Download Astroparticle physics 1. stellar astrophysics and solar neutrinos

Astroparticle physics
1. stellar astrophysics and solar
neutrinos
Alberto Carramiñana
Instituto Nacional de Astrofísica, Óptica y Electrónica
Tonantzintla, Puebla, México
Xalapa, 2 August 2004
Stellar classification
• Spectroscopic lines  need for spectral classification.
• Types OBAFGKM  temperature sequence.
Spectral classification
• Spectral line strengths
following Saha law.
HR diagram
• Hertzsprung (1905):
correlation between
spectral type ( colour
 temperature) and
absolute magnitudes
( luminosities).
• Russell (1914): first
color-magnitude (HR)
diagram.
Luminosity
classes
•
•
•
•
•
•
Ia: luminous supergiants
Ib: less luminous...
II: bright giants.
III: normal giants.
IV: subgiants.
V: main sequence
(dwarfs).
• VI,sd: subdwarfs
• D: white dwarfs.
Sun is a G2V star
Hipparcos nearby stars
L = 4R2Te4
Mass – luminosity relation
• Masses measured / estimated in binary stars.
Approx
L  M4
Modelling stellar strcuture
• Basic equations
(assumptions):
– mass conservation
– hydrostatic equilibrium
• a polytrope can now be built
(before thermodynamics!)
– equation of state
(gas & radiation)
– energy transport
(radiative &
convective)
– energy production
Mass composition
•  = mean molecular weight
• X = hydrogen, Y = helium, Z = “metals”
• Stellar evolution models:
X(t), Y(t), Z(t).
 1/2
 1/15.5
Stellar energy production
• Nuclear reactions:
collision and strong
force capture vs
Coulomb repulsion.
– Maxwell distribution
vs tunelling penetration
function: Gamow peak.
Gamow peak depends on temperature
and composition of colliding nuclei.
Solar p-p Gamow peak
Hydrogen
burning:
pp chains
• Proton-proton:
– I:
– II:
– III:
CNO chains and He burning
• Hydrogen burning can also proceed through the
temperature sensitive CNO chain
• Helium burning requires higher temperatures
At 108K 
Stellar models
• Stellar models input: M & {X, Y, Z}
• Solar reaction are pp and CNO (<8%).
• More massive star models have to
incorporate he-burning and -captured
creations to Ne (medium mass) or
reactions up to Fe.
Stellar evolution
From Iben (1967)
The standard solar model
• M = 1 M, X=0.73, Y=0.25, Z=0.02
• X=0.7078, Y=0.2734 (Bahcall & Pinsonneault 2004)
Solar evolution
• Helium enrichment at core  higher temp.
Solar
Neutrinos
predicted
Solar neutrino
predictions and
measurements
Neutrino oscillations
• Neutrino flavor eigenstates as superposition of
mass eigenstates.
• In vacuum and/or matter (MSW effect).
• Oscillations confirmed with KamLAND.
Neutrino oscillations
• Vacuum or matter (MSW effect)?
Vacuum - Matter transitions
P
1
0.5
0
E
MSW
Vacuum
e survival probability:
Low E  MSW dominated
High E  vacuum dominated
Neutrino
oscillation
parameters