Informing the Cataclysmic Variable Sequence from Gaia Data: The Orbital-period-Color-Absolute-magnitude Relationship
Abstract
The orbital-period (P orb) gap in the population of cataclysmic variables (CVs) informs the theoretical narrative of CV evolution, yet a complete understanding of the driving angular momentum loss mechanisms above and below this gap remains elusive. Here we identify, for standard CVs, a new, apparently monotonic relationship between quiescent color (G BP-G RP), absolute magnitude (M G ), and P orb (between 70 minutes and 8 hr) revealed in Gaia DR2 and EDR3. We show that P orb increases in the color-absolute-magnitude diagram roughly orthogonally to the white dwarf and main sequences. We find the orbital-period-color-absolute-magnitude relationship to be stable across different CV subtypes: dwarf novae, intermediate polars, polars, and novalike systems. We place our findings in context with the known semiempirical donor sequence for CVs and find a dependence between color and M G for a given P orb specifically for dwarf novae and intermediate polars above the period gap. These relations have the potential to inform a more complete picture of CV evolution.
- Publication:
-
The Astrophysical Journal
- Pub Date:
- October 2022
- DOI:
- 10.3847/1538-4357/ac87ab
- Bibcode:
- 2022ApJ...938...46A
- Keywords:
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- Cataclysmic variable stars;
- Variable stars;
- Surveys;
- Hertzsprung Russell diagram;
- Close binary stars;
- 203;
- 1761;
- 1671;
- 725;
- 254