Related papers: The first rotation periods in Praesepe
Observational data on rotation of Ap stars suggest that the bulk of their rotation rates form a separate Maxwellian distribution with an average value 3-4 times lower than the normal star distribution. No evidences for a significant angular…
Rotation period clustering in prograde/retrograde rotators might indicate the preliminary indication of the Slivan state in the Koronis family as a result of the YORP effect. We follow the general scenario of dispersion in semimajor axis of…
Extended main-sequence turnoffs apparent in most young and intermediate-age clusters (younger than ~2 Gyr) are known features caused by fast rotating early-type (earlier than F-type) stars. Late-type stars are not fast rotators because…
It is not yet fully understood how planet formation affects the properties of host stars, in or out of a cluster; however, abundance trends can help us understand these processes. We present a detailed chemical abundance analysis of six…
Recent space-based missions have ushered in a new era of observational astronomy, where high-cadence photometric light curves for thousands to millions of stars in the solar neighborhood can be used to test and apply stellar age-dating…
Stellar models with masses ranging from 0.5 to $1.3~M_\odot$ were constructed in order to compare to young cluster observations of Li and of rotation velocities. The amount of Li depletion in cool stars is sensitive to the amount of…
We derive the effective temperatures and gravities of 461 OB stars in 19 young clusters by fitting the H-gamma profile in their spectra. We use synthetic model profiles for rotating stars to develop a method to estimate the polar gravity…
We examine the early angular momentum history of stars in young clusters via 197 photometric periods in fields flanking the Orion Nebula Cluster (ONC), 81 photometric periods in NGC 2264, and 202 measurements of v sin i in the ONC itself.…
We investigate the rotation velocity of the first stars by modelling the angular momentum transfer in the primordial accretion disc.Assessing the impact of magnetic braking, we consider the transition in angular momentum transport mode at…
We developed angular momentum evolution models for 0.5 and 0.8 $M_{\odot}$ stars. The parametric models include a new wind braking law based on recent numerical simulations of magnetised stellar winds, specific dynamo and mass-loss rate…
We have modeled in detail the evolution of rich open star clusters such as the Pleiades, Praesepe and Hyades, using simulations that include stellar dynamics as well as the effects of stellar evolution. The dynamics is modeled via direct…
We present rotation periods for thousands of active stars in the Kepler field derived from Q3 data. In most cases a second period close to the rotation period was detected, which we interpreted as surface differential rotation (DR). Active…
We report the spectroscopic confirmation of four further white dwarf members of Praesepe. This brings the total number of confirmed white dwarf members to eleven making this the second largest collection of these objects in an open cluster…
The nearby open cluster NGC 752 presents a rare opportunity to study stellar properties at ages >1 Gyr. However, constructing a membership catalog for it is challenging; most surveys have been limited to identifying its giants and dwarf…
Stellar activity and rotation frustrate the detection of exoplanets through the radial velocity technique. This effect is particularly of concern for M dwarfs, which can remain magnetically active for billions of years. We compile rotation…
We conduct a study of K to M type stars to investigate the activity and the rotation limit in the Hyades. We use a sample of 40 stars in this intermediate-age cluster (~625 Myr) to probe stellar rotation in the threshold region where…
Our ability to determine stellar ages from measurements of stellar rotation, hinges on how well we can measure the dependence of rotation on age for stars of different masses. Rotation periods for stars in open clusters are essential to…
Aims: We aim to measure the starspot rotation periods of active stars in the Kepler field as a function of spectral type and to extend reliable rotation measurements from F-, G-, and K-type to M-type stars. Methods: Using the Lomb-Scargle…
We study how chemical abundances of late B-, A- and early F-type stars evolve with time, and we search for correlations between the abundance of chemical elements and other stellar parameters, such as effective temperature and Vsini. We…
In recent years, ground- and space-based photometric surveys have characterized the rotational evolution of solar-like stars to an unprecedented level of detail. In this work we focus on the slow-rotator sequence, an emergent feature…