2017年度岡山ユーザーズミーティング

木星自由振動観測プロジェクト
進捗報告
生駒大洋（東京大学）
共同研究：佐藤文衛・井田茂（東工大）・花山秀和・関井隆・泉浦秀行・神戸栄治（天文台）F.-X. Schmider, T. Guillot (OCA)
科研費・基盤研究(A) H29-32年度
ドップラー振動撮像装置を用いた木星表面振動観測：内部構造と起源の解明に向けて（代表：生駒大洋）
2017年9月4日(月) 10:43-10:56，国立天文台三鷹

Conventional Jupiter-Formation Model
Two Separate Phases

Ikoma et al. (2000)

80

Phase 1 - Core growthEnvelope

Mass (Earth mass)

10060… Cores grow via accretionof 10-100km planetesimals.

*** Critical Core Mass ***40

Phase 2 - Envelope growth2000Core1020… Strong gravity ofthe critical core triggers
runaway gas accretion.

Time (Myr)Mass of the core is a clue to the origin of Jupiter.

Cloudy atmosphereEnvelope
Core

Gaseous Hydrogen
Liquid Hydrogen
Metallic HydrogenIce + RockKey Questions
Is a high-density core present atthe center? How massive is it?
Is there a clear boundary b/w core& envelope?
How much heavy elements arecontained in the envelope?
Where does the molecular/metallic
transition occur in the envelope?

)J.J. Fortney, N. Nettelmann
Fortney & Nettelmann (2010, SSRv) w/ Miguel et al. (2016, A&A)

Mass of core [Earth mass],

Conventional Estimate of Core Mass

REOS-3The interior structure
has been inferred frommeasured gravitational
moments.
Gravitational moments aresensitive not to deepenvelope structure, butto outer-envelopestructure.

Total Mass of heavy elements in envelope [Earth mass]

Big uncertainty about internal
composition of JupiterJovian Seismology
Radial displacement⇠r (r, ✓,m, t) = a(r) Y` (✓,- Spherical harmonics sY`m (✓,) = ( 1)

m3

`=0

`=1
`=2
`=3m2) exp( 2⇡i⌫t)2` + 1 (` m)! mP` (cos ✓) exp(im )4⇡ (` + m)!

10123

Jackiewicz+ 12

1.0

Mol. H20.8

25
34

0.6

Met. H+

0.4
0.2
0.0
104147

Core10100
Angular degree`

22 2c(r)4⇡⌫Turning point radiust=2& sound speedrt`(` + 1)

The core is sensed bymodes of frequency > ~2 mHz & low degree.

54103

Acoustic depth [min]Radial distance [RJ=1]

Jovian Seismology

Previous Detection
The SYMPA ProjectPower (m2s-2)

0.15

Gaulme+ 2011`=10.10
0.05
00.5

1.0

1.5

2.0
2.5
3.0
Frequency (mHz)

3.54.04.5

Detected global oscillations of Jupiter!
Two excesses are found around frequenciesof 1.2 mHz and 2.8 mHz.
Frequency spacing ⌫ is ~ 0.16 mHz.

Previous Detection
Modified from Fig. 9 of Gaulme+ 2011

Frequency spacing⌫ [μHz]165

160
LM-SOCP155

LM-A

LM-H4Obs.

05

The inferred value agrees
basically with thetheoretical predictions.
Useful for validating JupitermodelsSCvH-i150

145

Comparison with models! 1
Z RJ
dr⌫= 2c010Core mass [Earth mass]

15

More accurate determinationof Δν can constrain the coremass more definitively.

Jovian Oscillations through radial Velocimetry
ImAging observations at several Longitudes
F.-X. Schmider (Obs. Cote d’Azur), P. I.

JOVIAL Network Observation
Continuous observations from 3 sites> 50% duty cycle over two weeks

National Solar Observatory Observatoire de Calern(France)(United States)

Okayama Observatory (Japan)…188 cm telescope

Ishigaki Observatory (Japan)…105 cm telescope

The Japanese Team
科研費・基盤研究(A) H29-32年度

ドップラー振動撮像装置を用いた木星表面振動観測〜内部構造と起源の解明に向けて〜

研究総括

研究代表者

研究分担者

生駒 大洋(東京大学)

佐藤 文衛(東京工業大学)

木星形成理論構築

木星自由振動観測

木星内部構造推定

研究代表者

研究分担者

研究分担者

生駒 大洋(東京大学)

佐藤 文衛(東京工業大学)

関井 隆(国立天文台)

連携研究者

研究分担者

研究代表者

井田 茂(東京工業大学)

花山 秀和(石垣島天文台) 生駒 大洋(東京大学)
連携研究者

特任研究員

泉浦 秀行(岡山天文台)

國友 正信(東京大学)

連携研究者

神戸 栄治(岡山天文台)

Elevation [deg]Observation in May, 2018
Okayama 188cm

UT / JST (9 May 2018)

Jupiter’s Elevation
Apache point

NiceOkayama

The Instrument
Doppler
SpectroImager
Mach-Zehnder interferometer
Measures the Doppler shift ofreflected solar lines at 517nm
Linear combination of the interferograms
leads to a radial velocity map.
Noise level < 4cm/s in 2 weeks
Velocity accuracy ~ 20m/s/“ in 1h

位相が90度ずつずれた

木星の干渉像Image of JupiterThe Okayama 188cm
TENTATIVE SCHEDULE
2018.3-4
Transport & installof the instrument
Test observation
2018.5Observation

Observation in June, 2019
Okayama 188cm

Ishigaki 105cm

UT / JST (10 June 2019)

UT / JST (10 June 2019)

Summary
The internal structure, especially the massof the core and the distribution of heavy
elements in the envelope, provides crucial
constraints to the origin of Jupiter.
Conventional inference of the interior basedon gravitational moments contains a large
uncertainty regarding the internal composition.
Our network observations of Jovian
oscillations at Okayama/Ishigaki, Nice, & New
Mexico, which are scheduled in May 2018 &June 2019, is expected to narrow down theuncertainty greatly.

Stay tuned!