supernovae – British Astronomical Association https://britastro.org Supporting amateur astronomers since 1890 Wed, 04 Feb 2026 17:18:12 +0000 en-GB hourly 1 https://wordpress.org/?v=6.4.2 Why do only Type 1a supernovae have Silicon absorption lines in their spectra? https://britastro.org/forums/topic/why-do-only-type-1a-supernovae-have-silicon-absorption-lines-in-their-spectra Wed, 04 Feb 2026 17:18:12 +0000 https://britastro.org/forums/topic/why-do-only-type-1a-supernovae-have-silicon-absorption-lines-in-their-spectra