Magnetically Active Stars Subgroup

Topic Area

The Magnetically Active Stars subgroup studies the photometric variability from stars induced by the presence of surface magnetism. This includes Sun-like stars whose brightness is modulated by the passage of dark active regions (starspots) and bright faculae, as well as RS CVn and T Tauri variables. The overarching goal is to understand the dynamo processes responsible for generating magnetism in these objects.


Subgroup Contact:
Ricky Egeland
High Altitude Observatory

  • Marcel Agueros
  • Patrick Hartigan
  • Suzanne Hawley
  • Chris Johns-Krull
  • Stella Kafka
  • Adam Kowalski
  • Nicole Silvestri
  • Keivan Stassun
  • Lucianne Walkowicz

LSST Science

LSST data on magnetically variable stars will help to address the following science quesitons:

What is the dependence between photometric variability and fundemental properties such as mass and rotation?

What fraction of Sun-like main-sequence stars are in a quiescenet "Maunder Minimum" state?

What fraction of Solar Analogues have a Sun-like cycle?

Do identical stars have identical magnetic variability?


The roadmap from the Magnetically Active Stars subgroup is presently under discussion. The roadmap will outline the necessary steps to prepare for LSST data in order to address the science questions above.


  • Radick et al. 2018, ApJ "Patterns of Variation for the Sun and Sun-like Stars"
    Describes results from 25 years of precision photometry for a sample of 72 Sun-like stars.
  • Hawley et al. 2016, arxiv "Maximizing Science in the Era of LSST, Stars Study Group Report: Rotation and Magnetic Activity in the Galactic Field Population and in Open Star Clusters"
    This is the stars chapter of the Kavli workshop report, which resulted from the community-based study of needed US OIR capabilities in the LSST era.
  • Hawley et. al, arxiv "A Mini-Survey of the Old Open Cluster M67", Section 10.4 of "Science-Driven Optimization of the LSST Observing Strategy" by the LSST Collaboration, August 2017.
    Motivates an LSST survey of M67, an open cluster whose relative compactness, age, and location above the galactic plane combine to make it the ideal cluster for a closer look.
  • Hilton et al. 2009, arxiv "Magnetic Activity: Flares and Stellar Cycles" Section 8.9 of "LSST Science Book" Version 2.0, November 2009.
    Flaring and activity in M-dwarfs (Section 8.9.1); Potential for activity cycles (Section 8.9.2).