MOSAIC spectroscopy of cluster stars Jorge Meléndez Departamento de Astronomia, IAG, Universidade do São Paulo
Welcome message from author
This document is posted to help you gain knowledge. Please leave a comment to let me know what you think about it! Share it to your friends and learn new things together.
Transcript
MOSAIC spectroscopy of cluster stars
Jorge Meléndez Departamento de Astronomia, IAG, Universidade do São Paulo
How chemically homogeneous are globular clusters?
Important consequences for: - testing model predictions (stellar evolution, stellar nucleosynthesis and globular cluster chemical evolution)
- setting constraints on the polluters (CNONaMgAl)
- understanding the origin & evolution of globular clusters
The globular cluster M80. HST
Many papers with important contributions from VLT+FLAMES Carretta et al.; Gratton et al.; Marino et al.; Yong et al.; etc
Globular cluster science Abundance variations in globular cluster stars
R = 20000 ok
NGC 6752
Globular cluster science Isotopic variations in globular cluster stars
R = 110 000
UVES+VLT
(single object)
Globular cluster science Isotopic variations in globular cluster stars
R ≥ 60 000 for dwarfs, R ≥ 80 000 for giants
-2.5 -2.0 -1.5 -1.0 -0.5
[Fe/H]
26M
g/2
4M
g
0.0
0
.05
0
.10
0
.15
0
.20
24Mg
25Mg
26Mg
M71 giants
R = 100 000
HIRES+Keck
(single object)
Globular cluster science Multiple branches in globular clusters
Globular cluster science Multiple branches in globular clusters
M 22
Globular cluster science Multiple branches in globular clusters and
variations in the heavy elements
7 arcmin
Almost 0.3 dex
variations in Fe
M 22
Globular cluster science Multiple branches in globular clusters
NGC 1851
Globular cluster science Multiple branches in globular clusters
NGC 6397
Globular cluster science Multiple branches in globular clusters
NGC 6752
NGC 6752
R = 20 000 ok
Cosmological lithium problem
Li-6
Li-7
BBN+WMAP
Primordial lithium
BBN
prediction is
about a factor
of 4-5 higher
than Li in field
halo stars
Evidences of Li depletion using
globular cluster stars Korn et al. 2006, Nature
442, 657 Lind et al. 2009
Difussion in
NGC 6397
NGC 6397
Evidences of atomic difussion in globular cluster stars Korn et al. 2006, Nature 442, 657
Difussion in
NGC 6397
VLT+FLAMES
would need 85h
230 h
NGC 6752
7 arcmin
http://www.spiegelteam.de/NGC6752.htm
NGC 6397
7 arcmin
http://imagensdouniverso.blogspot.com.br/2010/04/aglomerado-globular-ngc-6397.html
M 22
7 arcmin
http://apod.nasa.gov/apod/image/0506/m22_cfht_big.jpg
Studying open clusters with MOSAIC
There is not much information on main sequence stars in
OLD open clusters
- What is the evolution of Li ? - Transport mechanisms in stellar interiors
- Chemical signatures of planets?
M 67
Open cluster
Age = 4 Gyr
[Fe/H] = 0
7 arcmin
http://bf-astro.com/images/m67big.jpg
FLAMES/UVES
~ 20 hours needed for
solar twins (V = 14.6) in
M67 Coverage: 480 - 680 nm
R = 47 000, S/N=175
(S/N = 250 rebinned pixel) Precision 0.025 dex
Collinder 261
Age = 6 Gyr
[Fe/H] ~ 0
7 arcmin
http://aladin.u-strasbg.fr
Open cluster
About 180
hours would be
needed with
FLAMES+UVES
Solar twins in Collinder 261 are much fainter
About 150-180 hours would be
needed with FLAMES+UVES
We need the ELT+MOSAIC+HIRES !
VLT+FLAMES
R = 24 000
S/N = 150
230 hours!
VLT+FLAMES/UVES
R = 47 000
S/N = 100
330 hours!
ELT MOSAIC+HIRES
R = 47 000
S/N = 100
Only 10-14 hours!
ELT MOSAIC+HIRES
R = 100 000
S/N = 100
Only 2 nights!
Extremely high precision abundances (0.01 dex) in globular cluster stars: NGC 6752
R = 110 000, S/N > 200
Precision 0.01 dex
Extremely high precision abundances (0.01 dex) in globular cluster stars: NGC 6752
NGC 6752 is chemically
inhomogeneous in all elements!
We can reveal the hidden secrets of globular cluster stars, all we need is
very high resolution (R = 80 000 – 100 000) and high S/N (> 150-200) spectra.
A few (about 10) fibers from ELT/MOSAIC to ELT/HIRES would
open new windows on cluster studies
Related Documents
