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Title: Informing the Cataclysmic Variable Sequence from Gaia Data: The Orbital-period–Color–Absolute-magnitude Relationship

The orbital-period (Porb) 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 (GBPGRP), absolute magnitude (MG), andPorb(between 70 minutes and 8 hr) revealed in Gaia DR2 and EDR3. We show thatPorbincreases 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 andMGfor a givenPorbspecifically for dwarf novae and intermediate polars above the period gap. These relations have the potential to inform a more complete picture of CV evolution.

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Publication Date:
Journal Name:
The Astrophysical Journal
Page Range or eLocation-ID:
Article No. 46
DOI PREFIX: 10.3847
Sponsoring Org:
National Science Foundation
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