Photometric Observations of the Eta Carinae 2009.0 Spectroscopic Event

TL;DR

This study presents photometric observations of Eta Carinae during its 2009 spectroscopic event, confirming periodic minima and refining the event's period to approximately 2022.6 days, contributing to understanding its binary nature.

Contribution

The paper provides detailed photometric data during the 2009 event and refines the periodicity estimate, aiding in the study of Eta Carinae's binary system and its variability.

Findings

Confirmed the periodicity of the spectroscopic event

Refined the event period to 2022.6 days

Updated brightness measurements of comparison stars

Abstract

We have observed Eta Carinae over 34 nights between 4th January 2009 and 27th March 2009 covering the estimated timeframe for a predicted spectroscopic event related to a suspected binary system concealed within the homunculus nebula. A photometric minimum feature was confirmed to be periodic and comparison to a previous event indicated that the period to within our error at 2022.6 +/-1.0 d. Using the E-region standard star system, the apparent V magnitudes determined for the local comparison stars were HD303308 8.14+/-0.02, HD 93205 7.77 +/-0.03 and HD93162 8.22 +/-0.05. The latter star was found to be dimmer than previously reported.