The luminous bore in eta Carinae around the 2025.7 periastron

• Grant number: 25/08626-3
• Support Opportunities: Scholarships in Brazil - Scientific Initiation
• Start date: August 01, 2025
• End date: July 31, 2026
• Field of knowledge: Physical Sciences and Mathematics - Astronomy - Stellar Astrophysics
• Principal Investigator: Augusto Damineli Neto
• Grantee: Rodrigo Braz Sartori Capobiango
• Host Institution: Instituto de Astronomia, Geofísica e Ciências Atmosféricas (IAG). Universidade de São Paulo (USP). São Paulo , SP, Brazil
• Associated research grant: 24/16086-6 - THE "BORE HOLE" IN ETA CARINAE AROUND THE 2025.7 PERIASTRON, AP.R

Abstract

We plan to perform photometric and spectroscopic monitoring of Eta Carinae in 2025 to characterize the "luminous bore hole" phenomenon, which is expected to reach its highest amplitude in the historical series in August 2025. This is a new phenomenon in Astrophysics that has not yet been adequately characterized either observationally or theoretically. Photometry will be performed with UBV filters to measure the photometric peak in the V band and the Balmer Jump (U-B color index). Spectroscopic observations will be focused on the HeII4686A line that has been monitored since 2003. The data will allow us to improve the measurements of the orbital period and the recent discovery that the luminous peaks are advancing by 1 day per orbit. If confirmed, this phenomenon characterizes an instability in the orbit, which could lead to a "merge" between the two stars on a time scale of a few centuries. This phenomenon is of special interest for the field of gravitational wave emission. (AU)