simulations of binary accretion and modeling of the ...2015年度の論文tm+ 2015,mnras, 449, 123...

-1000 -500 0 500 1000x (AU)

-1000

-500

0

500

1000

z (A

U)

t = 6.90213E+05 yr, step = 214000tp = 1.76021E+04 yr offset = (-2.84E+04, 1.05E+04) AU

500 AU

(c)

22.5 23.0 23.5 24.0 24.5log column density (cm-2)

Simulations of binary accretion and modeling of the heliosphere

(XC-B)

Matsumoto, T. (Hosei univ)

Saigo, K (Osaka-pref Univ), Takakuwa, S. (ASIAA) 、

Shiota, D. (Nagoiya Univ), Kataoka, R. (NIPR)Miyahara, H. (Musabi), Miyake, S. (Ibaraki-Col. NIT)

平成27年度CfCAユーザーズミーティング 2016年1月29日＠国立天文台水沢キャンパス

2015年度の論文 TM+ 2015,MNRAS, 449, 123

Binary Accretion

Introduction: recent works

• Observations– Radio observations: dynamics of CBD

• Takakuwa+ 14 …. protobinary system, L1551 NE, ALMA• Dutrey+ 15 ....T Tauri binary system, GG Tau, ALMA

– We have to explain these observations.

• Simulations– The recent works are high-resolution two-dimensional sims.

• Artymowicz & Lubow 96 … 3D SPH (early work)• (snip)• Hanawa+ 10 … two-dimensional mesh• Young+ 15 …… two-dimensional SPH

– High-resolution three-dimensional simulation are required.

3

Model and method

4

12 1 Density

Ω = 1

SFUMATO AMR code

• Isothermal gas• Self-gravity is ignored• A circular orbit of stars• FMR in rotating frame• Up to 100 revolutions• Calculation: 512 cores, 1 week

Results (a typical model)

5

q = 0.2, jinf = 1.2,

cs = 0.1, finf = 1.0

mass ratio

sound speed

angular momentum of gas

injection of gas

Ensemble average of 80 - 100 revolutions.Horseshoe orbit @ gap, accretion @ arms

6

Horseshoe orbit

Horseshoe orbit

Accretion Accretion

Stream lines:velocity @ co-rot frame

Surfa

ce d

ensi

ty

c.f., Young+ 15

7

Outflow along arm Horseshoe orbit at gap

Detected by ALMA Cycle 0

Summary of gas flows in CBD and gap

Accretion along arm

Will be detected by ALMA Cycle 2

Non-axisymmetric pattern rotates irrespective of binary parameters

8

80 - 84 revolution

C.f., UY AurHioki+ 07Tang+ 15

surfa

ce d

ensi

ty

Matsumoto in prep

9

4h31m44s7 44s6 44s5 44s4 44s3Right ascension (J2000.0)

18°8′29″

30″

31″

32″

33″

34″D

eclin

atio

n (J

2000

.0)

300 AU

Takakuwa+ 14

ALMA Cycle-0Non-axisymmetric patrern?

Modeling of the Heliosphere

Grand minimum

西暦（年）

Maunderminimum

ThepaintofThames

Solar activity → GCR modulation → climate change

An evidence of the little ice age

“The Frozen Thames, looking Eastwards towards Old London Bridge”Abraham Hondius 1677年 12

現在のテムズ川（1月）

Motivation• To investigate relationship between modulation of CGR

and magnetic field in the heliosphere during grand minimums.

• To make a framework of MHD+GCR for space weather.

電流シート

終端衝撃波

太陽圏界面

弓状衝撃波

地球

Solar wind model is obtained by B obs.

r = R⦿ Field lines (2nd order)

Br(Rs)

Br(R⦿)

Inner boundaryr = 25 R⦿

Source surfacer = 2.5 R⦿

Potential B-field fromWSO obs fs =

✓R�Rs

◆2 Br(R�)

Br(Rs),

Super-radial expansion factor

C.f., Kataoka+ 09, Shiota+ 14

obs day: 2015/5/5

𝑉"# 𝑓" , 𝜌 𝑓" , 𝑝 𝑓"

Results of test calculation (cross section)

-200 -100 0 100 200x (Rsun)

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-100

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z (R

sun)

t = 3.0000000E+02

|v| (km s-1)

300

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y (R

sun)

t = 3.0000000E+02

|v| (km s-1)

300

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450

500

z = 0 plane y = 0 planevelocity velocity

43 cells/block×163 blocks/level= 643 cells/level

Results of test calculation (3d view)

200 R☉

Current sheetBallerina structure

|𝑥|, |𝑦|, |𝑧| ≤ 50×22max 𝑅⊙

𝑙max = 9 のとき 𝑅boundary = 25600𝑅⊙ = 120AU

10数レベルでヘリオポーズをカバーする

𝐵G = 0

Strong scaling

1000 1200 1400 1600 1800 2000 2200Parallel number

400

500

600

700

800

900

1000El

apse

tim

e (s

econ

d)

Idealw/o RefinementRefinement interval = 16Refinement interval = 8Refinement interval = 1

Parallel number

Cal

cula

tion

time

(sec

)Scales up to ~1000 cores.The better performance when lower frequency of refinement.

5123 cells/level×10 levels, 512 steps

Calculation time is estimated to be 40 hours for 1 year of the heliosphere.

7.89E5 mesh / core / sec

Summary

• Binary accretion– Gas flows in the CBD and gap was reproduced.– Gas flows in the CBD were observed by ALMA Cycle 0. – Gas flows in the gap will be resolved by ALMA-Cycle2

• A dynamical model of Heliosphere– A test calculation

• Rotating solar wind model.• Refinement criterion is distance from the Sun. • The current sheet produces ballerina sturcture.

– Performance• AMR level is 10 layers.• Calculations were scaled on 2,048 cores.• Parallel efficiency is estimated as 50% at 5,000 cores.• OpenMP should be implemented for >10,000 cores.