Chemical evolution in the Universe: the next 30 years
16-20 Sept, 2013 Castiglione della Pescaia, Italy
Lick/SDSS library v2.0: a new tool to compute model of
stellar populations with variable Alpha element
abundance ratios
C. Morossi, M. Franchini, P. Di Marcantonio
INAF-Osservatorio Astronomico Trieste, Italy
M.L. Malagnini
Dip. Fisica, Univ. Trieste, Italy
& INAF
M. Chavez
INAOE, Mexico
INAF – Osservatorio Astronomico di Trieste
C. Morossi
Lick/SDSS Spectral Indices
INAF – Osservatorio Astronomico di Trieste
C. Morossi
Lick/SDSS library v1.0 (Franchini et al. 2010)
Computed starting from synthetic spectra degraded at R=1800 (like SDSS)
Two grids of HiRes synthetic spectra:
Solar Scaled [ /Fe] = +0.0 (SSA) and -enhanced [ /Fe] = +0.4 (NSSA)
starting from Kurucz atmosphere models (ATLAS9) computed with solar and enhanced ODF’s by Castelli (2003)
using SPECTRUM V.2.75 (Gray and Corbally 1994)
There is full consistency between synthetic spectra and the ODF of the atmosphere models
Teff : 3500-7000 K (250 K step)
log g: 0.5- 5.0 dex (0.5 dex step) [Fe/H]=-2.5,-2.0,-1.5,-1.0,-0.5,
[Fe/H]=-2.5,-2.0,-1.5,-1.0,-0.5,0.0,+0.2,+0.5 (NSSA)
[Fe/H]=-2.5,-2.0,-1.5,-1.0,-0.5,0.0,+0.2,+0.5 (SSA).0,+0.2,+0.5 (SSA)
[Fe/H]=-2.5,-2.0,-1.5,-1.0,-0.5,0.0,+0.2,+0.5 (NSSA)
INAF – Osservatorio Astronomico di Trieste
C. Morossi
Stellar atmospheric parameters
From Lick/SDSS library v1.0 we (Franchini et al. ApJ 2011, 730, 117) derived
the atmospheric parameters of more than 4000 F, G, and K SDSS stars by
comparing synthetic and observed spectral indices
 Indices are negligibly affected by errors in flux calibration and by
reddening
 Narrow-band indices allow the measurement of the intensity of
features of different chemical species separately
 Indices are characterized by higher S/N than the original spectra
 Homogeneous and self-consistent atmospheric parameter estimates
BUT ...
INAF – Osservatorio Astronomico di Trieste
C. Morossi
Lick/SDSS library v1.0 main limitations
• Only 2 values of [ /Fe]
• All  element abundances varying in “lock steps”
• Matching with observed values via ad-hoc calibration
INAF – Osservatorio Astronomico di Trieste
C. Morossi
Is [ /Fe] the same for all the  elements?
The [Mg/Fe] and [Ca/Fe] derived for more than 4000 F, G, and K SDSS-DR7
stars by means of Lick/SDSS library v1.0 are different !
INAF – Osservatorio Astronomico di Trieste
C. Morossi
Lick/SDSS library v2.0 (in preparation)
 Kurucz atmosphere models computed with ATLAS12
 Refined and more complete atomic and molecular line list
 HiRes synthetic spectra computed with SPECTRUM V.2.76e (Gray and Corbally 1994)
several chemical compositions:
Solar Scaled with [Fe/H] from +0.5 to -3.0 with Δ[Fe/H]=0.25 (SSA)
-enhanced with [ /Fe] from +1.0 to -1.5 with Δ[α/Fe]=0.25 (NSSA)
Individual -element enhanced (i.e. Mg, Si, Ca, Ti)
 full consistency between synthetic spectra and atmosphere models
 No need of ad-hoc calibration for most of the synthetic indices
)
INAF – Osservatorio Astronomico di Trieste
C. Morossi
Are the new synthetic indices more reliable?
Comparison with the observed ones requires:
• Good observations
• Accurate estimates of atmospheric stellar parameters
INAF – Osservatorio Astronomico di Trieste
C. Morossi
Good observations
•
The UVES Paranal Observatory Project: A Library of High- Resolution Spectra of Stars
across the Hertzsprung-Russell Diagram (2003)
Bagnulo, S.; Jehin, E.; Ledoux, C.; Cabanac, R.; Melo, C.; Gilmozzi, R
The Messenger (ISSN0722-6691), No.114, p. 10-14
•
The ELODIE Archive (2004)
Moultaka, J.; Ilovaisky, S. A.; Prugniel, P.; Soubiran, C.
The Publications of the Astronomical Society of the Pacific, Volume 116, Issue 821, pp. 693
•
The Indo-US Library of Coudé Feed Stellar Spectra (2004)
Valdes, Francisco; Gupta, Ranjan; Rose, James A.; Singh, Harinder P.; Bell, David J.
The Astrophysical Journal Supplement Series, Volume 152, Issue 2, pp. 251-259.
•
Medium-resolution Isaac Newton Telescope library of empirical spectra - II. The stellar
atmospheric parameters . (2007)
Cenarro, A. J.; Peletier, R. F.; Sánchez-Blázquez, P.; Selam, S. O.; Toloba, E.; Cardiel, N.;
Falcón-Barroso, J.; Gorgas, J.; Jiménez-Vicente, J.; Vazdekis, A
Monthly Notices of the Royal Astronomical Society, Volume 374, Issue 2, pp. 664-690
INAF – Osservatorio Astronomico di Trieste
C. Morossi
Accurate estimates of atmospheric stellar parameters (1)
•
•
•
•
•
•
•
•
•
•
•
The Chemical Evolution of the Galactic Disk - Part One - Analysis and Results Edvardsson, B.;
Andersen, J.; Gustafsson, B.; Lambert, D. L.; Nissen, P. E.; Tomkin, J. < .Astron Astrophys., 275,
101 (1993)>
Abundances and Kinematics of Field Halo and Disk Stars I: Observational Data and Abundance
Analysis Fulbright J.P. . <Astron. J. 120, 1841 (2000)>
The chemical compositions of Galactic disc F and G dwarfs Reddy, Bacham E.; Tomkin, Jocelyn;
Lambert, David L.; Allende Prieto, Carlos <M.N.R.A.S., 340, 304 (2003)>
Stellar chemical signatures and hierarchical galaxy formation. Venn K.A., Irwin M., Shetrone M.D.,
Tout C.A., Hill V., Tolstoy E. <Astron. J., 128, 1177-1195 (2004)>
Alpha-, r-, and s-process element abundance trends in the Galactic thin and thick disks T. Bensby, S.
Feltzing, I. Lundstrom, and I. Ilyin <Astron. Astrophys. 433l, 185 (2005)>
Giants in the local region. Luck R.E., Heiter U. <Astron. J., 133, 2464-2486 (2007)>
Photospheric CNO abundances of solar-type stars. Takeda Y., Honda S. <Publ. Astron. Soc. Jap.,
57, 65-82 (2005)>
Fundamental parameters and elemental abundances of 160 F-G-K stars based on OAO spectrum
database. Takeda Y. <Publ. Astron. Soc. Jap., 59, 335-356 (2007)>
A holistic approach to carbon-enhanced metal-poor stars. Masseron T., Johnson J.A., Plez B., Van
Eck S., Primas F., Goriely S., Jorissen A. <Astron. Astrophys., 509, A93 (2010)>
Homogeneous photospheric parameters and C abundances in G and K nearby stars with and without
planets. Da Silva R., Milone A., Reddy B.E. <Astron. Astrophys. 526, A71 (2011)>
…
INAF – Osservatorio Astronomico di Trieste
C. Morossi
Accurate estimates of atmospheric stellar parameters (2)
The comparison of our results with published high-resolution analysis results shows that
some of the latter may be affected by systematic errors and/or a lack of self-consistency.
Ionizat ion fract ions
1
f II
1
f III
NI
NII NIII
+
+
NII NII
NII
NI NII
NII
NIII
=
+
+
.
NII NIII NIII NIII
=
(7.11)
(7.12)
Elect rons per nucleus
E=
Ne
=
N nuclei
z N zf I I (z)
+ 2 z N zf I I I (z)
,
z Nz
(7.13)
Pressure rat io
Pg (N ions + N at oms + N e) kT
(N nuclei + N e) kT
E+ 1
=
=
=
Pe
N ekT
N ekT
E
Pe = Pg
E
.
E+ 1
INAF – Osservatorio Astronomico di Trieste
(7.14)
(7.15)
C. Morossi
Accurate and complete atomic and molecular line list (1)
INAF – Osservatorio Astronomico di Trieste
C. Morossi
Accurate and complete atomic and molecular line list (22)
•
•
•
•
•
Individual element abundancies
Self-consistent models and
spectra
Empirical log gf’s
Different microturbulence
velocity for giants and dwarfs
INAF – Osservatorio Astronomico di Trieste
C. Morossi
Preliminary results based on 222 “bona-fide” stars (1)
INAF – Osservatorio Astronomico di Trieste
C. Morossi
Preliminary results based on 222 “bona-fide” stars (2)
INAF – Osservatorio Astronomico di Trieste
C. Morossi
Chemical evolution in the Universe: the next 30 years
16-20 Sept, 2013 Castiglione della Pescaia, Italy
Thank you
INAF – Osservatorio Astronomico di Trieste
C. Morossi