Element spots in HgMn stars

: Korhonen H

: Mathys G, Griffin ER, Kochukhov O, Monier R, Wahlgren GM

: International Conference on Putting A Stars into Context - Evolution, Environment, and Related Stars

: 2014

: Putting a stars into context: evolution, environment, and related stars

: PUTTING A STARS INTO CONTEXT: EVOLUTION, ENVIRONMENT, AND RELATED STARS

: 173

: 181

: 9

: 978-5-00086-273-5

A fraction of late B-type stars, the so-called HgMn stars, exhibit enhanced absorption lines of certain chemical elements, notably Hg and Mn, combined with an underabundance of He. For about a decade it has been known that the elements with anomalously high abundances in HgMn stars are distributed inhomogeneously over the stellar surface. Observation of the temporal evolution of those spots has been reported in a few HgMn stars, first of a secular evolution of the mercury spots in a And, and more recently of a fast evolution of yttrium and strontium spots in HD 11753. The fast evolution of spots in HD 11753 is combined with a slower change in the overall abundance of the elements affected. In this paper I review what is known about these "elemental spots" in HgMn stars and their secular and fast temporal evolution.