Angular momentum regulation in low-mass young stars surrounded by accretion disks

Edwards, Suzan; Strom, S. E.; Hartigan, Patrick; Strom, K. M.; Hillenbrand, Lynne A.; Herbst, W.; Attridge, J. M.; Merrill, K. M.; Probst, Ron; Gatley, I.

doi:10.1086/116646

Cited by 277 publications

(227 citation statements)

References 0 publications

Supporting

Mentioning

208

Contrasting

Unclassified

Order By: Relevance

“…Observational support for this picture includes evidence for a correlation of rotation properties with the presence of disks (Bouvier et al 1993 andEdwards et al 1993). This disk-locking scenario was observationally supported by rotation period studies in the ONC, where Attridge & Herbst (1992) first discovered a bimodal period distribution (with peaks around 2 and 8 days) and Herbst et al (2001Herbst et al ( , 2002, in addition to confirming this, emphasized that it occurs for stars of spectral types earlier than M2.…”

Section: Discussionmentioning

confidence: 94%

“…On the other hand, the observed range of MS rotation rates could be explained if a range in accretion disk lifetimes is assumed. According to Edwards et al (1993), a mechanism proposed by Königl (1991), known as "disk-locking", which consists of a magnetic star-disk interaction, could be responsible for this characteristic period distribution in young stellar clusters. This is the most acceptable picture of the problem, but Matt & Pudritz (2004) pointed out that observations by Stassun et al (1999) and Johns-Krull et al (1999) and theoretical considerations of Safier (1998) have called the standard disk-locking scenario into question.…”

Section: Introductionmentioning

confidence: 99%

See 1 more Smart Citation

Stellar models simulating the disk-locking mechanism and the evolutionary history of the Orion Nebula cluster and NGC 2264

Landin

Mendes

Vaz

et al. 2016

A&A

View full text Add to dashboard Cite

Context. Rotational evolution in young stars is described by pre-main sequence evolutionary tracks including non-gray boundary conditions, rotation, conservation of angular momentum, and simulations of disk-locking. Aims. By assuming that disk-locking is the regulation mechanism for the stellar angular velocity during the early stages of pre-main sequence evolution, we use our rotating models and observational data to constrain disk lifetimes (T disk ) of a representative sample of low-mass stars in two young clusters, the Orion Nebula cluster (ONC) and NGC 2264, and to better understand their rotational evolution. Methods. The period distributions of the ONC and NGC 2264 are known to be bimodal and to depend on the stellar mass. To follow the rotational evolution of these two clusters' stars, we generated sets of evolutionary tracks from a fully convective configuration with low central temperatures (before D-and Li-burning). We assumed that the evolution of fast rotators can be represented by models considering conservation of angular momentum during all stages and of moderate rotators by models considering conservation of angular velocity during the first stages of evolution. With these models we estimate a mass and an age for all stars. Results. The resulting mass distribution for the bulk of the cluster population is in the ranges of 0.2−0.4 M and 0.1−0.6 M for the ONC and NGC 2264, respectively. For the ONC, we assume that the secondary peak in the period distribution is due to high-mass objects still locked in their disks, with a locking period (P lock ) of ∼8 days. For NGC 2264 we make two hypotheses: (1) the stars in the secondary peak are still locked with P lock = 5 days, and (2) NGC 2264 is in a later stage in the rotational evolution. Hypothesis 2 implies in a disk-locking scenario with P lock = 8 days, a disk lifetime of 1 Myr and, after that, constant angular momentum evolution. We then simulated the period distribution of NGC 2264 when the mean age of the cluster was 1 Myr. Dichotomy and bimodality appear in the simulated distribution, presenting one peak at 2 days and another one at 5−7 days, indicating that the assumption of P lock = 8 days is plausible. Our hypotheses are compared with observational disk diagnoses available in the literature for the ONC and NGC 2264, such as near-infrared excess, Hα emission, and spectral energy distribution slope in the mid-infrared. Conclusions. Disk-locking models with P lock = 8 days and 0.2 Myr ≤ T disk ≤ 3 Myr are consistent with observed periods of moderate rotators of the ONC. For NGC 2264, the more promising explanation for the observed period distribution is an evolution with disk-locking (with P lock near 8 days) during the first 1 Myr, approximately, but after this, the evolution continued with constant angular momentum.

show abstract

Section: Discussionmentioning

confidence: 94%

Section: Introductionmentioning

confidence: 99%

Stellar models simulating the disk-locking mechanism and the evolutionary history of the Orion Nebula cluster and NGC 2264

Landin

Mendes

Vaz

et al. 2016

A&A

View full text Add to dashboard Cite

show abstract

“…This indicates that a very efficient mechanism is at work to remove the angular momentum in these stars; the nature of this mechanism is still controversial. Kundurthy et al (2006), see also Edwards et al (1993), claimed that CTTS are slow rotators with circumstellar disks, while WTTS are fast rotators without accretion disks. However, the association of CTTS with slow rotators and WTTS with fast ones is not as yet observationally confirmed.…”

Section: The Angular Momentum Problem Observational Factsmentioning

confidence: 99%

Nonradial and nonpolytropic astrophysical outflows

Sauty

Méliani

Lima

et al. 2011

A&A

View full text Add to dashboard Cite

Context. A large sample of T Tauri stars exhibits optical jets, approximately half of which rotate slowly, only at ten per cent of their breakup velocity. The disk-locking mechanism has been shown to be inefficient to explain this observational fact. Aims. We show that low mass accreting T Tauri stars may have a strong stellar jet component that can effectively brake the star to the observed rotation speed. Methods. By means of a nonlinear separation of the variables in the full set of the MHD equations we construct semi-analytical solutions describing the dynamics and topology of the stellar component of the jet that emerges from the corona of the star. Results. We analyze two typical solutions with the same mass loss rate but different magnetic lever arms and jet radii. The first solution with a long lever arm and a wide jet radius effectively brakes the star and can be applied to the visible jets of T Tauri stars such as RY Tau. The second solution with a shorter lever arm and a very narrow jet radius may explain why similar stars, either weak line T Tauri stars (WTTS) or classical T Tauri stars (CTTS) do not all have visible jets. For instance, RY Tau itself seems to have different phases that probably depend on the activity of the star. Conclusions. First, stellar jets seem to be able to brake pre-main sequence stars with a low mass accreting rate. Second, jets may be visible only part time owing to changes in their boundary conditions. We also suggest a possible scenario for explaining the dichotomy between CTTS and WTTS, which rotate faster and do not have visible jets.

show abstract

“…Edwards et al 1993;Rebull 2001;H2002;Lamm et al 2005;Rebull et al 2006;Cieza & Baliber 2007). While many of them found a rotation-disk correlation for solar and low mass stars (e.g.…”

Section: Introductionmentioning

confidence: 99%

Rotation-disk connection for very low mass and substellar objects in the Orion Nebula Cluster

Rodríguez-Ledesma

Mundt²,

Eislöffel

2010

A&A

View full text Add to dashboard Cite

Aims. Angular momentum (J) loss requires magnetic interaction between the forming star and both the circumstellar disk and the magnetically driven outflows. In order to test these predictions many authors have investigated a rotation-disk connection in pre-main sequence objects with masses larger than about 0.4 M . For brown dwarfs (BDs) this connection was not investigated as yet because there are very few samples available. We aim to extend this investigation well down into the substellar regime for our large sample of ≈80 BDs in the Orion Nebula Cluster, for which we have recently measured rotational periods. Methods. In order to investigate a rotation-disk correlation, we derived near-infrared (NIR) excesses for a sample of 732 periodic variables in the Orion Nebula Cluster with masses ranging between ≈1.5-0.02 M and whose IJHK colors are available. Circumstellar NIR excesses were derived from the Δ[I − K] index. We performed our analysis in three mass bins (>0.4 M , 0.4-0.075 M , and <0.075 M ). Results. We found a rotation-disk correlation in the high and intermediate mass regime, in which objects with NIR excess tend to rotate slower than objects without NIR excess. Interestingly, we found no correlation in the substellar regime. A tight correlation between the peak-to-peak (ptp) amplitude of the rotational modulation and the NIR excess was found however for all objects with available ptp values (<0.4 M ). We discuss possible scenarios which may explain the lack of rotation-disk connection in the substellar mass regime. One possible reason could be the strong dependence of the mass accretion rateṀ on stellar mass in the investigated mass range (Ṁ ∝ M 2 − 2.8 star ), which is expected to result in a corresponding mass dependence ofJ/J.

show abstract

Angular momentum regulation in low-mass young stars surrounded by accretion disks

Cited by 277 publications

References 0 publications

Stellar models simulating the disk-locking mechanism and the evolutionary history of the Orion Nebula cluster and NGC 2264

Stellar models simulating the disk-locking mechanism and the evolutionary history of the Orion Nebula cluster and NGC 2264

Nonradial and nonpolytropic astrophysical outflows

Rotation-disk connection for very low mass and substellar objects in the Orion Nebula Cluster

Contact Info

Product

Resources

About