2002/06/17 by B. Stelzer, Stelzer, B., R. Neuhäeuser +2
Physics and Astronomy · #Astro and Planetary Science #Astrophysics (astro-ph) #FOS: Physical sciences #Solar and Space Plasma Dynamics #Stellar, planetary, and galactic studies #astro-ph
paper · pdf · doi:10.48550/arxiv.astro-ph/0206284
4 pages, to appear in proceedings of the IAU Symposium 211 on "Brown Dwarfs", ASP Conference Series
arxiv created 2002/06/17 · openalex publication_date 2002/06/17 · arxiv updated 2009/12/01 · openalex created_date 2025/10/10 · openalex updated_date 2026/07/28
According to the paradigm of solar-type dynamo action brown dwarfs should not exhibit magnetic activity as they are fully convective. Indeed, Halpha observations of ultracool field dwarfs indicate a decline of activity setting in near the substellar limit. X-ray emission traditionally serves as another means to examine magnetic activity on stars. The substellar regime can now be accessed with the new generation of X-ray instruments onboard XMM-Newton and Chandra. We report on two recent XMM-Newton observations of brown dwarfs in the Pleiades cluster and in the field aiming to constrain the age and effective temperature dependence of X-ray emission from substellar objects.