The alignment is in their stars: on the spin-alignment of stars in star clusters

Rey-Raposo, Ramon; Read, Justin I.

doi:10.1093/mnrasl/sly150

Cited by 17 publications

(10 citation statements)

References 26 publications

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“…Below 0.7 M , not enough material is accreted to overcome the randomizing effect of turbulence, which would contribute most of the remaining 50% of the cloud's kinetic energy 4 . This energy balance is similar to what was found to produce alignment on a larger spatial scale (resolution 0.1 pc) by the simulations of Rey-Raposo & Read (2018). These authors suggest that the mixed results from observational studies of spin alignment could all be consistent if the alignment is stronger in higher-mass clusters.…”

Section: Physical Interpretations Of M35 Groupingsupporting

confidence: 81%

Stellar Spins in the Pleiades, Praesepe, and M35 Open Clusters

Healy,

McCullough,

Schlaufman

2021

Preprint

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We analyze spectroscopic and photometric data to determine the projected inclinations of stars in three open clusters: the Pleiades, Praesepe and M35. We determine the sin i values of 42, 35 and 67 stars in each cluster respectively, and from their distributions we find that isotropic spins and moderate alignment are both consistent with the Pleiades and Praesepe data. While it is difficult to distinguish between these scenarios for a single cluster, an ensemble of such distributions may facilitate a distinction. The M35 inclination distribution is most consistent with a superposition of isotropic and anisotropic spins, the source of which could be systematic error or a physical grouping of aligned stars. We also study internal cluster kinematics using radial velocities and proper motions. Our kinematics analysis reveals significant plane-of-sky rotation in Praesepe, with a mean velocity of 0.132 ± 0.022 km s −1 in a counterclockwise direction.

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Section: Physical Interpretations Of M35 Groupingsupporting

confidence: 81%

Stellar Spins in the Pleiades, Praesepe, and M35 Open Clusters

Healy,

McCullough,

Schlaufman

2021

Preprint

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“…The generally advocated explanation for the alignment of stellar rotation axes (and aligned binary orbital spins) in clusters is that the stars were born within a giant molecular cloud (GMC) that contained significant amounts of angular momentum, which was inherited by the stars as they formed (e.g. Corsaro et al 2017;Rey-Raposo & Read 2018). If the alignment of stars/binaries is strong at birth it persists within a cluster, as extremely close, i.e.…”

Section: Introductionmentioning

confidence: 99%

Linking the rotation of a cluster to the spins of its stars: the kinematics of NGC 6791 and NGC 6819 in 3D

Kamann

Bastian

Gieles

et al. 2018

Monthly Notices of the Royal Astronomical Society

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The physics governing the formation of star clusters is still not entirely understood. One open question concerns the amount of angular momentum that newly formed clusters possess after emerging from their parent gas clouds. Recent results suggest an alignment of stellar spins and binary orbital spins in star clusters, which support a scenario in which clusters are born with net angular momentum cascading down to stellar scales. In this paper, we combine Gaia data and published line of sight velocities to explore if NGC 6791 and NGC 6819, two of the clusters for which an alignment of stellar spins has been reported, rotate in the same plane as their stars. We find evidence for rotation in NGC 6791 using both proper motions and line of sight velocities. Our estimate of the inclination angle is broadly consistent with the mean inclination that has been determined for its stars, but the uncertainties are still substantial. Our results identify NGC 6791 as a promising follow-up candidate to investigate the link between cluster and stellar rotation. We find no evidence for rotation in NGC 6819.

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“…Specifically, Corsaro et al (2017) showed that the strong spin alignment is realized if the initial rotational energy of the proto-cluster is significant. In addition, Rey-Raposo & Read (2018) confirmed the spin alignment for the proto-cluster, whose initial condition is taken from a larger disc-galaxy simulation. In reality, however, the competition among the global rotation, turbulence and magnetic field in real star-forming regions is much more complex, and needs to be unveiled individually from the precise observational data.…”

Section: Introductionmentioning

confidence: 56%

Search for Alignment of Disk Orientations in Nearby Star-Forming Regions: Lupus, Taurus, Upper Scorpius, $ρ$ Ophiuchi, and Orion

Aizawa,

Suto,

Oya

et al. 2020

Preprint

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Spatial correlations among proto-planetary disk orientations carry unique information on physics of multiple star formation processes. We select five nearby star-forming regions that comprise a number of proto-planetary disks with spatially-resolved images with ALMA and HST, and search for the mutual alignment of the disk axes. Specifically, we apply the Kuiper test to examine the statistical uniformity of the position angle (PA: the angle of the major axis of the projected disk ellipse measured counterclockwise from the north) distribution. The disks located in the star-forming regions, except the Lupus clouds, do not show any signature of the alignment, supporting the random orientation. Rotational axes of 16 disks with spectroscopic measurement of PA in the Lupus III cloud, a sub-region of the Lupus field, however, exhibit a weak and possible departure from the random distribution at a 2σ level, and the inclination angles of the 16 disks are not uniform as well. Furthermore, the mean direction of the disk PAs in the Lupus III cloud is parallel to the direction of its filament structure, and approximately perpendicular to the magnetic field direction. We also confirm the robustness of the estimated PAs in the Lupus clouds by comparing the different observations and estimators based on three different methods including sparse modeling. The absence of the significant alignment of the disk orientation is consistent with the turbulent origin of the disk angular momentum. Further observations are required to confirm/falsify the possible disk alignment in the Lupus III cloud.

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The alignment is in their stars: on the spin-alignment of stars in star clusters

Cited by 17 publications

References 26 publications

Stellar Spins in the Pleiades, Praesepe, and M35 Open Clusters

Stellar Spins in the Pleiades, Praesepe, and M35 Open Clusters

Linking the rotation of a cluster to the spins of its stars: the kinematics of NGC 6791 and NGC 6819 in 3D

Search for Alignment of Disk Orientations in Nearby Star-Forming Regions: Lupus, Taurus, Upper Scorpius, $ρ$ Ophiuchi, and Orion

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