On the Origin of the Kinematic Distribution of the Subparsec Young Stars in the Galactic Center

AbstractWe performed a self-consistent N-body simulation of star clusters in the Galactic center (GC), taking into account the collisions of stars and formation of an intermediate-mass black hole (IMBH). We find that if an IMBH forms in the cluster, it carries young stars to the GC by a 1:1 resonance.

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Galactic structure from infrared studies

Symposium - International Astronomical Union ◽

10.1017/s0074180900014297 ◽

1979 ◽

Vol 84 ◽

pp. 105-111 ◽

Cited By ~ 1

Author(s):

J. L. Puget ◽

G. Serra ◽

C. Ryter

Keyword(s):

Galactic Center ◽

Star Formation Rate ◽

Formation Rate ◽

Far Infrared ◽

Mass Function ◽

Infrared Emission ◽

Initial Mass Function ◽

Young Stars ◽

Infrared Studies ◽

Red Giant

Star densities on a galactic scale are traced by far infrared emission of dust heated by young stars and by the 2.4 μm radiation of stars in the red giant phase. Coherent results are obtained, pointing to a very strong star formation rate during the last ∼200 My in a ring 5 kpc from the galactic center. A steepening of the initial mass function compared to that observed in the solar vicinity is also suggested.

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The effect of dark matter on stars at the Galactic center: The paradox of youth problem

International Journal of Modern Physics D ◽

10.1142/s0218271820500522 ◽

2020 ◽

Vol 29 (08) ◽

pp. 2050052

Author(s):

Ebrahim Hassani ◽

Reza Pazhouhesh ◽

Hossein Ebadi

Keyword(s):

Black Hole ◽

Dark Matter ◽

Galactic Center ◽

Young Stars ◽

Evolutionary Models ◽

Massive Black Hole ◽

Physical Conditions ◽

Dm Effect ◽

Evolutionary Paths ◽

Evolutionary Simulations

Stars that evolve near the Galactic massive black hole show strange behaviors. The spectroscopic features of these stars show that they must be old. But their luminosities are much higher than the amounts that are predicted by the current stellar evolutionary models, which means that they must be active and young stars. In fact, this group of stars shows signatures of old and young stars, simultaneously. This is a paradox known as the “paradox of youth problem” (PYP). Some people tried to solve the PYP without supposing dark matter (DM) effects on stars. But, in this work, we implemented Weakly Interacting Massive Particles (WIMPs) annihilation as a new source of energy inside such stars. This implementation is logical for stars that evolve at high DM density environments. The new source of energy causes stars to follow different evolutionary paths on the H-R diagram in comparison with classical stellar evolutionary models. Increasing DM density in stellar evolutionary simulations causes the deviations from the standard H-R diagrams becomes more pronounced. By investigating the effects of WIMPs density on stellar structures and evolutions, we concluded that by considering DM effects on stars at the Galactic center, it is possible to solve the PYP. In addition to DM effect, complete solutions to PYP must consider all extreme and unique physical conditions that are present near the Galactic massive black hole.

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Getting a Kick out of the Stellar Disk(s) in the Galactic Center

Proceedings of the International Astronomical Union ◽

10.1017/s1743921308015780 ◽

2007 ◽

Vol 3 (S246) ◽

pp. 275-276 ◽

Cited By ~ 1

Author(s):

H. B. Perets ◽

G. Kupi ◽

T. Alexander

Keyword(s):

High Velocity ◽

Galactic Center ◽

Stellar System ◽

Young Stars ◽

Stellar Disk ◽

Ob Stars ◽

The Galaxy ◽

Young Clusters

AbstractRecent observations of the Galactic center revealed a nuclear disk of young OB stars, in addition to many similar outlying stars with higher eccentricities and/or high inclinations relative to the disk (some of them possibly belonging to a second disk). Binaries in such nuclear disks, if they exist in non-negligible fractions, could have a major role in the evolution of the disks through binary heating of this stellar system. We suggest that interactions with/in binaries may explain some (or all) of the observed outlying young stars in the Galactic center. Such stars could have been formed in a disk, and later on kicked out from it through binary related interactions, similar to ejection of high velocity runaway OB stars in young clusters throughout the galaxy.

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PROPERTIES OF THE REMNANT CLOCKWISE DISK OF YOUNG STARS IN THE GALACTIC CENTER

The Astrophysical Journal ◽

10.1088/0004-637x/783/2/131 ◽

2014 ◽

Vol 783 (2) ◽

pp. 131 ◽

Cited By ~ 90

Author(s):

S. Yelda ◽

A. M. Ghez ◽

J. R. Lu ◽

T. Do ◽

L. Meyer ◽

...

Keyword(s):

Galactic Center ◽

Young Stars

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The “Paradox of Youth”: Young Stars in the Galactic Center

Revealing the Heart of the Galaxy ◽

10.1017/cbo9781139856546.009 ◽

2013 ◽

pp. 115-128

Author(s):

Robert H. Sanders

Keyword(s):

Galactic Center ◽

Young Stars

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An outward motion of young stars with respect to old stars

Symposium - International Astronomical Union ◽

10.1017/s007418090001456x ◽

1979 ◽

Vol 84 ◽

pp. 242-242

Author(s):

Arthur R. Upgren

Keyword(s):

Galactic Center ◽

Population Group ◽

Young Stars ◽

Mean Motion ◽

Solar Motion ◽

Local Standard ◽

Outward Motion ◽

M Stars ◽

F Stars ◽

Van Vleck

Space motions are calculated for 145 dK2-M2 stars with radial velocities and with parallaxes and proper motions determined and published at the Van Vleck Observatory. The stars are divided into young and old disk components kinematically and also according to the age-sensitive CaII emission intensities. Rigorous solutions for the solar motion and velocity ellipsoid were calculated for each population group using three methods of weighting errors in parallax, proper motion and radial velocity. All methods show a mean motion of the young stars outward away from the galactic center of about ten km/sec when referred to the old stars. Details are presented by Upgren (1978). The conclusion appears to confirm an outward motion suggested by Kerr (1962) from 21-cm observations. It is reasonable to inquire whether a similar outward motion can be seen in the space motions of other stars. Unlike the Van Vleck parallaxes combined with the most rigorous of the weighting methods used here, earlier results may be too insensitive to measure such a motion. Nonetheless a search of some of the existing literature shows that a small outward motion is consistent with sources so far examined. Of the motion solutions listed by Delhaye (1965) only two involve space motions of stars covering most of the main sequence. For stars with velocity dispersions similar to ours, both studies show a small outward motion of the order of five km/sec (for the A dwarfs relative to the generally older F and G dwarfs). The A dwarfs brighter than 5m.5 (Eggen 1965) have a planar motion distribution very similar to our young dK-M stars and both groups possess a mean motion close to the basic and standard solar motions. These last are mostly based on young stars and the solar motion should be reexamined relative to stars of all ages. It might be worthwhile to redetermine the mean motions of stars for which age-dependent parameters are now available, such as the F-stars with uvby measures or the giants with DDO photometry, since the local standard of rest appears to be a function of stellar age. This study was supported by grant AST77-26554 of the National Science Foundation.

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Young stars in the Galactic center

Proceedings of the International Astronomical Union ◽

10.1017/s1743921314000593 ◽

2013 ◽

Vol 9 (S303) ◽

pp. 211-219

Author(s):

Jessica R. Lu ◽

Andrea M. Ghez ◽

Mark R. Morris ◽

Will Clarkson ◽

Andrea Stolte ◽

...

Keyword(s):

Star Formation ◽

Galactic Center ◽

Large Population ◽

Mass Function ◽

Initial Mass Function ◽

Young Stars ◽

Solar Neighborhood ◽

Tidal Forces ◽

Photometric Measurements ◽

Central Parsec

AbstractThe central parsec of our Galaxy hosts not only a supermassive black hole, but also a large population of young stars (age <6 Myr) whose presence is puzzling given how inhospitable the region is for star formation. The strong tidal forces require gas densities many orders of magnitude higher than is found in typical molecular clouds. Kinematic observations of this young nuclear cluster show complex structures, including a well-defined inner disk, but also a substantial off-disk population. Spectroscopic and photometric measurements indicate the initial mass function (IMF) differs significantly from the canonical IMF found in the solar neighborhood. These observations have led to a number of proposed star formation scenarios, such as an infalling massive star cluster, a single infalling molecular cloud, or cloud-cloud collisions. I will review recent works on the young stars in the central parsec and discuss connections with young nuclear star clusters in other galaxies, such as M31, and with star formation in the larger central molecular zone.

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