倍，同時不會引入窄線光譜特徵或強無線電和X射線發射陳述的星周包層交互作用。

  Houk, Nancy; Smith-Moore, M. Michigan catalogue of two-dimensional spectral types for the HD stars 4. Ann Arbor: Dept. of Astronomy, University of

Bibcode:1969ApJ...156..853A, doi:10.1086/150019  Prinja, R. K.; Massa, D. L., Signature of wide-spread clumping in B supergiant winds, Astronomy and Astrophysics

Kirkpatrick, J. Davy; Henry, Todd J.; McCarthy, Donald W. Jr. A standard stellar spectral sequence in the red/near-infrared - Classes K5 to M9. Astrophysical Journal