New research shows that sunspots and other active regions can alter total solar emissions. The sunspots dim some emissions and brighten others. The timing of the changes also varies between different types of emissions. This knowledge will help astronomers characterize the conditions of stars, which has important implications for finding exoplanets around these stars.
An international research team led by Shin Toriumi of the Japan Aerospace Exploration Agency added up the different types of emissions observed from a satellite fleet, including “HinodeAnd the “Solar Dynamics Observatory” to see what the sun would look like if it were viewed from a distance as a single point of light like other stars.
The team looked at how features like sunspots change the bigger picture. They found that a sunspot located in the center of the side of the sun facing us obscures the total amount of visible light. If, on the other hand, the sunspots are located near the edge of the sun, all visible light becomes brighter, since at this viewing angle light structures, so-called faculae, which surround the sunspots, are more visible than the dark centers.
In addition, X-rays generated in the corona above the sun’s surface become brighter when a sunspot is visible. The coronal loops that span the sunspot are heated magnetically so that this brightening occurs before the sunspot itself rotates into view and persists even when the sunspot is out of sight.
Because the changes in total solar emissions and their timings provide information about the location and structure of features on the solar surface, astronomers hope to infer the surface features of other stars such as star spots and magnetic fields. This will help astronomers get through the shadow of a Exoplanet. With a better knowledge of the effects of star spots, we can more accurately estimate the parameters such as radii and orbits of exoplanets.
An in-depth study of the sun will provide a better understanding of the detailed mechanisms of atmospheric warming and flare eruptions. Toriumi comments: “To this end, the next generation solar observation satellite Solar-C (EUVST), developed by Japan in close collaboration with US and European partners, aims to observe the sun in emissions that examine the chromosphere and the transition region Corona as a single system. ”
For more information on this research, see A New Look at Sunspots Helps NASA Understand Life Around Other Stars.
Reference: “Observations of the Spectral Irradiance of the Sun as a Star in Active Regions” by Shin Toriumi, Vladimir S. Airapetian, Hugh S. Hudson, Carolus J. Schrijver, Mark CM Cheung and Marc L. DeRosa, October 8, 2020, Astrophysical Journal.
DOI: 10.3847 / 1538-4357 / abadf9