ERC Starting Grant for Alexander Shapiro

MPS scientist investigates brightness fluctuations of the Sun and stars.

March 13, 2017

The Sun is an unusual star - even when compared to those which resemble it in size, luminosity, and magnetic properties. Investigations of the past years show that the Sun’s brightness variations following an eleven year cycle are markedly weaker than those of most comparable stars. In the next five years, Dr. Alexander Shapiro from the Max Planck Institute for Solar System Research (MPS) wants to investigate the reasons for this difference. With his new research group "Connecting Solar and stellar Variables (SOLVe)", he is looking for the link between the Sun and stars. Why do these bodies behave so similarly and yet so differently? And can findings from solar research be transferred to distant stars? The European Research Council (ERC) is now supporting this project with a Starting Grant.

Traditionally, solar and stellar research are rather separate disciplines. One of the reasons is the completely different accessibility of their research objects: While numerous satellites orbiting Earth and space probes observe the Sun from close up and supply a wealth of different measurement data, information about other stars has to be excerpted from light that has traveled many trillion kilometers to reach Earth.

In recent years, however, the situation has changed, says Dr. Alexander Shapiro. One of the driving forces behind this development was the discovery of stellar brightness fluctuations following their activity cycles – and thus very akin to the Sun’s eleven-year cycle. These stellar variations have proven to be much stronger than those of the Sun. Possibly, this also holds true for variations on shorter time scales. Thanks to the CoRoT and Kepler space telescopes provided by the French and European space agencies, exact measurements from a large number of stars are now available with an unprecedented level of accuracy. The planned missions TESS and PLATO will further improve the data situation.

"At the same time, our understanding of the Sun has increased significantly," Shapiro adds. As a member of the working group "Solar Variability and Climate" at the MPS, Shapiro was able to contribute to explaining which magnetic processes on the Sun are responsible for solar brightness fluctuations. 

With the help of the ERC Starting Grant, Shapiro now wants to take the next logical step and apply the models that proved their worth in the study of the Sun to distant stars. The researcher hopes to clarify why the perennial brightness fluctuations of many stars are much stronger than those of the Sun.

In addition, he wants to investigate the changes in brightness occurring on much shorter time scales. "Such measurements are used to track down exoplanets," Shapiro says. When during its orbit, an exoplanet crosses the line of sight between its star and Earth, this can be detected as a decrease in brightness. Shapiro's approach aims to distinguish better, whether such fluctuations are due to an exoplanet transit or to inner properties of the star.

With the Starting Grants the European Research Council supports young scientists at the beginning of their scientific careers. The grants allow them to establish new research groups and to pursue their own, ground-breaking projects.

Dr. Alexander Shapiro studied mathematics and astronomy at the University of St. Petersburg (Russia). In 2009, he was awarded his doctorate by the Eidgenössische Technische Hochschule (ETH) in Zürich (Switzerland). He continued his research first at the Physical Meteorological Observatory / World Radiation Center in Davos, then as Marie Curie Fellow at the MPS, where he worked in the research group "Solar Variability and Climate".

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