Variables in DP0

I am interested to find whether there are Mira variable stars within the DP0.

I know that RR Lyrae and Cepheids are mentioned, but Miras are not. I know there was already a discussion (Periods of variable stars) on the availability of the periods used to generate the variable stars within the DP0, but the answer is not encouraging.

Therefore, my questions are

  1. Are there Miras in the DP0.1? I do not need to know their periods, coordinates or any other property, but I need to know whether they were included or not.
  2. Would the DP0.2 include some more information? i.e., a flag for the type of variability?

Thank you

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Hi @VFBraga , thanks for this question.

I don’t yet have an answer for you, but for now I can say that Section 5.3. “The Local DC2 Universe: The Milky Way” of the paper “The LSST DESC DC2 Simulated Sky Survey” (The DESC et al. 2020) does mention several types of variable stars such as RR Lyrae and Cepheids were simulated, but does not explicitly say whether Mira variables were included.

At the moment, more detailed truth data aside from what the Data Preview 0.1 “truth_match” table offers is not currently available. However, DESC is working on generating additional truth tables for a future public release, and these might provide what you need.

The DP0.2 catalogs will include lightcurves for variable objects, generated from difference-image sources, and so DP0 delegates should be able to identify Mira-like variables.

After asking around, it sounds like the answer is “no Mira variables in DC2”.

And that there were 3 models for stellar variability:

  • MLT (cool dwarf stellar flares; ~50% of stars)
  • kplr (derived from Kepler light curves; ~40%)
  • applyRRly (RR lyrae; 1196 stars, 0.006%)

with no variability applied for ~3% of stars.

For posterity, the types and fractions above come from this post: Summary Truth catalogs for stars · Issue #386 · LSSTDESC/DC2-production · GitHub

However, note that not all cases of simulated variability are detectable. As described in Section 5.3 of the DESC’s DC2 paper (linked in my last post): “approximately 10% of the stellar sources expected to be variable at a level detectable by LSST” (i.e., at the mmag level).

Dear @MelissaGraham

Thank you for your answer. I could not find that table before. This is clear now.

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