Sidang Tugas Akhir

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Astronomy Research Division. Faculty of Mathematics and Natural Sciences. Institut Teknologi Bandung. Page 2. OUTLINE. • Introduction. Effects of WIMP dark ...
4th International Conference on Mathematics and Natural Sciences 2012

Effects of Dark Matter on Stellar Interior and Evolution Sulistiyowati, H. Wulandari, B. Dermawan, M. Ikbal Arifyanto, I. Ibrahim Astronomy Research Division Faculty of Mathematics and Natural Sciences Institut Teknologi Bandung

OUTLINE • Introduction Effects of WIMP dark matter on stars

• Simulation • Result, analysis, and discussion • Conclusions

How does dark matter get into stars? Born with WIMPs

(Spolyar, Freese, & Gondolo, 2008; Freese et al.,2009)

Capture WIMPs later

(Yoon, Iocco, & Akiyama, 2008; Taoso et. al., 2008)

What can dark matter do to stars? WIMP capture by star

WIMP scattering with baryon

Gravitationally bound Accumulated in star core

Additional energy injection Annihilation

Simulation DarkSUSY Gondolo et. al. 2004

+

EZ-Stars Paxton 2004; Eggleton 1971, 1972; Pols et. al. 1995

DarkStars code Scott, Fairbairn, dan Edsjö (2009)

Simulation cont. • WIMP capture 𝐶 𝑡 = 4𝜋

𝑅∗ 0

2



𝑟 𝑑𝑟 0

𝑓 𝑢 𝑤Ω− 𝑣 𝑤 𝑑𝑢 𝑢

• WIMP accumulation in star core • WIMP annihilation and energy injection 𝜖𝑎𝑛𝑛

2𝑎(𝑟, 𝑡)𝑚𝜒 𝑐 2 𝑟, 𝑡 = − 𝜐𝑙𝑜𝑠𝑠 (𝑟, 𝑡) 𝜌∗ (𝑟, 𝑡)

𝜖𝑊𝐼𝑀𝑃 𝑟, 𝑡 = 𝜖𝑎𝑛𝑛 𝑟, 𝑡 + 𝜖𝑡𝑟𝑎𝑛𝑠 𝑟, 𝑡

• Solving fundamental differential equations on stellar structure and evolution

Simulation cont. Started at ZAMS, halted if: 1. Stars leave main sequence (Xc < 10-6) 2. Stars become WIMP-burner, effective energy is produced from WIMP annihilation(Xc < 10-14 M*, log ρc < 10-10, log Tc < 10-10 over 4 consecutive timestep) 3. Stellar age > universe age

Dark matter causes:

Means:

Stars here resemble young

Extending lifetime

Evolutionary tracks:

Conclusions 1. WIMP capture and annihilation rate are higher for: • Higher WIMP ambient density • Higher stellar mass • Lower accreted WIMP mass

2. WIMP effects on main sequence stars: • Decrease central temperature, pressure and density of stars • Suppress Hydrogen burning rate • Extend main sequence lifetime 3. High mass stars suffer less effect from dark matter than low mass stars

Thank You



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