The non-canonical e olu ion
o s a s in clus e s
S a Dance
Elena Pancino
In oduc ion o Bina y Wo kshop 2025
(Flo ence, Oc obe 2025)
Qui ci me o una s iscia a a di immaginine belle di clus e s, s elle o an i, e in e azioni bina ie
We do no know how s a clus e s o m
We canno explain hei s ella con en
Clocks Templa es T ace s
Ou as ophysical labo a o ies
Di ec ly o indi ec ly used in
a ange o esea ch ields
Labo a o ies
MW: 170 globula clus e s,
>3000 open clus e s
Elena Pancino –A ce i –Oc obe 2025
Two elephan s in he oom
Gaia-ESO da a,
Pancino e al. 2017
Mul iple popula ions
A e ou models and s ella clocks
calib a ed on ue single s a s?
Since 1976
•Elemen a ia ions
•Ho H-bu ning
•S ella gene a ions?
No scena io wo ks
Mul iple s ella gene a ions?
A di e en s a o ma ion mode?
Non-canonical popula ions
Gaia DR3 da a,
Pancino e al., in p ep.
Since 1953
•Bina y byp oduc s
•S ella o a ion
•Also open clus e s
No unde s ood
00.1 0.2 0.3 0.4 0.5
BP-RP (mag)
8
9
10
11
G (mag)
100
200
300
sini (km/s)
Elena Pancino –A ce i –Oc obe 2025
An i-co ela ions
Oldes e idence
Bessell & No is 1976
•Ligh elemen a ia ions – CNO + NeNa + MgAl – Ho H bu ning
•I on-peak and hea y elemen s a y only in some GC (abou 20%)
Pancino e al. 2017
B iley e al. 2005
[Fe/H]=-0.5 dex
[Fe/H]=-1.5 dex
[Fe/H]=-2.5 dex
In globula clus e s
Elena Pancino –A ce i –Oc obe 2025
Mul iple popula ions
Oldes e idence
Lee e al. 1999
Pancino e al. 2000
Sbo done e al. 2011
Pio o e al. 2009
•Ni ogen a ia ions al e he U-band magni udes
•Helium a ia ions al e he V- and I-band ones
Pho ome y is e y e icien o s udy he phenomenon
Bas ian & La do 2018
Milone e al. 2017
Elena Pancino –A ce i –Oc obe 2025
The cu en pa adigm
Obse a ions:
1. Abundance a ia ions in all phases
2. E en in s a s ha canno p oduce hem
In e p e a ion:
1. Tha chemis y comes om ou side
2. Tha chemis y mus su i e e olu ion
•A la ge ac ion o he s a pollu ed
•The s a s o m om pollu ed gas
These a e he wo pilla s o
cu en ly mos explo ed explana ions
1s DU
RGB
bump
S e son e al. 2019
Elena Pancino –A ce i –Oc obe 2025
Non-canonical popula ions
M67 (C edi s: Emily Leine )S a clus e s a o dynamical in e ac ions among s a s
•They con ain a a ie y o non-canonical, o
“exo ic” s ella popula ions …
… blue, ed, yellow s aggle s, sub-subgian s,
li- ich s a s, ex ended MS TO, spli MS,
ho subdwa s, ex eme HB s a s,
o e massi e and unde massi e s a s …
… hen blue lu ke s … and now we also ha e
me al- ich RR Ly ae…
I is a eal jungle, some e en call i a zoo!
Elena Pancino –A ce i –Oc obe 2025
S a s which gained mass
(C edi : Ba y Roal
Ca lsen) Blue s aggle s
•B ig he and blue han TO
•Collisions o mass ans e ?
•T iple sys ems?
•Blue lu ke s
O e massi e s a s
•Found wi h Keple
•In open clus e s
•La ge p opo ions
(B ogaa d
e al 2021)
10% o he s a s in NGC 6791
ha e unde gone mass ans e
(B ogaa d+2021)
Elena Pancino –A ce i –Oc obe 2025
S a s which los mass
Leine e al. (2017)
ESO/L. Calçada,
INAF-Padua/S. Zaggia
Randall e al. (2016)
Red s aggle s & sub-subgian s
• ain e + edde han SGB/RGB
• o a e as o loosing mass
•some a e bina ies CV, LMXB
•in open and globula clus e s
Ho subdwa s and ex eme HB s a s
•Co e He-bu ning
•Ve y li le en elope le
•In he ield: all bina ies
•In GCs: no bina ies, gian spo s
M67
NGC5139
Elena Pancino –A ce i –Oc obe 2025
S a Dance eam and LOC
The name on he badges o he LOC membe s is w i en in RED
I you ha e doub s o ques ions on he wo kshop, please
do eel ee o ask any o us and we will do ou bes o help
Pancino
Tu chi
Rani
Sa acino
Reggiani
Lei inge
Sanna
A dee a
Nedha h
S einbaue
Eche es e
Al a ez
Elena Pancino –A ce i –Oc obe 2025
