Modify Concept: Beta Cepheid variable stars

astrothesaurus / UAT

The Unified Astronomy Thesaurus is an open, interoperable and community-supported thesaurus of astronomical and astrophysical concepts and their relationships.

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Modify Concept: Beta Cepheid variable stars #283

Closed rpoleski closed 4 years ago

rpoleski commented 4 years ago

Name the concept in question "Beta Cepheid variable stars" http://astrothesaurus.org/uat/148

Describe the change The concept should not be a child of "Cepheid variable stars." This is just a coincidence that prototypes of Delta Cep and Beta Cep stars are in the same constellation. See first paragraph of https://en.wikipedia.org/wiki/Beta_Cephei_variable

Please include any additional comments/feedback See also frequently-reproduced Fig. 1 from Eyer & Mowlavi 2008 (BCEP and CEP in green part).

katieefrey commented 4 years ago

Interesting, thanks, I did not realize this nuance before and I will look into it more.

From https://en.wikipedia.org/wiki/Cepheid_variable, other potential things to note and investigate:

"Classical Cepheids (also known as Population I Cepheids, type I Cepheids, or Delta Cepheid variables)"
"Type II Cepheids (also termed Population II Cepheids)... are divided into several subgroups by period. Stars with periods between 1 and 4 days are of the BL Her subclass, 10–20 days belong to the W Virginis subclass, and stars with periods greater than 20 days belong to the RV Tauri subclass."

also from that wiki entry, these two already exist as UAT concepts:

Anomalous Cepheids
Double-mode Cepheids

rpoleski commented 4 years ago

Yes, type II Cepheids are divided into 3 subclasses: BL Her, W Vir, and RV Tau. The period boundaries are 4-5 days and 20 days - see this website, which was prepared by Igor Soszyński. There are references to his original papers there and on wikipedia page. He investigated this classification in detail.

katieefrey commented 4 years ago

We actually have concepts for all three of the subclasses, but not one for the type II cepheids, which is interesting... I want to look into that further.

rpoleski commented 4 years ago

I think adding "Type II Cepheids" with 3 child concepts is a good idea. The fact that BL Her, W Vir, and RV Tau are connected is well visible in the first plot on the webpage I've linked (it's period-luminosity relation, which is fundamental in astronomy). If you go here you will see that Anomalous Cepheids are also a separate class.

katieefrey commented 4 years ago

accepted and implemented, will be in the next release.

Concept renamed to "Beta Cephei variable stars" (instead of cepheid). No longer a child of "Cepheid variable stars."

"Type II Cepheid variable stars" added, and BL Her, W Vir, and RV Tau moved under it.