Introduction

The Sun is the closest star to Earth, and therefore provides the most fruitful opportunities for studying and understanding stellar mechanisms. Its proximity allows us to examine it at amazing resolution, in different wavelengths, and almost continuously. Beyond being a scientific curiosity, what happens on the Sun can affect our solar system, including Earth and, even sometimes, human activities through what is called space weather (learn more: NASA Space Weather and Space Weather ).

Observing the Sun in detail with many instruments has led to the discovery of many features and phenomena that scientists now investigate in detail. By understanding how the Sun works, we can by extension learn how other stars throughout the Universe work. While tremendous progress has been made, there are still many open questions in solar physics: How is the solar outer atmosphere (solar corona) heated to millions of degrees? How do energetic particles get accelerated and how do those particles propagate from the Sun through the solar system? How is the solar wind created and accelerated?

More information about the Sun can be found at NASA Sun and NASA Solar System.

Solar Jets

Studying solar jets, which are small and narrow ejections of solar material, may help us address some of the Sun's mysteries. For example, solar jets could be linked to energetic particles and perturbations in the solar wind. In this project, we focus on features that are found at various sizes and locations on the Sun, which can be observed clearly in extreme ultraviolet images.

Understanding solar jets will also help us understand data coming from NASA (National Aeronautics and Space Administration) and ESA (European Spatial Agency) flagship solar missions: the Parker Solar Probe and Solar Orbiter.

Parker Solar Probe: NASA Parker Solar Probe

Solar Orbiter: ESA and NASA

The need for a solar jet database

The goal of this Zooniverse project is to build a database of solar jets. Building this database will provide a jumping-off point for researchers to study the physics of solar ejections. The database will allow researchers to find interesting cases, compare data across other types of solar activity databases, and conduct broad statistical studies of jet properties.

We need your help

AIA, with its high resolution, high cadence, 7 wavelengths, and 10 years of continuous operation looking at the Sun has produced a LOT of data! In order to make use of this data, researchers need to know when and where on the Sun interesting things happened.

As a step towards identifying these notable events, NASA scientists developed algorithms that assess all the data and automatically detect features such as flares, filaments, and eruptions. These findings are stored in the Heliophysics Event Knowledge Database.

However, algorithms are not nearly enough. They are not always accurate, may miss events, and only give rough estimates of when and where they occurred.

A far more effective tool for finding interesting features on the Sun is the human eye! We need your help to locate solar jets. In this project, you'll dive into the SDO data to hunt down jets on the Sun!

The Data

The data used in this project is recorded in space by a satellite called SDO - the Solar Dynamic Observatory. SDO is a NASA mission that was launched in 2010, with several instruments onboard (more information on how SDO observes the Sun is available at NASA Goddard. One of the instruments, AIA (Atmosphere Imaging Assembly), is designed to produce high-resolution images of the Sun at different wavelengths in the extreme ultraviolet spectrum.

Learn more about the electromagnetic spectrum: NASA Spectrum and about ultraviolet and extreme ultraviolet emission: NASA UV.

In the extreme ultraviolet range, we can see the hot plasma of the Sun's atmosphere, produced in emission lines (at specific wavelengths) by positively charged particles (ions). Ions are formed in specific density and temperature conditions, therefore observing their emission at a particular wavelength tells us about the temperature of the ambient plasma in the solar atmosphere.

Solar jets, which are ejections of hot plasma in the solar atmosphere, can hence be seen in the AIA images by their thermal emission.

Every 12 seconds, AIA makes an image of the entire solar disk in several ultraviolet wavelengths. This sequence of images is quick enough to follow the evolution of rapid events that last for a few minutes, such as solar jets, making AIA an excellent instrument for this study.

In this project we use only one of the AIA wavelengths: the 30.4 nanometers (nm) filter. In this filter, jets are generally brighter than the average brightness of the Sun, which make them easier to spot in images or videos. However, many jets can be seen in more than one AIA filter, indicating that the jet plasma contains components at several different temperatures.

Everyone can access the data from SDO and other solar missions. Due to the volume of data, scientists at NASA and ESA have created software and a web interface called (J)Helioviewer, where images of the Sun can be displayed from different instruments at a chosen date. The web interface is at https://helioviewer.org/ . The data can also be downloaded for more in-depth analysis.