KIAA-Cambridge Workshop
The Formation of Peculiar Stars
Zhanwen Han
(Kunming)
KIAA-Cambridge Workshop
KIAA-Cambridge Workshop
Kunming
Beijing
Nanjing Shanghai
KIAA-Cambridge Workshop
正心问天 寻道兴文
KIAA-Cambridge Workshop
正心问天 寻道兴文
KIAA-Cambridge Workshop
Current Projects
Stellar Evolution Binary Related Objects
Applications of Stellar Evolution
Symbiotics
Blue Stragglers
Hot Subdwarfs
Progenitors of SNe Ia,Companion Stars of SNe Ia 、
CEMP
Contact Binaries
Rapid Mass Loss Model
Initial-Final Mass Relation
Stellar Evolution with Alpha elements enhanced
EPS model
Stellar Populations of Galaxies
Far-UV excess of early-type galaxies
Chemical Yields of Stellar Population
Gravitational Wave Radiation Background of
the Galaxy
Brown Dwarfs
KIAA-Cambridge Workshop
Progenitor Model:
Single Degenerate Model
CO WD + MS
CO WD + RG
Double Degenerate
CO WD + CO WD
KIAA-Cambridge Workshop
Birthrates of SNe Ia from WD+MS
Birth
rate
time
Han, Podsiadlowski, 2004, MNRAS
KIAA-Cambridge Workshop
Humuy: I ½
Livio: DD
WD+AGB
WD+Mira
Delayed dynamically unstable RLOF
Hamuy et al. 2003, Nature
SN Ia 2002ic , Different Progenitor ?
KIAA-Cambridge Workshop
2002ic-like SNe Ia——delayed dynamical unstable RLOF model
Han, Podsiadlowski, 2006, MNRAS
KIAA-Cambridge Workshop
Com
p. Mass
Orb. Period
KIAA-Cambridge Workshop
Properties of Companion Stars of SNe IaHan, 2008, ApJL
Space Velocity
Com
p. Mass
Eff. Temperature
Gravity
KIAA-Cambridge Workshop
Rot. Velocity
Com
p. M
ass
KIAA-Cambridge Workshop
hot subdwarfs
KIAA-Cambridge Workshop
Why hot subdwarfs important ?
• Stellar evolutionary theory
• Stellar seismology
• Distance indicator
• Structure and evolution of the Galaxy
• Far-UV excess (UV-upturn) of early type galaxies (age indicator ?)
KIAA-Cambridge Workshop
Binary model
To explain binary and single hot subdwarfs .
• Han, Podsiadlowski, Maxted, Marsh, Ivanova, 2002, MNRAS, 336, 449
• Han, Podsiadlowski, Maxted, Marsh, 2003, MNRAS, 341, 669
• Han, 2008, A&A, 484, L31
KIAA-Cambridge Workshop
KIAA-Cambridge Workshop
Hot subdwarfs in globular clusters
Extreme Horizontal Branch (EHB) stars
Han, 2008, A&A, Letter
KIAA-Cambridge Workshop
Han, Podsiadlowski, Lynas-Gray, 2007, MNRAS
KIAA-Cambridge Workshop
Brown et al. 2003
KIAA-Cambridge Workshop
GALEX Observations
KIAA-Cambridge Workshop
• Despite its simplicity, our model can reproduce lots of observations
• UV-upturn is universal (from dwarf to giant ellipticals)
• The magnitude of UV-upturn does NOT depend much on metallicity or redshift.
• UV-upturn is NOT an age indicator !
UV-upturn is explained naturally !
KIAA-Cambridge Workshop
Thanks !
KIAA-Cambridge Workshop
Composite Populations:old dominant + younger minor
FUV~ f
Given tmajor, variable f, tminor
8 supernovae in 6 of the 10 quiescent
galaxies
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