Marc H. Pinsonneault

TL;DR: In this article, the authors measured the masses of 40 stars on the RGB and 19 in the RC of the old metal-rich cluster NGC6791 and NGC6819 and found that the difference between the average mass of RGB and RC stars is small, but significant.

TL;DR: In this article, a long-baseline interferometry campaign using the PAVO beam combiner at the CHARA Array was used to measure the angular sizes of five main-sequence stars, one subgiant and four red giant stars for which solar-like oscillations have been detected by either Kepler or CoRoT.

TL;DR: In this paper, the authors outline how to make an estimate of the detectability of solar-like oscillations in any given Kepler target, using rough estimates of the temperature and radius, and the Kepler apparent magnitude.

TL;DR: In this paper, a subset of red giants, observed towards the North Galactic Gap, during the mission's first full science campaign, was used for detecting oscillations in red giants that span a range in apparent magnitude and evolutionary state.

Abstract: We present an analysis of K2 light curves (LCs) for candidate members of the young Upper Sco (USco) association $\sim$8 Myr) and the neighboring Rho Oph embedded cluster ($\sim$1 Myr). We establish $\sim$1300 stars as probable members, $\sim$80\% of which are periodic. The phased LCs have a variety of shapes which can be attributed to physical causes ranging from stellar pulsation and stellar rotation to disk-related phenomena. We identify and discuss a number of observed behaviors. The periods are $\sim$0.2-30 days with a peak near 2 days and the rapid period end nearing break-up velocity. M stars in the young USco region rotate systematically faster than GK stars, a pattern also present in K2 data for the older Pleiades and Praesepe systems. At higher masses (types FGK), the well-defined period-color relationship for slowly rotating stars seen in the Pleiades and Praesepe is not yet present in USco. Circumstellar disks are present predominantly among the more slowly rotating Ms in USco, with few disks in the sub-day rotators. However, M dwarfs with disks rotate faster on average than FGK systems with disks. For four of these disked Ms, we provide direct evidence for disk-locking based on the K2 LC morphologies. Our preliminary analysis shows a relatively mass-independent spin-up by a factor of $\sim$3.5 between USco and the Pleiades, then mass-dependent spin-down between Pleiades and Praesepe.