putting a stars into context: evolution, environment, and related stars, june 3-7, 2013, moscow m.v....

Putting A Stars into Context:Putting A Stars into Context: Evolution, Environment, and Related Stars, Evolution, Environment, and Related Stars, June 3-7, 2013, Moscow M.V. Lomonosov State University, Moscow, RUSSIAJune 3-7, 2013, Moscow M.V. Lomonosov State University, Moscow, RUSSIA

Abundance Analysis of the Abundance Analysis of the Early Type Members of the Early Type Members of the

Open Cluster M6Open Cluster M6

Tolgahan KILIÇOĞLUAnkara University, Department of Astronomy and Space Sciences, Ankara, Turkey

Richard MONIERLagrange Laboratory, Nice University, Nice, France

LESIA Observatoire de Paris-Meudon, Meudon

Luca FOSSATIArgelander-Institute for Astronomy, Bonn University, Germany


The Open Cluster M6

Introduction The Open Cluster M6

Observation Which equipment?

Deriving Atmospheric Parameters

Photometric methods

Spectral methods

Abundance Analysis Methods to derive abundances

The results

Discussion Star-to-star abundance variations


The Open Cluster M6• Age: 100 30 milion years• Distance: 500 pc• Reddening:

– Johnson UBV [E(B-V)] : 0.15 0.01

(Strobel 1992, Paunzen 2006, Ahumada & Lapaset 2007)

– Geneva 7color [E(b-y)] : 0.13 0.01(Nicolet 1981, North & Cramer 1981)

– Strömgren uvby [E(B2-V1)]: 0.11 0.01(Schnenider 1985)

• 209 members are identified.Rohlfs et al. (1959)Antalova (1972)

NOAO, NASA


Observations

• VLT Telescopes– Flames/Giraffe Spectrograph

• L479.7– R=7800, 4501 – 5078 Å, = 577

• H525.8B– R=25900, 5143 – 5356 Å, = 213

• H572.8– R=24200, 5597 – 5840 Å, = 243

– 120 objects were observed three times.


The Atmospheric Parameters• Strömgren Photometry

– Not applicable.

• Geneva 7color Photometry– Künzli et al. (1997)’s calibrations– CALIB code (North, P., priv. comm.)– Used for 42 members.

• H lines• Excitation Equilibrium• Ionisation Equilibrium


• NGC 6405 94, 13000 500 K, 4.00 0.10 dex

The Atmospheric Parameters

Nor

mal

ized

Flu

x

Wavelength (Å)


• NGC 6405 47, 9400 200 K, 4.20 0.10 dex


Wavelength (Å)

Nor

mal

ized

Flu

x



Wavelength (Å)

Nor

mal

ized

Flu

x

• NGC 6405 47, 9400 K, 4.00 dex



Wavelength (Å)

Nor

mal

ized

Flu

x

• NGC 6405 47, 9200 K, 4.20 dex


• NGC 6405 65, 6700 100 K, 4.20 0.20 dex


Wavelength (Å)

Nor

mal

ized

Flu

x


Model Atmospheres

• ATLAS9 Model Atmospheres (Kurucz 1993, Sbordone et al. 2004, Sbordone 2005)– Teff range: 5900 K – 16000 K

– Log g range: 3.50 – 4.40 dex

• Smalley (2004)’s prescriptions:– For Teff > 8500 K, = 0.00

– For 8500 K > Teff > 7000 K, = 0.50

– For 7000 K > Teff, = 1.25


The abundance analysis• SYNSPEC48SYNSPEC48 (Hubeny & Lanz 1992)• SYNPLOTSYNPLOT (modified)

– Calculating χ² for the observed and synthetic spectra

• Linelist: gfhyperall.dat (Kurucz), Vald, Nist, ...• For B-type stars: For B-type stars: He, (O), Si, (P), (S), FeHe, (O), Si, (P), (S), Fe • For A-type stars: For A-type stars: C, O, Mg, Si, Ca, Sc, Ti, Cr, C, O, Mg, Si, Ca, Sc, Ti, Cr,

Mn, Fe, Ni, Y, BaMn, Fe, Ni, Y, Ba• For F-type stars: For F-type stars: C, Mg, Ca, Sc, Ti, Cr, Mn, Fe,C, Mg, Ca, Sc, Ti, Cr, Mn, Fe,

Ni, Y, BaNi, Y, Ba


The abundance analysis


The abundance analysis• An Am star candidate: NGC 6405 47

(Kılıçoğlu, Monier & Fossati 2012)

– Te = 9400 K

– Log g = 4.20– vsini = 5.1 km/s

– vmic = 2.3 km/s


The abundance analysis• A He weak PGa star candidate: NGC6405 20

(Kılıçoğlu, Monier & Fossati 2012)

• Fundamental Parameters– Te = 15400 500 K

– logg = 4.00 0.2 dex– vsini = 31 3 km/s


The abundance analysis• Double/Multiple Stars: NGC 6405 99


Results / DiscussionsA-type stars

F-type stars

[X/H

][X

/H]

Errors:

Mg, Si, Fe, Ti ~ 0.2 dexC, O, Ca, Sc ~ 0.3 dexY, Ba ~ 0.4 – 0.6 dex

22log

2micgTetotal


DiscussionEffective temperature vs. iron abundance

vsini vs. iron abundance


Discussions• Elemental stratification in

A-type stars?– The competition between

radiative diffusion and mixing mechanisms (rotation, turbulence, meridional mixing, ...)

Gebran & Monier (2008)


Discussions• Elemental stratification in

A-type stars?– The competition between

radiative diffusion and mixing mechanisms (rotation, turbulence, meridional mixing, ...)

• To do list– Evolution models to understand

the chemical evolution• Turcotte et al. (1998, F stars) • Richer et al. (2000, A stars)

Gebran & Monier (2008)


References1. Rohlfs, K., Schrick, K. W., Stock, J. 1959, “Lichtelektrische Dreifarben-Photometrie von NGC 6405 (M6). Mit 3

Textabbildungen”, Zeitschrift für Astrophysik, 47, 15.2. Schneider H. 1985. Stromgren photometry of open clusters. I - NGC 6281, NGC 6405. Astronomy and Astrophysics Supplement

Series. 61, 45-51.3. Antalová, A. 1972. UBV photographic photometry of stars in the region AR1950: 17h03m - 17h41m, Decl1950: -28.8° to -33.4°.

III. The catalogue and identification maps of open star clusters: NGC 6405, NGC 6383, "NGC 6374", AV 2, NGC 6416 and H emissions region: GUM 67(Av 3), GUM 68 (Av 2). Bulletin of the Astronomical Institute of Czechoslovakia, 23, 126.

4. Strobel, A.; Skaba, W.; Proga, D. 1992. Estimation of the ages and distances of open clusters from the Palomar Observatory Sky Survey. Astronomy and Astrophysics Supplement Series, 93, 271-291.

5. Paunzen, E.; Netopil, M.; Iliev, I. Kh.; Maitzen, H. M.; Claret, A.; Pintado, O. I. 2006. CCD photometric search for peculiar stars in open clusters. VII. Berkeley 11, Berkeley 94, Haffner 15, Lyngå 1, NGC 6031, NGC 6405, NGC 6834 and Ruprecht 130. Astronomy and Astrophysics, 454, 171-178.

6. Ahumada, J., Lapasset, E. 2007. New Catalogue of blue stragglers in open clusters. Astronomy and Astrophysics, 463, 789-797.7. Nicolet, B.1981. Geneva photometric boxes. III - Distances and reddenings for 43 open clusters. Astronomy and Astrophysics,

104, 185-197.8. North, P.; Cramer, N. 1981. Ap stars detected in open clusters by the Geneva photometry. International Conference on

Astrophysics, 23rd, Liege, Belgium, June 23-26, 1981, Reports. s. 55-59.9. Künzli, M.; North, P.; Kurucz, R. L.; Nicolet, B. 1997. A calibration of Geneva photometry for B to G stars in terms of Teff, log G

and [M/H]. A & A Supplement series, 122, 51-77.10. Kurucz, R. L. 1993, CD-ROM 13, ATLAS9 Stellar Atmosphere Programs and 2 km/s Grid (Cambridge: Smithsonian Astrophys.

Obs.).11. Sbordone, L., Bonifacio, P., Castelli, F., & Kurucz, R. L. 2004, Memorie della Societa Astronomica Italiana Supplement, 5, 93 12. Sbordone, L., 2005, Memorie della Societa Astronomica Italiana Supplement, 8, 6113. Smalley, B. 2004, “Observations of convection in A-type stars”, IAU Symp., 224, 131. 14. Hubeny, I., Lanz, T., 1992, Accelerated complete-linearization method for calculating NLTE model stellar atmospheres, A&A,

262,501.15. Kılıçoğlu T., Monier R., Fossati, L. 2012, “Abundance analysis of B, A and F dwarfs in the M6 open cluster: Spectrum synthesis

method”, SF2A-2012, 351.16. Kılıçoğlu T., Monier R., Fossati, L. 2012, “Detection of a new phosphorus rich star in the open cluster M6”, SF2A-2012, 355.17. Gebran, M., Monier, R., 2008, Chemical composition of A and F dwarfs members of the Pleiades open cluster, A&A, 483,567.18. Turcotte, S., Richer, J., Michaud, G., 1998. Consistent Evolution of F Stars: Diffusion, Radiative Accelerations, and Abundance

Anomalies, ApJ., 504, 559.19. Richer, J., Michaud, G., Turcotte, S., 2000, “The Evolution of AMFM Stars, Abundance Anomalies, and Turbulent Transport”,

ApJ., 529, 338.

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