Download Dark Matter and Stars

Asymmetric dark matter
and the Sun
Fabio Iocco
Marie Curie fellow at
Institut d’Astrophysique de Paris
Based on arXiv:1005.5711 (PRD in press)
Taoso, FI, Meynet, Bertone, Eggenberger
Cosmo 2010
Univ. of Tokyo, Japan 27/9/2010
Scattering and capture
Halo WIMPs are captured
Captured WIMPs accumulate
inside the star, thermalize
X
and “sink” to the center
by scattering off the gas of the star
DM Capture
(for the “vanilla” WIMP)
Capture rate C
“Dark Luminosity” inside the star
At equilibrium
WIMPs thermally relaxed within the star:
Distribution
WIMP resilience volume
 point-source
RX109cm<<Rc
Equilibrium timescales are short
Energy transport effects:
scatter of orbiting DM
Seminal literature by:
Gould, Griest, Press,
Raffelt,Salati, Seckel,
Spergel …
The Sun: HE s from DM
[Wikstrom & Edsjo `09]
JCAP; arXiv:0903.2986
Where does this take place (efficiently)?
Galactic Center
is dense in DM
Little DM in our neighborhood
[Ullio et al. `01, Bertone & Merritt `05]
Scattering and transport
Captured WIMPs orbit
and scatter over long
Star
mean free paths
x
x
core
x
DM particles
can efficiently
transport heat
inside the core
x
x
WIMPs and the SUN:
energy transport
self annihilating
DM annihil. & DM transp
o.o.m. smaller nuclear
non annihilating
DM transp
o.o.m. nuclear
lc ≈ 1010 cm, s =10-36 cm2
[Taoso, FI, 2010]
Asymmetric DM and the SUN:
energy transport effects
<sv> ≤ 10-33 cm3/s
[Bottino et al. `02]
asymmetric DM can modify
solar structure at > % level in the core
[Taoso, FI et al. `10]
The WIMPS and Sun:
modifying thermal neutrinos
8B
 produced innermost than 7Be 
modified by asymmetric DM
[Taoso, FI et al. `10]
Exclusion power
using 8B neutrinos
Benchmark  flux [SNO]
fB= 5.046 x 106 cm-2s-1
DfB = 5%
DfB = 25%
(1pb)
See also [Cumberbatch et al. `10]
(helioseismology, weaker diagnostic)
[Taoso, FI et al. `10]
Self-Interacting DM in the Sun
Capture of SI-DM
Limited by geometrical
cross section of DM region
(optical limit)
p r 2c
No sizable effect
on solar composition
disagreement with
[Frandsen & Sarkar `10]
[Taoso, FI, et al. `10]
Conclusions
 Self annihilating DM can not modify the structure of the Sun
 Non annihilating DM can modify the structure of the Sun
 Non annihilating DM induces variation on 8B neutrino flux
 Competitive constraints on SD cross section (low masses)
 More to be addressesd with other type of stars in other environs
Self annihilating DM:
compact objects at the Galactic Centre
Carbon neutron stars
sSI=10-41 cm2
sSI=10-43 cm2
[Moskalenko & Wai `07]
[de Lavallaz & Fairbairn `10]
White dwarves in Globular Clusters
White dwarfs
DENSE and with
no intrinsic energy production
DM profile reconstructed
from baryons/stars
WD, blackbody approx
T*, L*  r*  C*
rDM=104 GeV/cm3
(sample stars from the innermost field)
GC baryon dominated
[Bertone & Fairbairn 08]
SA Inelastic DM
(WD in M4)
rDM=8x102 GeV/cm3
sSI=10-40 cm2
[McCullough & Fairbairn `10]
see also [Hooper et al `10]
Going cool: WIMP burning
(stars
[Fairbairn et al. 08]
have negative specific
heat)
[Iocco et al. 08]
Similar semi-analytical solutions with “cosmions”: Salati & Silk 89
DM burning at the Galactic Center
At the limit of effectiveness
With current upper limits on cross section
[Scott, Fairbairn & Edsjo `09]