Magnetic Braking Formulation for Sun-Like Stars: Dependence on Dipole Field Strength and Rotation Rate

We use two-dimensional axisymmetric magnetohydrodynamic simulations to compute steady-state solutions for solar-like stellar winds from rotating stars with dipolar magnetic fields. Our parameter study includes 50 simulations covering a wide range of relative magnetic field strengths and rotation rates, extending from the slow- and approaching the fast-magnetic-rotator regimes. Using the simulations to compute the angular momentum loss, we derive a semi-analytic formulation for the external torque on the star that fits all of the simulations to a precision of a few percents. This formula provides a simple method for computing the magnetic braking of sun-like stars due to magnetized stellar winds, which properly includes the dependence on the strength of the magnetic field, mass loss rate, stellar radius, suface gravity, and spin rate and which is valid for both slow and fast rotators.Comment: Accepted for publication in ApJ Letters, 6 pages, 4 figure

Lone parents and employment: an exploration of findings from the Families and Children Study 2006-08 (Working paper no 93)

"In order to better understand some of the key issues for all mothers in combining paid work and parenting DWP and the National Centre for Social Research (NatCen) developed in 2006 a series of questions for use on the Families and Children Study (FACS)... The findings presented in this working paper refer to the FACS data for lone mothers only and it is the first time that the Choices and Constraints set has been analysed longitudinally. One reason for conducting this analysis was to contribute to the wider evidence on lone mothers’ decisions regarding employment. However, given that this question set will be used in future research projects, including the LPO evaluation, the analysis was also commissioned to inform how longitudinal data emerging from LPO might best be explored. For this reason this working paper also contains technical detail describing the analysis process itself." - Page 1

Lone parents and employment : an exploration of findings from the Families and children study 2006-08

"This working paper presents findings from longitudinal analysis of c.800 lone mothers who responded to the Families and Children Study (FACS) between 2006 and 2008. The analysis utilises data from the Choices and Constraints question set which was designed to capture the complexities of decision-making for parents around work and caring in order to better understand their decisions, motivations and barriers with regard to employment. Structural Equation Modelling (SEM) was undertaken to explore the relationship between some of the background characteristics of lone mothers who took part in FACS and how these interact with their attitudes, perceptions and intentions, which in turn impact on their employment outcomes. This analysis includes substantial technical detail as it was undertaken in order to explore the value of applying SEM to the Choices and Constraints question set. It was commissioned as part of the Lone Parent Obligations evaluation programme." -- Back cover