5–7 Oct 2026
Konkoly Observatory, HUN-REN CSFK
Europe/Budapest timezone

Eppur binaria non é esclusa: Gaia astrometry does not disfavor a binary origin for Long Secondary Periods}

5 Oct 2026, 15:10
15m
Konkoly Observatory, HUN-REN CSFK

Konkoly Observatory, HUN-REN CSFK

10 minute talk

Speaker

Patryk Iwanek (Astronomical Observatory, University of Warsaw)

Description

Long Secondary Periods (LSPs) remain one of the major unresolved phenomena among red giant variables. An independent reassessment of the nearby LSP candidates analyzed by Shariat et al. (2026) is presented, based on long-term All Sky Automated Survey (ASAS) photometry and Gaia Focused Product Release (Gaia FPR) radial velocity data. Inspection of 221 candidates within 1.5 kpc from the Sun shows that only 103 objects, or about 47%, exhibit convincing LSP-like behavior, while the remaining stars are more naturally interpreted as semi-regular variables with irregular or multi-periodic pulsations. This substantial contamination limits the usefulness of the sample as a representative sequence-D population. In addition, gaiamock simulations show that even nearby LSP are not necessarily expected to display elevated Gaia RUWE values; therefore, the observed distance–RUWE relation does not provide evidence against the binary interpretation of LSPs.

Author

Patryk Iwanek (Astronomical Observatory, University of Warsaw)

Co-authors

Dr Piotr Kołaczek-Szymański (Astronomical Observatory, University of Warsaw) Prof. Dorota Skowron (Astronomical Observatory, University of Warsaw)

Presentation materials

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