The Monitor Project: stellar rotation at 13 Myr

Moraux, E.; Artemenko, S. A.; Bouvier, J.; Irwin, Jonathan; Ibrahimov, M.; Magakian, T. Yu.; Grankin, K. N.; Nikogossian, E. H.; Cardoso, C.; Hodgkin, S. T.; Aigrain, S.; Movsessian, T. A.

doi:10.1051/0004-6361/201321508

Cited by 67 publications

(128 citation statements)

References 58 publications

Supporting

Mentioning

116

Contrasting

Order By: Relevance

“…Figure 8 shows the variation of the coupling timescales upon angular velocity as derived from our parametric models. A power-law fit yields τ c−e ∝ 1/Ω [0.4−0.6] conv , while a previous study by Moraux et al (2013) of PMS and ZAMS clusters suggested τ c−e ∝ 1/Ω. While these parametric slopes are at variance with the analytical predictions, they nevertheless agree with the expected trend for a shorter coupling timescale in faster rotators.…”

Section: Core-envelope Decoupling and The Timescale For Angular Momensupporting

confidence: 57%

“…Most stellar quantities increase for higher mass stars (i.e. the stellar radius and moment of inertia, the moment of inertia of the radiative core, as well as its radius and 1 We thus rejected M 50-5-1624, -3-1468, -3-464, -7-7623, -3-5840, -7-5624, -5-2673, -3-7334, -3-2531, -6-1574, -4-2077, -4-4939, and -8-6076 from M 50 ), N2362-2-6989, and N2362-5-4947 from NGC 2362, #11041 (number from Hillenbrand 1997) from ONC, and #494 (number from Moraux et al 2013) from h Per, and #3245 (number from Littlefair et al 2010) from CepOB3b. 2 We thus rejected 1SWASP J083722.23+201037.0 (KW 30) and 1SWASP J084005.72+190130.7 (KW 256) in Praesepe (Delorme et al 2011).…”

Section: Structural Stellar Evolutionmentioning

confidence: 99%

See 1 more Smart Citation

Improved angular momentum evolution model for solar-like stars

Gallet

Bouvier

2015

A&A

Self Cite

229

290

View full text Add to dashboard Cite

Context. Understanding the physical processes that dictate the angular momentum evolution of solar-type stars from birth to maturity remains a challenge for stellar physics. Aims. We aim to account for the observed rotational evolution of low-mass stars over the age range from 1 Myr to 10 Gyr. Methods. We developed angular momentum evolution models for 0.5 and 0.8 M 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 prescriptions, as well as core-envelope decoupling. We compare model predictions to the distributions of rotational periods measured for low-mass stars belonging to star-forming regions and young open clusters. Furthermore, we explore the mass dependence of model parameters by comparing these new models to the solar-mass models we developed earlier.Results. Rotational evolution models are computed for slow, median, and fast rotators at each stellar mass. The models reproduce reasonably well the rotational behaviour of low-mass stars between 1 Myr and 8−10 Gyr, including pre-main sequence to zero-age main sequence spin up, prompt zero-age main sequence spin down, and early-main sequence convergence of the surface rotation rates. Fast rotators are found to have systematically shorter disk lifetimes than moderate and slow rotators, thus enabling dramatic pre-main sequence spin up. They also have shorter core-envelope coupling timescales, i.e., more uniform internal rotation. As for the mass dependence, lower mass stars require significantly longer core-envelope coupling timescales than solar-type stars, which results in strong differential rotation developing in the stellar interior on the early main sequence. Lower mass stars also require a weaker braking torque to account for their longer spin-down timescale on the early main sequence, while they ultimately converge towards lower rotational velocities than solar-type stars in the longer term because of their reduced moment of inertia. We also find evidence that the mass dependence of the wind braking efficiency may be related to a change in the magnetic topology in lower mass stars. Conclusions. We have included in parametric models the main physical processes that dictate the angular momentum evolution of low-mass stars. The models suggest that these processes are quite sensitive to both mass and instantaneous rotation rate. We have worked out and reported here the main trends of these mass and rotation dependencies, whose origin still have to be addressed through a detailed modelling of magnetised stellar winds, internal angular momentum transport processes, and protoplanetary disk dissipation mechanisms.

show abstract

Section: Core-envelope Decoupling and The Timescale For Angular Momensupporting

confidence: 57%

Section: Structural Stellar Evolutionmentioning

confidence: 99%

Improved angular momentum evolution model for solar-like stars

Gallet

Bouvier

2015

A&A

Self Cite

229

290

View full text Add to dashboard Cite

show abstract

“…Our results agree reasonably well with these observations. However, at 12.1 Myr, our simulation does not reproduce the bimodal rotational distribution of h Per cluster members, which exhibit one peak at ≤1 day and another at 3−7 days (Moraux et al 2013). Instead, the period distribution of diskless stars in our simulation moves to shorter periods as a whole by an age of 12.1 Myr with a single peak at P peak ∼ 2 days.…”

Section: Model M1mentioning

confidence: 65%

“…Squares represent Class II stars, crosses Class III stars. At 13 Myr, the specific angular momenta of h Per members from Moraux et al (2013) are plotted as gray diamonds.…”

Section: Period -Mass Relationshipmentioning

confidence: 99%

Investigating the rotational evolution of young, low-mass stars using Monte Carlo simulations

Vasconcelos

Bouvier

2015

A&A

Self Cite

View full text Add to dashboard Cite

Context. Young stars rotate well below break-up velocity, which is thought to result from the magnetic coupling with their accretion disk. Aims. We investigate the rotational evolution of young stars under the disk-locking hypothesis through Monte Carlo simulations. Methods. Our simulations included 280 000 stars, each of which was initially assigned a mass, a rotational period, and a mass accretion rate. The mass accretion rate depends on both mass and time, following power-law indices of 1.4 and −1.5, respectively. A mass-dependent accretion threshold was defined below which a star was considered as diskless, which resulted in a distribution of disk lifetimes that matches observations. Stars were evolved at constant angular spin rate while accreting and at constant angular momentum when they became diskless. Results. Starting with a bimodal distribution of periods for disk and diskless stars, we recovered the bimodal period distribution seen in several young clusters. The short-period peak mostly consists of diskless stars, and the long-period peak is mainly populated by accreting stars. Both distributions, however, present a long tail toward long periods, and a population of slowly rotating diskless stars is observed at all ages. We reproduced the observed correlations between disk fraction and spin rate, as well as between IR excess and rotational period. The period-mass relation we derived from the simulations only shows the same global trend as observed in young clusters when we released the disk-locking assumption for the lowest mass stars. Finally, we find that the time evolution of median specific angular momentum follows a power-law index of −0.65 for accreting stars, as expected from disk locking, and of −0.53 for diskless stars, a shallower slope that results from a wide distribution of disk lifetimes. At the end of the accretion phase, our simulations reproduce the angular momentum distribution of the low-mass members of the 13 Myr h Per cluster. Conclusions. Using observationally documented distributions of disk lifetimes, mass accretion rates, and initial rotation periods, and evolving an initial population from 1 to 12 Myr, we reproduced the main characteristics of pre-main sequence angular momentum evolution, which supports the disk-locking hypothesis.

show abstract

“…In particular, the advent of large surveys designed to search for extrasolar planets has yielded very large data sets of stellar rotation periods as a natural byproduct for both field stars (Hartman et al 2011) and open clusters stars. Examples of the latter include the extensive MONITOR program (Aigrain et al 2007) (see Moraux et al 2013, for the most recent results), the SuperWASP data for the Hyades and Praesepe (Delorme et al 2011) and the large (Hartman et al 2009(Hartman et al , 2010 M37 and Pleiades data sets. The Kepler and CoRoT missions reach lower amplitudes and can detect stars with longer rotation periods, pushing stellar rotation measurements into the solar regime (Basri et al 2011;Garcia et al 2014;Walkowicz and Basri 2013;Nielsen et al 2013;Reinhold et al 2013;McQuillan et al 2014).…”

Section: Stellar Rotation and Spin Downmentioning

confidence: 99%

The Solar-Stellar Connection

Brun¹,

García²,

Houdek³

et al. 2017

Space Sciences Series of ISSI

View full text Add to dashboard Cite

We discuss how recent advances in observations, theory and numerical simulations have allowed the stellar community to progress in its understanding of stellar convection, rotation and magnetism and to assess the degree to which the Sun and other stars share similar dynamical properties. Ensemble asteroseismology has become a reality with the advent of large time domain studies, especially from space missions. This new capability has provided improved constraints on stellar rotation and activity, over and above that obtained via traditional techniques such as spectropolarimetry or CaII H&K observations. New data and surveys covering large mass and age ranges have provided a wide parameter space to confront theories of stellar magnetism. These new empirical databases are complemented by theoretical advances and improved multi-D simulations of stellar dynamos. We trace these pathways through which a lucid and more detailed picture of magnetohydrodynamics of solar-like stars is beginning to emerge and discuss future prospects.

show abstract

The Monitor Project: stellar rotation at 13 Myr

Cited by 67 publications

References 58 publications

Improved angular momentum evolution model for solar-like stars

Improved angular momentum evolution model for solar-like stars

Investigating the rotational evolution of young, low-mass stars using Monte Carlo simulations

The Solar-Stellar Connection

Contact Info

Product

Resources

About