Comparative Analysis of a Transition Region Bright Point with a Blinker and Coronal Bright Point Using Multiple EIS Emission Lines

TL;DR

This study spectroscopically compares transition region bright points, blinkers, and coronal bright points using EUV emission lines, revealing differences and similarities in their physical properties and magnetic configurations to aid automated classification.

Contribution

First spectroscopic analysis of TRBPs, comparing their properties with blinkers and CBPs to identify distinguishing features and improve classification methods.

Findings

Doppler velocities < 25 km/s for TRBP and blinker, < 20 km/s for CBP

Evidence of single and double isothermal components in TRBP and CBP

Similar magnetic and EUV flux evolution suggest multi-scaled self similarity

Abstract

Since their discovery twenty year ago, transition region bright points (TRBPs) have never been observed spectroscopically. Bright point properties have not been compared with similar transition region and coronal structures. In this work we have investigated three transient quiet Sun brightenings including a TRBP, a coronal BP (CBP) and a blinker. We use time-series observations of the extreme ultraviolet emission lines of a wide range of temperature T (log T = 5.3 - 6.4) from the EUV imaging spectrometer (EIS) onboard the Hinode satellite. We present the EIS temperature maps and Doppler maps, which are compared with magnetograms from the Michelson Doppler Imager (MDI) onboard the SOHO satellite. Doppler velocities of the TR BP and blinker are <,25 km s$^{-1}$, which is typical of transient TR phenomena. The Dopper velocities of the CBP were found to be < 20 km s^{-1} with exception of those measured at log T = 6.2 where a distinct bi-directional jet is observed. From an EM loci analysis we find evidence of single and double isothermal components in the TRBP and CBP, respectively. TRBP and CBP loci curves are characterized by broad distributions suggesting the existence of unresolved structure. By comparing and contrasting the physical characteristics of the events we find the BP phenomena are an indication of multi-scaled self similarity, given similarities in both their underlying magnetic field configuration and evolution in relation to EUV flux changes. In contrast, the blinker phenomena and the TRBP are sufficiently dissimilar in their observed properties as to constitute different event classes. Our work indicates that the measurement of similar characteristics across multiple event types holds class-predictive power, and is a significant step towards automated solar atmospheric multi-class classification of unresolved transient EUV sources.