Quasi-Periodic Oscillation of a Coronal Bright Point

TL;DR

This study investigates the quasi-periodic brightenings of a coronal bright point in the solar corona, linking these oscillations to magnetic flux changes and small-scale reconnection events observed with high-resolution instruments.

Contribution

It provides detailed analysis of the dynamics and oscillations of a coronal bright point using multi-instrument data, highlighting the role of reconnection in quasi-periodic brightenings.

Findings

Periodic brightenings linked with magnetic flux changes.

Enhanced line profiles indicating reconnection outflows.

Reconnection events likely cause the observed oscillations.

Abstract

Coronal bright points (BPs) are small-scale luminous features seen in the solar corona. Quasi-periodic brightenings are frequently observed in the BPs and are generally linked with underneath magnetic flux changes. We study the dynamics of a BP seen in the coronal hole using the Atmospheric Imaging Assembly (AIA) images, the Helioseismic and Magnetic Imager (HMI) magnetogram on board the Solar Dynamics Observatory (SDO) and spectroscopic data from the newly launched Interface Region Imaging Spectrograph (IRIS). The detailed analysis shows that the BP evolves throughout our observing period along with changes in underlying photospheric magnetic flux and shows periodic brightenings in different EUV and FUV images. With highest possible spectral and spatial resolution of IRIS, we attempted to identify the sources of these oscillations. IRIS sit and stare observation provided a unique opportunity to study the time evolution of one foot point of the BP as the slit position crossed it. We noticed enhanced line profile asymmetry, enhanced line width, intensity enhancements and large deviation from the average Doppler shift in the line profiles at specific instances which indicate the presence of sudden flows along the line of sight direction. We propose that transition region explosive events (EEs) originating from small scale reconnections and the reconnection outflows are affecting the line profiles. The correlation between all these parameters is consistent with the repetitive reconnection scenario and could explain the quasi-periodic nature of the brightening.