Rolf Kudritzki SS 2015 2. Stellar evolution – a crash course
Extragalactic stellar distance indicators need to be bright advanced stages of stellar evolution
• Red Giant Star (SFB) • Tip of Red Giant Branch (TRGB) • Horizontal Branch – RR Lyrae • post-AGB stars, Planetary Nebulae • Cepheid Stars • Blue Supergiant Stars
1 Rolf Kudritzki SS 2015 Evolution of low mass stars 0.5M M 2.5M main sequence (MS): H core burning à Red Giant Branch (RGB): H shell burning à He-flash: ignition of He core burning à Tip of RGB (TRGB) à Horizontal Branch (HB): He core burning H burning shell RR Lyrae pulsators à Asymptotic Giant Branch (AGB): He burning shell H burning shell àpost-AGB (pAGB): hot Central Stars of PN (CSPN) à White Dwarfs (WD): no energy sources, cooling
supernovae in binaries 2 Rolf Kudritzki SS 2015
Maeder, 2009 all low mass stars ignite He-flash at almost the same luminosity à tip of red giant branch but there is a metallicity dependence 3 Rolf Kudritzki SS 2015
He-flash after flash stars on HB with central He burning and H burning shell Maeder, 2009 all low mass stars ignite He-flash at almost the same luminosity à tip of red giant branch but there is a metallicity dependence 4 Rolf Kudritzki SS 2015 interior structure during evolution
He-flash hydro- dynamic
Maeder, 2009
the nuclear H-burning shell moves outwards until
He-burning ignites in the degenerate He-core 5 Concepcion 2007 NGC 300 Cycle 11 HST/ACS imaging imaging Cycle11HST/ACS NGC 300 agrees with Cepheids Cepheids with agrees ApJ et al., 2005, Kudritzki Bresolin, Rizzi, TRGB from Distance NGC4258 ComparisonwithMASER distanceto Concepcion 2007 Mager Mager et al. (2008) NGC 300 Cycle 11 HST/ACS imaging imaging Cycle11HST/ACS NGC 300
TRGB M. agrees with Cepheids Cepheids with agrees ApJ et al., 2005, Kudritzki Bresolin, Rizzi, TRGB from Distance
Salaris (theory (theory new) TRGB distance (m (Humphreys et al. 2013) MASER distance (m - - M) M)
, MIAPP 2014 , MIAPP 0 0 =29.40 =29.51
0.06 0.05
your name your 0.06 0.05
TRGBRolf Kudritzki detection SS 2015 (maximum likelihood methods)
LF parametrised as
‘noisy’ edge detection response
The fitted parameters are
mTRGB = 21.79 [21.76, 21.83], RGB slope a = 0.36 [0.30, 0.43]
RGB jumpb = 0.44 [0.38,0.50] Makarov et al. 2006 your name AGB slope c = 0.13 [0.03, 0.24] M. Salaris, MIAPP 2014 8 Rolf Kudritzki SS 2015
after the hydrodynamic He-flash stars with central He-burning and a H-burning shell assemble on the
Horizontal Branch (HB)
HB stars have roughly the same He-core mass
but different envelope masses à Teff sequence
9 Rolf Kudritzki SS 2015 HORIZONTAL BRANCH MORPHOLOGY
your name M. Salaris, MIAPP 2014 10 Rolf Kudritzki SS 2015 globular cluster CMD
Hansen & Kawaler, 1994 11 Rolf Kudritzki SS 2015 globular cluster CMD
RR Lyrae pulsators in HB
Hansen & Kawaler, 1994 12 RolfRR Kudritzki Lyrae starsSS 2015 as distance indicators and stellar tracers RR Lyrae variables
M4
Initial mass (MS): ~0.8-0.9 Msun
Mass (HB): ~0.6-0.8 Msun
Horizontal Branch Core He + Shell H burning (HB)
[Fe/H] ~ -2.5 – 0.0 (Smith, 2005)
Old: >10 Gyr (GCs, halo, bulge) Main Sequence (MS) HB Maruzio’s talk
Stetson, VFB et al. (2014)
Guiseppe Bono, MIAPP 132014 DistanceRolf Kudritzki determination SS 2015 to M4 with optical, NIR and MIR photometry of RR Lyrae M4 CMDs
14 Vittorio Francesco Braga Garching, MIAPP, 11/6/2014 Rolf Kudritzki SS 2015
HB evolution
Maeder, 2009
15 Rolf Kudritzki SS 2015 HORIZONTAL BRANCH Core He-burning Ingredients: phase in old He-core mass at He-ignition Convective-core mixing stellar populations Bolometric corrections Star Formation histories/RGB mass loss
your name16 M. Salaris, MIAPP 2014 Rolf Kudritzki SS 2015 internal structure of AGB star
Maeder, 2009
17 Rolf Kudritzki SS 2015 AGB and post-AGB evolution
CSPN
WD
18 Rolf Kudritzki SS 2015 Evolution of intermediate mass stars 2.5M M 8.0M main sequence (MS): H core burning à Red Giant Branch (RGB): H shell burning à no He-flash: normal ignition of He core burning on RGB à blue loops during He core burning Cepheid pulsators à Asymptotic Giant Branch (AGB): He burning shell H burning shell àpost-AGB (pAGB): hot Central Stars of PN (CSPN) à WD cooling sequence supernova in binaries
19 Rolf Kudritzki SS 2015
evolution of a 7 Msun star
Maeder, 2009 20 Rolf Kudritzki SS 2015 pAGB evolution note: heavy influence of mass-loss,
for instance, 7 Msun star has only 1 Msun left evolution time much faster for luminous objects
Maeder, 2009 pAGB core mass – luminosity relationship
simple fit formula by Paczynski, 1970 L M =5.29 104 0.52 L M ✓ ◆
21 Rolf Kudritzki SS 2015
evolution of a 7 Msun star
Maeder, 2009 22 Rolf Kudritzki SS 2015
evolution of a 7 Msun star
Cepheid instability strip
Maeder, 2009 23 Rolf Kudritzki SS 2015 instability strip
Hayashi limit of low mass fully convective stars
main sequence
24 Rolf Kudritzki SS 2015 Evolution of massive stars M 8.0M main sequence (MS): H core burning à blue supergiants (BSG): H shell burning à red supergiants (RSG): normal ignition of He core burning
à M < 15 Msun blue loops during He core burning Cepheid pulsators à post RSG evolution leads to à iron core collapse supernovae
25 ideal to to ideal const. L,M~ Athens M ≥ -7 stars normal Brightest 2013 Blue supergiants – objects in transition transition Blue supergiants – objects in B1–A4
at visual light: • • • • • • distances laws extinction extinction history SF grad. abundance compos. chemical
10 of galaxies of t ev 5 ~ 10 ~ ..10 V -10 mag -10 ≥ determine
6 3 L yrs yrs sun
MIAPP 2014 Brightest stars IR beacons in universe: red red beaconsIR universe: in B1–A4
at infrared light: infrared at K–M K–M Coma cluster Localbeyond Group out to Keck/VLT, TMT/E-ELT à à dominate lines atomic spectroscopy: J-band resolution medium MOS possible MOS supported AO Advantage: enormous potential with enormous res. medium spectra ok
-8 ≥ M supergiants
J -11 mag -11 ≥
Rolf Kudritzki SS 2015
structure of a massive star shortly before iron core SN collapse
Maeder, 2009
28 Rolf Kudritzki SS 2015 The bright and beautiful death of many stars: Supernovae
Maeder, 2009
29 Rolf Kudritzki SS 2015
light curves of supernova types and peak magnitudes
Maeder, 2009
30 Rolf Kudritzki SS 2015 The bright and beautiful death of many stars: Supernovae
Maeder, 2009
31 Rolf Kudritzki SS 2015
structure of a massive star shortly before iron core SN collapse
Maeder, 2009
32 Introduction Rolf Kudritzki SS 2015 Type IIP supernovae - progenitors
Several direct detections of progenitors (e.g. Smartt et al. 2009): mostly red supergiants
Mass range ~9 to ~18 M⊙ Core-collapse explosions of massive, H-rich stars
Image: Mattila et al. 2010
33 Stefan Taubenberger (MPA) Distance measurements with Type IIP supernovae Observational data II: SNe IIP at intermediate redshift Rolf Kudritzki SS 2015 SNe IIP at the GTC
34 Stefan Taubenberger (MPA) Distance measurements with Type IIP supernovae Rolf Kudritzki SS 2015
Phenomenology
● Strong Hydrogen lines --> Type II classification
● A long Plateau in their lightcurve
● A sharp fall
● A radioactive tail
35 Rolf Kudritzki SS 2015
Phenomenology
● Strong Hydrogen lines --> Type II classification
● A long Plateau in their lightcurve
● A sharp fall
● A radioactive tail
Olivares et al. 2010 36 Rolf Kudritzki SS 2015 SNe IIP in a nutshell
● The duration of the plateau is ● The SN event is generated usually of the order of ~100 by the core-collapse of a days, ranging between 80 massive star and 120 days ● Progenitors are usually Red ● The initial velocity of the Supergiants (RSG, in some ejecta is of the order of 1-2 x cases we have a BSG, such 10^4 km/s as SN 1987A)
● The initial temperature is of ● Their masses are expected the order of 1-2 x 10^4 K to be up to 25-30 M , but on ● Peak luminosities commonly the basis of the progenitors range between Mv = -15.5 analysis, the accepted limit is and Mv = -18.5 mag --> how of the order of 15-18 M ... can we use them as distance
indicators? ...Until now... 37 Rolf Kudritzki SS 2015 The bright and beautiful death of many stars: Supernovae
Maeder, 2009
38 Rolf Kudritzki SS 2015 SNe Ia: Far-Reaching Candles
• CO White Dwarf in binary pushed to Chandrasekhar limit (fundamental physics) Mass transfer, companion, time scales not well understood.
Most uniform standard candle at this luminosity scale
• Empirical and theoretical calibrations give MV=-19 mag, explain yield of IME • Identified by strong Si II, absence of H in spectra, come in late/early type hosts
39 A. Riess, 2012, Naples WS Rolf Kudritzki SS 2015 Surveying the Universe with Type Ia Supernovae
NOAO 4m image of SN 2011fe in M101 (T.A. Rector, SN 2014J in M82 (Marco Burali, Osservatorio MTM Pistoia) H. Schweiker & S. Pakzad NOAO/AURA/NSF)
Saurabh W. Jha MIAPP The Extragalactic Distance Scale May 28, 2014 40 Rolf Kudritzki SS 2015 SNIa background physics
all stars with
CSPN M 8M evolve into the cooling sequence of White Dwarfs WD
41 Rolf Kudritzki SS 2015 cooling sequence of WDs
V.Weidemann and collaborators 42 White Dwarfs: extremely narrow mass distribution
MWD 0.6M h i⇡ without mass-loss stars with such masses cannot have evolved from the main sequence within Hubble time
from the HRDs of open clusters we know that all stars with 0 . 8 M M 8 M have formed WDs The mass spectrum observed can be roughly explained by IMF and stellar evolution with mass-loss applying Reimers – formula Note: no WD with masses M 1 . 4 M !!! Rolf Kudritzki SS 2015 The Physics of White Dwarfs the equation of state (EOS) of WDs is different from normal stars because of their much higher densities: 0.6 solar masses confined within earth-like radius
mean particle distance << de Broglie wavelength quantum nature (fermions!) of matter important: 1. Pauli principle: only one particle per quantum state 2. Fermi distribution of energies instead Maxwell/ Boltzmann 3. different EOS
44 Rolf Kudritzki SS 2015 h B = p2⇡mkT de Broglie wavelength N 1 1 3 n = = 3 r0 = n particle separation V r0 1 energy distribution f(✏)= ( ⌘+ ✏ ) e kt +1 2 1.21 B 2 degeneracy parameter ⌘ = n 3 ↵ r / for B r0 ✓ 0 ◆ ↵ =2 spin degeneracy of electrons
45 Rolf Kudritzki SS 2015
strong degeneracy of free electrons in WD electrons provide pressure acting against gravity different EOS
46 Rolf Kudritzki SS 2015
1 f(✏)= ( ⌘+ ✏ ) e kt +1
✏/kT 2 3 ✏ ne f ⇠ Fermi energy
5 3 WD EOS: degenerate matter P ne ⇠ pressure de-coupled from temperature
47 Rolf Kudritzki SS 2015 Mass – radius relationship of WDs dP M = G r ⇢ hydrostatic equilibrium dr r2 2 dP P0 Pc Pc M M = ⇢¯ P (1) dr ⇠ R 0 R ⇠ R2 c ⇠ R4 M ⇢¯ ⇠ R3 5 5 M 3 on the other hand: EOS P ⇢¯3 (2) c ⇠ ⇠ R5 1 combine (1) and (2) R M 3 ⇠ WD radii shrink with increasing mass!!!! 48 Rolf Kudritzki SS 2015
The Chandrasekhar limit of WDs 2 1 2 3 R M 3 ⇢¯ M ✏f ⇢ ⇠ ⇠ ⇠ with higher mass Fermi energy increases 2 and particles become relativistic ✏f mec 2 2 2 p 1 v 1 ✏ = m c (1 + ) 2 2 0 2 p = m0v(1 2 ) m0c c relationship between energy and momentum p changes
4 2 relativistic P = A2⇢ 3 (1 B2⇢ 3 ) EOS at higher mass
49 Rolf Kudritzki SS 2015
The Chandrasekhar limit of WDs M 2 M combining eq (1) P = A and ⇢ = B0 0 R4 R3 with relativistic EOS yields 1 3 B 1 M at the 0 3 R = 1 M 1 Chandrasekhar 2 MCh B2 r mass MCh the 3 radius is zero 2 A2 2 MCh = B0 1.4M A ⇡ ✓ 0 ◆ no higher masses than MCh possible !!! 50 Rolf Kudritzki SS 2015 WD Mass radius relationship relativistic degeneracy
4 Close to the Chandreasekhar limit: P ⇢ 3 We will show in the next chapter ⇠ that such configurations are unstable
collaps and explosive carbon burning Supernova explosion 51 Rolf Kudritzki SS 2015
Scenario for SNIa supernova explosions
WD in binary system is accreting mass approaching Chandrasekhar limit and explodes as SNIa
Since explosion happens always at same mass, released energy (luminosity) should be the same
Bright standard candle !! ??
52 Rolf Kudritzki SS 2015 SNe Ia: Far-Reaching Candles
• CO White Dwarf in binary pushed to Chandrasekhar limit (fundamental physics) Mass transfer, companion, time scales not well understood.
Most uniform standard candle at this luminosity scale
• Empirical and theoretical calibrations give MV=-19 mag, explain yield of IME • Identified by strong Si II, absence of H in spectra, come in late/early type hosts
53 A. Riess, 2012, Naples WS Rolf Kudritzki SS 2015 Surveying the Universe with Type Ia Supernovae
NOAO 4m image of SN 2011fe in M101 (T.A. Rector, SN 2014J in M82 (Marco Burali, Osservatorio MTM Pistoia) H. Schweiker & S. Pakzad NOAO/AURA/NSF)
Saurabh W. Jha MIAPP The Extragalactic Distance Scale May 28, 2014 54 Rolf Kudritzki SS 2015 What is a Type Ia Supernova?
intermediate mass elements are fused from C and O during the explosion ejecta travels at ~10,000 km/s
Fe Si Fe March 14, 1997 Ca S May 18, 1998 Si
strong evidence that SN Ia are explosions of carbon-oxygen white dwarfs
but big questions about companion star, SN 1998bu in M96 white dwarf mass and explosion process55 S.W. Jha, 2014, MIAPP WS May 18, 1998 Rolf Kudritzki SS 2015 The Groundbreaking Work: Calán/Tololo 1996AJ....112.2391H 1996AJ....112.2398H
Hamuy et al. (1996a,b) 56 S.W. Jha, 2014, MIAPP WS Rolf Kudritzki SS 2015 Standardizing the Candles
SN Ia are standardizable candles, with emprically derived corrections:
light curve-shape correction (aka the Phillips 1993 relation)
color-correction (including dust reddening/extinction, e.g. Riess et al. 1996, 1999)
light curve fitters (in use today): MLCS2k2 (Jha, Riess, & Kirshner 2007) SALT2 (Guy et al. 2007) SiFTO (Conley et al. 2008) BayeSN (Mandel et al. 2009, 2011) SNooPy (Burns et al. 2011) Gaussian Process (Kim et al. 2013, 2014) ... 57 Krisciunas et al. (2006) S.W. Jha, 2014, MIAPP WS 6
Rolf Kudritzki SS 2015 S.W. Jha, 2014, MIAPP WS MLCS2k2MLCS2k2 light-curve light curve fits fits “scene-modeled” multi-color light curves, with fits for light curve shape and dust extinction KAITHoltzman et BVRI al. (2008) photometry SNANA: KesslerGaneshalingam et al. (2009b) Jha, etRiess, al. & (2010) Kirshner (2007) SN 2005ff z=0.09 SN 2005fb z=0.18 SN 2005fr z=0.29 SN 2005gq z=0.39
600 75 2000 200
400 50 1000 100 200 25
0 g 0 g 0 g 0 g
800 300 150 2000 600 200 100 400 1000 100 200 50
0 r 0 r 0 r 0 r
2000 200 Flux Flux 600 Flux Flux 200 400 1000 100 Si 100 200
0 i 0 i 0 i 0 i
-20 -10 0 10μ20 =30 33.4640 50 60 ± 0.07-20 mag-10 0 10 20 μ30 =40 33.450 60 9 ± 0.-2010-10 mag0 10 20 30 40 50 60 -20 -10 0 10 20 30 40 50 60 T - 53634.7 T - 53632.8 T - 53633.4 T - 53646 SNobs 1999cp and SN 2002cr,obs both in NGC 5468 obs 58 obs Fig. 1.— Light curves for four SDSS-II SNe Ia at different redshifts: SN 2005ff at z = 0.09, SN 2005fb at z = 0.18, SN 2005fr at z = 0.29, and SN 2005gq at z = 0.39. The passbands are SDSS g (top), r (middle), and i (bottom). Points are the SMP flux measurements (flux = 10(11−0.4m), where m is the SN magnitude) with 1 σ photometric errors indicated. Solid curves show the best-fit mlcs2k2 model fits (see 5.1), and dashed curves give the 1 σ error bands± on the model fits. The Modified Julian Date (MJD) under each set of light curves is§the fitted time of peak brightness ±for rest-frame B-band.
-20 -10 0 10 20 30 40 50 60 -20 -10 0 10 20 30 40 50 60 -20 -10 0 10 20 30 40 50 60 -20 -10 0 10 20 30 40 50 60
-20 -10 0 10 20 30 40 50 60 -20 -10 0 10 20 30 40 50 60 -20 -10 0 10 20 30 40 50 60 -20 -10 0 10 20 30 40 50 60 Rolf Kudritzki SS 2015 Standardizing the Candles
Jha, Riess, & Kirshner (2007)
Si
~6 to 10% distance precision per object -- average this down with pN59 S.W. Jha, 2014, MIAPP WS Rolf Kudritzki SS 2015 q0, 1998: High-z SNe Ia; Acceleration (q0<0), Dark Energy!
Riess et al. 2007
Not just supernovae require “dark energy”… 60 A. Riess, 2012, Naples WS Rolf Kudritzki SS 2015
61 Rolf Kudritzki SS 2015
62