Unusual stunted outbursts in the nova-like variable HS 0229+8016

TL;DR

This study analyzes nearly 13 years of light curve data of HS 0229+8016, revealing unusual stunted outbursts and brightness variations that challenge previous classifications, highlighting the need for ongoing observation.

Contribution

It provides the first detailed long-term light curve analysis of HS 0229+8016, identifying unique outburst patterns and questioning its classification as a Z Cam dwarf nova.

Findings

Detected cyclic 0.6 mag variations lasting about 9.5 days.

Observed intervals of up to 166 days with reduced or halted outbursts.

No evidence of typical dwarf nova outbursts or standstills.

Abstract

We present the light curve of HS 0229+8016 between 2006 and 2019 which shows that the star varies between mag 13.4 and 15.1. There were episodes lasting up to hundreds of days during which distinctive 0.6 mag cyclic variations were apparent, each lasting ca. 9.5 days. Observationally, these are very similar to the stunted outbursts seen from time to time in several nova-like cataclysmic variables, such as UU Aqr. There are two intervals of up to 166 days when these stunted outbursts appeared to reduce or even stop. These coincide with the system being up to ca. 0.7 mag fainter than usual. Previous workers have suggested that HS 0229+8016 might be a member of the Z Cam family of dwarf novae, but we can find no evidence of the characteristic dwarf nova outbursts and standstills at an intermediate brightness. Surveillance of HS 0229+8016 should be continued to understand more about the long-term behaviour of this system.