Scientific workflow in astrophysics:
Testing different sets of isochrones
Schedule - Seminar
• Thursday 05.10. 18:00 - 19:50
• Thursday 12.10. 18:00 - 19:50
• Thursday 19.10. 18:00 - 19:50
• Thursday 26.10. 18:00 - 19:50
• Thursday 02.11. 18:00 - 19:50
• Thursday 09.11. 18:00 - 19:50
• Thursday 16.11. 18:00 - 19:50
• Thursday 23.11. 18:00 - 19:50
• Thursday 30.11. 18:00 - 19:50
• Thursday 07.12. 18:00 - 19:50
• Thursday 14.12. 18:00 - 19:50
• Thursday 21.12. 18:00 - 19:50
Organisation
• First online, but we can meet in person later on if
needed
• All slides and lessons are accessible via the IS
https://is.muni.cz/auth/el/sci/podzim2023/F3501/um/?lang=en
• First, we go through the basics of the topics, and
in parallel, there are some tasks to do
• When we have all the results, we discuss them
• Start writing a paper for Astronomy &
Astrophysics
Topic: seminar - MUNI
Time: Oct 5, 2023 06:00 PM Amsterdam, Berlin, Rome, Stockholm, Vienna
Every week on Thu, until Dec 21, 2023, 12 occurrence(s)
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Oct 12, 2023 06:00 PM
Oct 19, 2023 06:00 PM
Oct 26, 2023 06:00 PM
Nov 2, 2023 06:00 PM
Nov 9, 2023 06:00 PM
Nov 16, 2023 06:00 PM
Nov 23, 2023 06:00 PM
Nov 30, 2023 06:00 PM
Dec 7, 2023 06:00 PM
Dec 14, 2023 06:00 PM
Dec 21, 2023 06:00 PM
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Former seminars
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Topic – this semester
• Get all available isochrones sets from the
literature
• Get cluster parameters from these sets
• Get astrophysical parameters for field stars
from these sets
• Compare and analyse the results from the
different sets
• Write a paper for A&A
Evolution of Stars
Evolution of Stars
The cluster parameters
1. Reddening
2. Distance modulus
3. Age
4. Metallicity
Maeder & Mermilliod (1981, A&A, 93, 136)
Maeder & Mermilliod (1981, A&A, 93, 136)
Different treatment
of convection
An example – Gaia et al.
Dias et al. (2021, MNRAS, 504, 356)
An example – Gaia et al.
Dias et al. (2021, MNRAS, 504, 356)
Distance:V0-MV
AV
k.AV
Turn-off
From the Pre-Main Sequence to
Globular clusters
Turn-off point
Gaia – before and after
A comparison of isochrone sets
• Grocholski & Sarajedini (2003, MNRAS,
345, 1015) compared the following
isochrones:
1.“Padova”: Girardi et al., 2002, A&A, 391, 195
2.Baraffe: Baraffe et al., 1998, A&A, 337, 403
3.“Geneva”: Lejeune & Schaerer, 2001, A&A, 366, 538
4.Y2: Yi et al., 2001, ApJS, 136, 417
5.Siess: Siess et al., 2000, A&A, 358, 593
For Pop II
The location of the
Sun with isochrones
of 5 Gyr
Isochrones by
Siess et al. (1997)
seem “to have
a problem”
Transformation in distances [pc]
• M35: 1148 [916, 1208]; -20% +5%
• M37: 2042 [1905, 2239]; -7% +10%
• NGC 1817: 2692 [2344, 2884]; -13% +7%
• NGC 2477: 2042 [1698, 2089]; -17% +2%
• NGC 2420: 2630 [2399, 3090]; -9% +17%
• M67: 912 [776, 912]; -15% +0%
• Mean values: -13(5)% +7(6)%, for one free parameter!
Isochrones – evolutionary grids
• Isochrones: available for different ages and
photometric systems
• Evolutionary grids: available for different
masses (and photometric systems)