The Kepler Cluster Study: Stellar Rotation in NGC6811

TL;DR

This study measures rotation periods for 71 dwarf stars in NGC6811 using Kepler data, revealing a tight color-period relation that aids in age estimation and understanding stellar rotation evolution.

Contribution

First to combine Kepler photometry with ground-based spectroscopy for NGC6811, establishing a precise color-period relation for cluster dwarf stars.

Findings

Rotation periods form a tight sequence from 1 to 11 days.

Results extend the rotation-age relation to ~1 Gyr.

Supports using rotation as an age indicator for field stars.

Abstract

We present rotation periods for 71 single dwarf members of the open cluster NGC6811 determined using photometry from NASA's Kepler Mission. The results are the first from The Kepler Cluster Study which combine Kepler's photometry with ground-based spectroscopy for cluster membership and binarity. The rotation periods delineate a tight sequence in the NGC6811 color-period diagram from ~1 day at mid-F to ~11 days at early-K spectral type. This result extends to ~1 Gyr similar prior results in the ~600 Myr Hyades and Praesepe clusters, suggesting that rotation periods for cool dwarf stars delineate a well-defined surface in the 3-dimensional space of color (mass), rotation, and age. It implies that reliable ages can be derived for field dwarf stars with measured colors and rotation periods, and it promises to enable further understanding of various aspects of stellar rotation and activity for cool stars.