Stargazing What is the difference between a type IIP and type IIL supernova?

[davenn]

Supernova in M66 in Leo, announced 30/5/2016: https://Earth'sky.org/todays-image/supernova-erupts-in-m66

cheers
Dave

 

[davenn]

just wish I had a scope that could produce a pic like that

 

[|Glitch|]

Thanks for the image, but I am a bit confused. According to the Astronomer's Telegram they have already come to the conclusion that it is a type IIP SN even before it has reached peak brightness.

We obtained an optical spectrum (range 350-910 nm) of ASASSN-16fq/SN 2016cok (ATel#9091) on UT May 28.63 2016 with the 2.4-m telescope (+YFOSC) at LiJiang Gaomeigu Station of Yunnan Astronomical Observatories (YNAO). The spectrum is consistent with a type IIP supernova at a few days before the maximum light, showing a blue continuum and prominent P-Cygni features of Balmer lines. Cross-correlation with a library of supernova spectra using the "Supernova Identification" code (SNID; Blondin and Tonry 2007, Ap.J., 666, 1024) shows that it matches with SN 1999em at t = -3 days from the maximum light. After correcting for a redshift of 0.002 for its host galaxy M66, an expansion velocity of about 9000 km/s can be derived from the absorption minimum of Ha line.

Source: http://www.astronomerstelegram.org/?read=9093

In order to determine the difference between a type IIL and a type IIP SN one has to observe the light after it begins to decline. So how are they able to come to the conclusion that it is a type IIP if the SN has not even reached peak brightness yet?

 

[davenn]

Thanks for the image, but I am a bit confused. According to the Astronomer's Telegram they have already come to the conclusion that it is a type IIP SN even before it has reached peak brightness.

In order to determine the difference between a type IIL and a type IIP SN one has to observe the light after it begins to decline. So how are they able to come to the conclusion that it is a type IIP if the SN has not even reached peak brightness yet?

the answer is in the quote you posted.
I personally don't know the different in the spectrum between the two types, presumably they do and that is how they have drawn their conclusionDave