VSX: Is there an "em" spectral type?

Affiliation
American Association of Variable Star Observers (AAVSO)
Fri, 12/22/2023 - 22:33

Hello,

When checking in VSX some information about the star CW Cru, one of the targets I monitored recently, I noticed that it is classified as belonging to the "em" spectral class. Is there an "em" spectral class?

Simbad reports it in the B0IIIe C spectral class (Aidelman et al., 2018, Astronomy and Astrophysics, volume 610A, 30-30).

If anyone could comment, please.

Thanks.

Ari

Affiliation
Variable Stars South (VSS)
Symbols in the additional nomenclature

I think the following applies: e means emission lines present; m means enhanced metal features.

Roy

Affiliation
American Association of Variable Star Observers (AAVSO)
em

Ari, you have posted the same question both to the Spectroscopy and the VSX forums. You are getting different replies in each forum. I recommend posting to one forum only to avoid this.

Let's continue the thread in:

https://www.aavso.org/there-em-spectral-type

Roy, em just means "emission".
When no spectral class is given and only emission lines are reported, you can just find "em".

Cheers,
Sebastian