Radial mixing in galactic discs

Sellwood, J. A.; Binney, James

doi:10.1046/j.1365-8711.2002.05806.x

Cited by 954 publications

(1,294 citation statements)

References 57 publications

(85 reference statements)

Supporting

Mentioning

1,244

Contrasting

Unclassified

Order By: Relevance

“…The larger changes in angular momentum of stars (churning) always occur near the corotation resonance that leads to the radial migration of stars of few kpc from their birth radii on a short period, while the effect at the inner/outer Lindblad resonances (blurring) is smaller (Sellwood & Binney 2002;Minchev & Famaey 2010). Through N-body simulations, Fujii & Baba (2012) find that clusters lose (gain) at most 50% of their angular momentum within 1 Gyr.…”

Section: Computation Of Oc Birth-sitesmentioning

confidence: 99%

The evolution of the Milky Way: new insights from open clusters

Reddy¹,

Lambert²,

Giridhar³

2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

We have collected high-dispersion echelle spectra of red giant members in the twelve open clusters (OCs) and derived stellar parameters and chemical abundances for 26 species by either line equivalent widths or synthetic spectrum analyses. We confirm the lack of an age−metallicity relation for OCs but argue that such a lack of trend for OCs arise from the limited coverage in metallicity compared to that of field stars which span a wide range in metallicity and age. We confirm that the radial metallicity gradient of OCs is steeper (flatter) for R gc < 12 kpc (>12 kpc). We demonstrate that the sample of clusters constituting a steep radial metallicity gradient of slope −0.052±0.011 dex kpc −1 at R gc < 12 kpc are younger than 1.5 Gyr and located close to the Galactic midplane (| z| < 0.5 kpc) with kinematics typical of the thin disc. Whereas the clusters describing a shallow slope of −0.015±0.007 dex kpc −1 at R gc > 12 kpc are relatively old, thick disc members with a striking spread in age and height above the midplane (0.5 < | z| < 2.5 kpc). Our investigation reveals that the OCs and field stars yield consistent radial metallicity gradients if the comparison is limited to samples drawn from the similar vertical heights. We argue via the computation of Galactic orbits that all the outer disc clusters were actually born inward of 12 kpc but the orbital eccentricity has taken them to present locations very far from their birthplaces.

show abstract

Section: Computation Of Oc Birth-sitesmentioning

confidence: 99%

The evolution of the Milky Way: new insights from open clusters

Reddy¹,

Lambert²,

Giridhar³

2016

Mon. Not. R. Astron. Soc.

View full text Add to dashboard Cite

show abstract

“…Much of the earlier work indicated that a large scatter in metallicity was seen at all ages, which was part of the motivation to invoke large-scale radial mixing of stars within the disk. This mixing, predicted by Sellwood & Binney (2002), is generated by resonances with the spiral pattern, and is able to move stars from one near-circular orbit to another. It would bring stars from the inner and outer disks, with their different mean abundances, into the solar neighborhood.…”

mentioning

confidence: 97%

Structure and Evolution of the Milky Way

Freeman

2011

Red Giants as Probes of the Structure and Evolution of the Milky Way

View full text Add to dashboard Cite

This review discusses the structure and evolution of the Milky Way, in the context of opportunities provided by asteroseismology of red giants. The review is structured according to the main Galactic components: the thin disk, thick disk, stellar halo, and the Galactic bar/bulge. The review concludes with an overview of Galactic archaeology and chemical tagging, and a brief account of the upcoming HERMES survey with the AAT. The Thin Disk: Formation and EvolutionHere are some of the issues related to the formation and evolution of the Galactic thin disk:• Building the thin disk: its exponential radial structure, and the role of mergers.• The star formation history: chemical evolution and continued gas accretion.• Evolutionary processes in the disk: disk heating, radial mixing.• The outer disk: chemical properties and chemical gradients.Many of the basic observational constraints on the properties of the Galactic disk are still uncertain. At this time, we do not have reliable information about the star formation history of the disk. We do not know how the metallicity distribution and the stellar velocity dispersions in the disk have evolved with time. One might have expected that these observational questions were well understood by now, but this is not yet so. The basic observational problem is the difficulty of measuring ages for individual stars.The younger stars of the Galactic disk show a clear abundance gradient of about 0.07 dex kpc −1 , outlined nicely by the cepheids (Luck et al., 2006). In the outer disk, for the older stars, the abundance gradient appears to be even stronger: the

show abstract

“…This means that the solar system could have been subjected to tidal perturbations that were significantly different from those which characterize its current Galactic environment (Sellwood & Binney 2002). This new perspective and the discovery of many extra solar systems, makes it necessary to study the influence that a Galactic environment, in positions closer to the Galactic center than the solar one.…”

Section: Galaxy Tide On Oort Cloudmentioning

confidence: 99%

Galactic planar tides on the comets of Oort Cloud and analogs in different reference systems. I.

Biasi

Secco

Masi

et al. 2015

A&A

View full text Add to dashboard Cite

A comet cloud analog of Oort Cloud, is probably a common feature around extra solar planetary systems spread out across the Galaxy. Several external perturbations are able to change the comet orbits. The most important of them is the Galactic tide which may re-inject the comets towards the inner part of the planetary system, producing a cometary flux with possible impacts on it. To identify the major factors that influence the comet injection process we organized the work into three papers. Paper I is devoted only to Galactic tide due to mass contribution of bulge, disk and dark matter halo, for different values of parameters for central star and comets. In the present work only planar tides are preliminarly taken into account in order to focus on this component, usually disregarded, that may become no longer negligible in presence of spiral arms perturbation. To check how much the tidal outputs are system independent, their description has been done in three different reference systems: the Galactic one and two heliocentric systems with and without Hill's approximation developed for an axisymmetric potential in 3D-dimensions. The general consistency among the three reference systems is verified and the conditions leading to some relevant discrepancy are highlighted. The contributions from: bulge, disk and dark matter halo are separately considered and their contribution to the total Galactic tide is evaluated. In the other two of the trilogy we will treat the migration of the Sun and the dynamics of Oort Cloud comets due to the total tide and to spiral arms of the Galaxy. One of the main result reached in this paper is that the Hill's approximation turns out to be powerful in predicting the relative importance among the Galactic components producing the tidal perturbation on the Oort Cloud and analogs around new extra solar planetary systems. The main relevance is due to the contribution to the central star circular velocity on the disk due to each Galactic component together with their corresponding velocity logarithmic gradients. Moreover the final results show a strong dependence of the comet perihelion variation on the combination of Galactic longitude and direction of motion. Comet orbits with the same Galactic longitude, but opposite direction of motion, have opposite signs of mean perihelion variation. This dependence is stronger as the Sun-comet system approaches the Galactic center. The harmonic trend of the mean perihelion distance as function of longitude and directions of motion is qualitatively explained on the strength of a simple application of the Lagrange planetary equations.

show abstract

Radial mixing in galactic discs

Cited by 954 publications

References 57 publications

The evolution of the Milky Way: new insights from open clusters

The evolution of the Milky Way: new insights from open clusters

Structure and Evolution of the Milky Way

Galactic planar tides on the comets of Oort Cloud and analogs in different reference systems. I.

Contact Info

Product

Resources

About