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2 edition of Rotation, activity and lithium depletion among late-type stars in young galactic open clusters found in the catalog.

Rotation, activity and lithium depletion among late-type stars in young galactic open clusters

David John James

# Rotation, activity and lithium depletion among late-type stars in young galactic open clusters

## by David John James

Written in English

Edition Notes

Thesis (Ph.D) - University of Birmingham, School of Physics and Astronomy Astrophysics and Space Research, Faculty of Science, 1998.

 ID Numbers Statement by David John James. Open Library OL18073953M

Galactic open clusters and globular clusters are compared with the predictions. I will show that these can be used to reconstruct the initial conditions and the cluster evolution. A. Lanzafame Title: Lithium abundance, activity and rotation in Open Clusters and Young Loose Associations Abstract. Above, a degree wide view of the double star cluster, h (or NGC , on the right) and χ (or NGC , on the left) Persei, a pair of relatively young "open" or "galactic" star clusters located about 7, light years from Earth in the Perseus arm of our galaxy (outwards, relative to the center of the galaxy).The clusters are only separated by a few hundred light years, and because of.

Stars spend about 90% of their existence fusing hydrogen into helium in high-temperature and high-pressure reactions near the core. Such stars are said to be on the main sequence, and are called dwarf ng at zero-age main sequence, the proportion of helium in a star's core will steadily increase, the rate of nuclear fusion at the core will slowly increase, as will the star's. Advisor: R.D. Jeffries; Thesis: Rotation, Activity & Lithium Depletion Among Late-type Stars in Young Galactic Open Clusters. Royal Holloway and Bedford New Title: Project Management Consultant .

New variable stars discovered in the ﬁelds of three Galactic open clusters using the VVV Survey trophysical data for Galactic OCs - among them Antalova1 - which could be identiﬁed in their All-Sky Compiled Catalogue of million stars (ASCC).   () -- Most stars form in clusters. Recent studies of nearby star forming regions find that about three-quarters of their young stars are located in .

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### Rotation, activity and lithium depletion among late-type stars in young galactic open clusters by David John James Download PDF EPUB FB2

Stars in young open clusters (ICICICα Per) do not show any correlation, in the Pleiades cluster a correlation is present: the faster the rotation the less the Lithium depletion.

We look for a correlation between Lithium abundance and rotation period in solar-type stars (G0\dots K0). The result is not unambiguous. Stars in young open clusters (ICICIC Key words: Stars: activity (); Stars: late-type (); Stars: rotation (); Open clusters: individual: IC ( IC ) 1.

Introduction Young open clusters with ages of a few 10 Myr harbour a large number of solar-type stars that are just starting their evolution onto the main sequence.

Their peculiar evolutionary. There is some indication (at the 98% confidence level) that solar-type stars in both clusters, and in the similarly aged NGC cluster, may lack the extreme rotation and activity levels shown.

Request PDF | Membership, rotation, and lithium abundances in the open clusters NGC A and B | High-resolution spectra of 30 late-type and 9 early-type candidate members of the young (˜ On the dispersion in lithium and potassium among late-type stars in young clusters: IC   Abstract.

Using a self-consistent dynamic theory of non-local convection, the atmospheric lithium-abundance depletion values of a series of stellar evolutionarCited by: From a nearly uniform sample of spectroscopic data for large numbers of stars in over 50 open clusters in the third and fourth Galactic quadrants, we derive the speed of Galactic rotation at the solar circle as Θ 0 = +6 km s Future work will include clusters in the other Galactic quadrants and analysis of the local rotation : Peter M.

Frinchaboy, Steven R. Majewski. tions of rotation were found in some clusters [10, 16, ], the general accepted opinion is that galaxy clusters do not rotate. The sparse rotating clusters were found among arbitrar-ily selected cluster samples.

Den Hartog & Katgert [16] found 13 possibly rotating File Size: KB. These stars are cooler, redder, and part of old globular clusters.

Whereas the gas-rich Galactic Disk is the site of ongoing star formation, and so contains stars of all ages, all stars in the Galactic Halo are old. No new stars are forming there and star formation ceased long ago, at least 10 billion years, judging by the stars that are there now.

The light from stars in the disk is dimmed about 2 magnitudes per kiloparsec. all of these c. The light from stars in the disk is redder than their spectral types indicate. Dark silhouettes of material are observed blocking the light from stars. The Galaxy's rotation. Which is characteristic of globular star clusters.

old age and hundreds of thousands of stars, only about 30 ly wide B. no remaining MS stars, but millions of white dwarfs C. only brown dwarfs in a yellow ball ly across D. bright blue main sequence stars, and thousands of them E. a mix of old and young stars, aboutly across. The highest Li abundance observed in 47 Tuc is about dex lower than the lowest Li abundance observed among the un-depleted stars of the metal-poor open cluster NGC The lithium abundances in 47 Tuc, when put into context with observations in other clusters and field stars, suggest that stars that are more metal-rich than [FeH] \sim -1 Cited by:   The distribution of young open clusters in the Galactic plane within 3 kpc from the Sun suggests the existence of the outer ring $$R_{1}R_{2}'$$ in the Galaxy.

The optimum value of the solar position angle with respect to the major axis of the bar, $$\theta_{\mathrm{b}}$$, providing the best agreement between the distribution of open clusters and model particles is \(\theta_{\mathrm{b}}=35 Cited by: 4.

Currently available data on the field of velocities V r, V l, V b for open star clusters are used to perform a kinematic analysis of various samples that differ by heliocentric distance, age, and membership in individual structures (the Orion, Carina-Sagittarius, and Perseus arms).

Based on clusters located within 5 kpc of the Sun with ages up to 1 Gyr, we have determined the Galactic Cited by: Hence, star clusters are perfectly suited for the study of processes linked to stellar structure and evolution such as pulsation, diffusion, rotation, mass-loss, and meridional circulation, to mention a few.

Another advantage to investigate variable stars in open cluster is that one gets light curves simultaneously for many different : Ernst Paunzen, Gerald Handler, Monika Lendl, Bernhard Baumann, Christian Rab, Stefan Meingast, Monik.

Some discussion is provided on how extra galactic star cluster populations and especially their age distributions can be used to gain insight in disruption. es: star clusters, open clusters and associations: general 1. Introduction In the Milky Way the majority of star formation occurs in embedded clusters (Lada & Lada ).

How many stars are located in open (galactic) clusters. 's to 's. Describe the size of the open (galactic) cluster. Differential Rotation- the inner Milky Way is rotating faster than the outer Milky Way.

If the spiral arms were tied to matter they would quickly "wind up" and disappear. We aim at searching new variable stars in the fields of Galactic open clusters. The search is performed using near-infrared data obtained from the VVV Survey.

We discovered new variable stars in the fields of three open clusters (Cepheids, RR Lyr, eclipsing binaries, etc.).Cited by: 5. We perform a comparative analysis of the spatial distribution of young (<50 Myr) open star clusters and field Cepheids with different metallicities.

A significant fraction of young clusters are shown to have low metallicities atypical of field Cepheids. Both types of objects exhibit approximately equal (in magnitude) negative radial metallicity gradients, while their azimuthal metallicity Cited by: 3.

Measurements of lithium in stars of different galactic populations such as young open clusters (α Per, Pleiades, Praesepe, Coma, Hyades), very young stellar associations (Taurus-Auriga, Chamaeleon, Ophiuchus clouds), intermediate and old open clusters (NGCM 67, NGC ), old disc stars and halo stars give us the observational framework from which the galactic evolution of lithium Cited by: 6.The formation of open clusters takes tens of millions of years and an open cluster can have 10 to 10, stars withstellar mass.

Position: In the earth’s galaxy, there are over identified open clusters distributed along the plane of Milky Way with some being as close as light years. Typically, about 10% of the mass of a gas cloud will coalesce into stars before radiation pressure drives the rest away.

Open clusters are very important objects in the study of stellar evolution.