Research activity information

• Evolution of a Water-rich Atmosphere Formed by a Giant Impact on an Earth-sized Planet

  Kenji Kurosaki, Yasunori Hori, Masahiro Ogihara, Masanobu Kunitomo

  Abstract The atmosphere of a terrestrial planet that is replenished with secondary gases should have accumulated hydrogen-rich gas from its protoplanetary disk. Although a giant impact blows off a large fraction of the primordial atmosphere of a terrestrial planet in the late formation stage, the remaining atmosphere can become water-rich via chemical reactions between hydrogen and vaporized core material. We find that a water-rich postimpact atmosphere forms when a basaltic or CI chondrite core is assumed. In contrast, little postimpact water is generated for an enstatite chondrite core. We investigate the X-ray- and UV-driven mass loss from an Earth-mass planet with an impact-induced multicomponent H₂–He–H₂O atmosphere for Gyr. We show that water is left in the atmosphere of an Earth-mass planet when the low flux of escaping hydrogen cannot drag water upward via collisions. For a water-dominated atmosphere to form, the atmospheric mass fraction of an Earth-mass planet with an oxidizing core after a giant impact must be less than a few times 0.1%. We also find that Earth-mass planets with water-dominated atmospheres can exist at semimajor axes ranging from a few times 0.1 au to a few au around a Sun-like star, depending on the mass-loss efficiency. Such planets are important targets for atmospheric characterization in the era of JWST. Our results indicate that efficient mixing between hydrogen and rocky components during giant impacts can play a role in the production of water in an Earth-mass planet.

  American Astronomical Society, Oct. 2023, The Astrophysical Journal, 957(2) (2), 67 - 67

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Giant Impact Events for Protoplanets: Energetics of Atmospheric Erosion by Head-on Collision

  Kenji Kurosaki, Shu-ichiro Inutsuka

  Abstract Numerous exoplanets with masses ranging from Earth to Neptune and radii larger than Earth have been found through observations. These planets possess atmospheres that range in mass fractions from 1% to 30%, reflecting the diversity of atmospheric mass fractions. Such diversities are supposed to be caused by differences in the formation processes or evolution. Here, we consider head-on giant impacts onto planets causing atmosphere losses in the later stage of their formation. We perform smoothed particle hydrodynamic simulations to study the impact-induced atmosphere loss of young super-Earths with 10%–30% initial atmospheric mass fractions. We find that the kinetic energy of the escaping atmosphere is almost proportional to the sum of the kinetic impact energy and self-gravitational energy released from the merged core. We derive the relationship between the kinetic impact energy and the escaping atmosphere mass. The giant impact events for planets of comparable masses are required in the final stage of the popular scenario of rocky planet formation. We show it results in a significant loss of the atmosphere, if the impact is a head-on collision with comparable masses. This latter fact provides a constraint on the formation scenario of rocky planets with substantial atmospheres.

  American Astronomical Society, Sep. 2023, The Astrophysical Journal, 954(2) (2), 196 - 196

  [Refereed]

  Scientific journal

  Link to Kobe Univ. Repository (Kernel)


• Size evolution of close-in super-Earths through giant impacts and photoevaporation

  Yuji Matsumoto, Eiichiro Kokubo, Pin-Gao Gu, Kenji Kurosaki

  The Kepler transit survey with follow-up spectroscopic observations has discovered numerous super-Earth sized planets and revealed intriguing features of their sizes, orbital periods, and their relations between adjacent planets. For the first time, we investigate the size evolution of planets via both giant impacts and photoevaporation to compare with these observed features. We calculate the size of a protoplanet, which is the sum of its core and envelope sizes, by analytical models. $N$-body simulations are performed to evolve planet sizes during the giant impact phase with envelope stripping via impact shocks. We consider the initial radial profile of the core mass and the initial envelope mass fractions as parameters. Inner planets can lose their whole envelopes via giant impacts, while outer planets can keep their initial envelopes since they do not experience giant impacts. Photoevaporation is simulated to evolve planet sizes afterward. Our results suggest that the period-radius distribution of the observed planets would be reproduced if we perform simulations in which the initial radial profile of the core mass follows a wide range of power-law distributions and the initial envelope mass fractions are $\sim0.1$. Moreover, our model shows that the adjacent planetary pairs have similar sizes and regular spacings, with slight differences from detailed observational results such as the radius gap.

  Sep. 2021, The Astrophysical Journal, 923(1) (1), 81, English

  [Refereed]

  Scientific journal


• Formation of giant planets with large metal masses and metal fractions via giant impacts in a rapidly dissipating disk

  Masahiro Ogihara, Yasunori Hori, Masanobu Kunitomo, Kenji Kurosaki

  According to planetary interior models, some giant planets contain large metal masses with large metal-mass fractions. HD 149026b and TOI-849b are characteristic examples of these giant planets. It has been suggested that the envelope mass loss during giant impacts plays a key role in the formation of such giant planets. The aim of the present letter is to propose a mechanism that can explain the origin of such giant planets. We investigate the formation of giant planets in a rapidly dissipating disk using N-body simulations that consider pebble accretion. The results show that although the pebble isolation mass is smaller than the metal mass (> 30 Earth masses) in some giant planets, the interior metal mass can be increased by giant impacts between planets with the isolation mass. Regarding the metal fraction, the cores accrete massive envelopes by runaway gas accretion during the disk-dissipation phase of 1-10 Myr in a disk that evolves without photoevaporation. Although a large fraction of the envelope can be lost during giant impacts, the planets can reaccrete the envelope after impacts in a slowly dissipating disk. Here, we demonstrate that, by photoevaporation in a rapidly dissipating disk, the runaway gas accretion is quenched in the middle, resulting in the formation of giant planets with large metal-mass fractions. The origins of HD 149026b and TOI-849b, which are characterized by their large metal-mass fractions, can be naturally explained by a model that considers a disk evolving with photoevaporation.

  EDP Sciences, Mar. 2021, Astronomy & Astrophysics, 648, L1 - L1, English

  [Refereed]

  Scientific journal


• The Exchange of Mass and Angular Momentum in the Impact Event of Ice Giant Planets: Implications for the origin of Uranus

  Kenji Kurosaki, Shu-ichiro Inutsuka

  Uranus has a tilted rotation axis, which is supposed to be caused by a giant impact. In general, an impact event also changes the internal compositional distribution and drives mass ejection from the planet, which may provide the origin of satellites. Previous studies of the impact simulation of Uranus investigated the resultant angular momentum and the ejected mass distribution. However, the effect of changing the initial condition of the thermal and compositional structure is not studied. In this paper, we perform hydrodynamics simulations for the impact events of Uranus-size ice giants composed of a water core surrounded by a hydrogen envelope using two variant methods of the smoothed particle hydrodynamics. We find that the higher entropy target loses its envelope more efficiently than the low entropy target. However, the higher entropy target gains more angular momentum than the lower entropy target since the higher entropy target has more expanded envelope. We discuss the efficiency of angular momentum transport and the amount of the ejected mass and find a simple analytical model to roughly reproduce the outcomes of numerical simulations. We suggest the range of possible initial conditions for the giant impact on proto-Uranus that reproduces the present rotation tilt of Uranus and sufficiently provides the total angular momentum of the satellite system that can be created from the fragments from the giant impact.

  Nov. 2018, The Astronomical Journal, 157(1) (1), 13, English

  [Refereed]

  Scientific journal


• Luminosities and thermal evolutions of ice giants by condensation in early atmospheres

  Kurosaki K., Ikoma M.

  現在の惑星放射は惑星の形成時における過去の集積の記録を反映しており，惑星形成プロセスを制約する上で重要である．惑星は高温の初期状態から大気からの放射によって冷却していく．したがって，大気の状態は惑星の冷却効率に影響を与える．これまでの巨大惑星の冷却では大気の組成は進化を通して不変であると仮定していた．しかし，巨大氷惑星では，形成初期において重元素に富む大気を持っていたことが，惑星形成論から示唆されている．これら重元素は低温環境下では凝縮すると考えられる水，アンモニア，メタンを含み，これらの成分が大気の温度構造に影響を与える．本研究は凝縮による惑星放射と惑星熱進化への影響を定量的に調べた．凝縮による潜熱解放によって大気の温度を維持し，高い惑星放射を維持することにより惑星の冷却効率が上がることを示した．このことは，天王星の放射強度が理論的な推定よりも小さいという問題に重要な示唆を与える，また，重元素に富んだ大気を持つ巨大氷惑星は中間赤外で明るくなることもわかり，太陽系外の巨大氷惑星の直接撮像にとっても重要な示唆を与えることができた．

  The Japanese Society for Planetary Sciences, Mar. 2018, Planetary People - The Japanese Society for Planetary Sciences, 27(1) (1), 28 - 39, Japanese

  [Refereed]

  Scientific journal


• Acceleration of Cooling of Ice Giants by Condensation in Early Atmospheres

  Kenji Kurosaki, Masahiro Ikoma

  The present infrared brightness of a planet originates partly from the accretion energy that the planet gained during its formation and hence provides important constraints to the planet formation process. A planet cools down from a hot initial state to the present state by losing energy through radiative emission from its atmosphere. Thus, the atmospheric properties affect the planetary cooling rate. Previous theories of giant planet cooling assume that the atmospheric composition is unchanged throughout evolution. Planet formation theories, however, suggest that the atmospheres especially of ice giants are rich in heavy elements in the early stages. Those heavy elements include condensable species such as water, ammonia, and methane, which are expected to have a great impact on atmospheric temperature and, thus, radiative emission through latent heat release. In this study we investigate the effect of such condensation on the planetary emission flux and quantify the impact on the cooling timescale. We then demonstrate that the latent heat of those species keeps the atmosphere hot and thus the emission flux high for billions of years, resulting in acceleration of the cooling of ice giants. This sheds light on the long-standing problem that Uranus is much less bright than theoretically predicted and is different in brightness from Neptune in spite of similarity in mass and radius. Also, we find that young ice giants with highly enriched atmospheres are much brighter in mid-infrared than those with unenriched atmospheres. This provides important implication for future direct imaging of extrasolar ice giants.

  Apr. 2017, The Astrophysical Journal, 153(6) (6), 260, English

  [Refereed]

  Scientific journal


• Multi-band, Multi-epoch Observations of the Transiting Warm Jupiter WASP-80b

  Akihiko Fukui, Yui Kawashima, Masahiro Ikoma, Norio Narita, Masahiro Onitsuka, Yoshifusa Ita, Hiroki Onozato, Shogo Nishiyama, Haruka Baba, Tsuguru Ryu, Teruyuki Hirano, Yasunori Hori, Kenji Kurosaki, Kiyoe Kawauchi, Yasuhiro H. Takahashi, Takahiro Nagayama, Motohide Tamura, Nobuyuki Kawai, Daisuke Kuroda, Shogo Nagayama, Kouji Ohta, Yasuhiro Shimizu, Kenshi Yanagisawa, Michitoshi Yoshida, Hideyuki Izumiura

  WASP-80b is a warm Jupiter transiting a bright late-K/early-M dwarf, providing a good opportunity to extend the atmospheric study of hot Jupiters toward the lower temperature regime. We report multi-band, multi-epoch transit observations of WASP-80b by using three ground-based telescopes covering from optical (g', Rc, and Ic bands) to near-infrared (NIR; J, H, and Ks bands) wavelengths. We observe 5 primary transits, each of which in 3 or 4 different bands simultaneously, obtaining 17 independent transit light curves. Combining them with results from previous works, we find that the observed transmission spectrum is largely consistent with both a solar abundance and thick cloud atmospheric models at 1.7$\sigma$ discrepancy level. On the other hand, we find a marginal spectral rise in optical region compared to the NIR region at 2.9$\sigma$ level, which possibly indicates the existence of haze in the atmosphere. We simulate theoretical transmission spectra for a solar abundance but hazy atmosphere, finding that a model with equilibrium temperature of 600 K can explain the observed data well, having a discrepancy level of 1.0$\sigma$. We also search for transit timing variations, but find no timing excess larger than 50 s from a linear ephemeris. In addition, we conduct 43 day long photometric monitoring of the host star in the optical bands, finding no significant variation in the stellar brightness. Combined with the fact that no spot-crossing event is observed in the five transits, our results confirm previous findings that the host star appears quiet for spot activities, despite the indications of strong chromospheric activities.

  Jun. 2014, The Astrophysical Journal, 790(2) (2), 108, English

  [Refereed]

  Scientific journal


• Starspots - Transit Depth Relation of the Evaporating Planet Candidate KIC 12557548b

  Hajime Kawahara, Teruyuki Hirano, Kenji Kurosaki, Yuichi Ito, Masahiro Ikoma

  Violent variation of transit depths and an ingress-egress asymmetry of the transit light curve discovered in KIC 12557548 have been interpreted as evidences of a catastrophic evaporation of atmosphere with dust (M_p gtrsim 1 M_oplus/Gyr) from a close-in small planet. To explore what drives the anomalous atmospheric escape, we perform time-series analysis of the transit depth variation of Kepler archival data for ~ 3.5 yr. We find a ~ 30% periodic variation of the transit depth with P1 = 22.83 pm 0.21 days, which is within the error of the rotation period of the host star estimated using the light curve modulation, Prot = 22.91 pm 0.24 days. We interpret the results as evidence that the atmospheric escape of KIC 12557548b correlates with stellar activity. We consider possible scenarios that account for both the mass loss rate and the correlation with stellar activity. X-ray and ultraviolet (XUV)-driven evaporation is possible if one accepts a relatively high XUV flux and a high efficiency for converting the input energy to the kinetic energy of the atmosphere. Star-planet magnetic interaction is another possible scenario though huge uncertainty remains for the mass loss rate.

  Aug. 2013, The Astrophysical Journal Letters, 776(1) (1), L6, English

  [Refereed]

  Scientific journal


• Impact of photoevaporative mass loss on masses and radii of water-rich sub/super-Earths

  Kenji Kurosaki, Masahiro Ikoma, Yasunori Hori

  Recent progress in transit photometry opened a new window to the interior of super-Earths. From measured radii and masses, we can infer planetary internal compositions. It has been recently revealed that super-Earths are diverse in composition. Such a diversity is thought to arise from diversity in volatile content. The stability of the volatile components is to be examined, because hot super-Earths undergo photo-evaporative mass loss. While several studies investigated the impact of photo-evaporative mass loss on hydrogen-helium envelopes, there are few studies as to the impact on water-vapor envelopes. To obtain theoretical prediction to future observations, we also investigate the relationships among masses, radii, and semimajor axes of water-rich sub/super-Earths that have undergone photo-evaporative mass loss. We simulate the interior structure and evolution of sub/super-Earths that consist of a rocky core surrounded by a water envelope, including mass loss due to the stellar XUV-driven energy-limited hydrodynamic escape. We find that the photo-evaporative mass loss has a significant impact on the evolution of hot sub/super-Earths. We then derive the threshold planetary mass and radius below which the planet loses its water envelope completely as a function of the initial water content, and find that there are minimums of the threshold mass and radius. We constrain the domain in the parameter space of planetary mass, radius, and semimajor axis in which sub/super-Earths never retain water envelopes in 1-10 Gyr. This would provide an essential piece of information for understanding the origin of close-in low-mass planets. The current uncertainties in stellar XUV flux and its heating efficiency, however, prevent us from deriving robust conclusions. Nevertheless, it seems to be a robust conclusion that Kepler planet candidates contain a significant number of rocky sub/super-Earths.

  Jul. 2013, Astronomy & Astrophysics, 562, A80, English

  [Refereed]

  Scientific journal


• Multi-Color Transit Photometry of GJ 1214b through BJHKs-Bands and a Long-Term Monitoring of the Stellar Variability of GJ 1214

  Norio Narita, Akihiko Fukui, Masahiro Ikoma, Yasunori Hori, Kenji Kurosaki, Yui Kawashima, Takahiro Nagayama, Masahiro Onitsuka, Amnart Sukom, Yasushi Nakajima, Motohide Tamura, Daisuke Kuroda, Kenshi Yanagisawa, Teruyuki Hirano, Kiyoe Kawauchi, Masayuki Kuzuhara, Hiroshi Ohnuki, Takuya Suenaga, Yasuhiro H. Takahashi, Hideyuki Izumiura, Nobuyuki Kawai, Michitoshi Yoshida

  We present 5 new transit light curves of GJ 1214b taken in BJHKs-bands. Two transits were observed in B-band using the Suprime-Cam and the FOCAS instruments onboard the Subaru 8.2m telescope, and one transit was done in JHKs-bands simultaneously with the SIRIUS camera on the IRSF 1.4m telescope. MCMC analyses show that the planet-to-star radius ratios are, Rp/Rs = 0.11651 \pm 0.00065 (B-band, Subaru/Suprime-Cam), Rp/Rs = 0.11601 \pm 0.00117 (B-band, Subaru/FOCAS), Rp/Rs = 0.11654 \pm 0.00080 (J-band, IRSF/SIRIUS), Rp/Rs = 0.11550 ^{+0.00142}_{-0.00153} (H-band, IRSF/SIRIUS), and Rp/Rs = 0.11547 \pm 0.00127 (Ks-band, IRSF/SIRIUS). The Subaru Suprime-Cam transit photometry shows a possible spot-crossing feature. Comparisons of the new transit depths and those from previous studies with the theoretical models by Howe & Burrows (2012) suggest that the high molecular weight atmosphere (e.g., 1% H$_2$O + 99% N$_2$) models are most likely, however, the low molecular weight (hydrogen dominated) atmospheres with extensive clouds are still not excluded. We also report a long-term monitoring of the stellar brightness variability of GJ 1214 observed with the MITSuME 50cm telescope in g'-, Rc-, and Ic-bands simultaneously. The monitoring was conducted for 32 nights spanning 78 nights in 2012, and we find a periodic brightness variation with a period of Ps = 44.3 \pm 1.2 days and semi-amplitudes of 2.1% \pm 0.4% in g'-band, 0.56% \pm 0.08% in Rc-band, and 0.32% \pm 0.04% in Ic-band.

  May 2013, The Astrophysical Journal, 773(2) (2), 144, English

  [Refereed]

  Scientific journal


• Optical-to-Near-Infrared Simultaneous Observations for the Hot Uranus GJ3470b: A Hint for Cloud-free Atmosphere

  Akihiko Fukui, Norio Narita, Kenji Kurosaki, Masahiro Ikoma, Kenshi Yanagisawa, Daisuke Kuroda, Yasuhiro Shimizu, Yasuhiro H. Takahashi, Hiroshi Ohnuki, Masahiro Onitsuka, Teruyuki Hirano, Takuya Suenaga, Kiyoe Kawauchi, Shogo Nagayama, Kouji Ohta, Michitoshi Yoshida, Nobuyuki Kawai, Hideyuki Izumiura

  We present optical (g', R_c, and I_c) to near-infrared (J) simultaneous photometric observations for a primary transit of GJ3470b, a Uranus-mass transiting planet around a nearby M dwarf, by using the 50-cm MITSuME telescope and the 188-cm telescope, both at Okayama Astrophysical Observatory. From these data, we derive the planetary mass, radius, and density as 14.1 \pm 1.3 M_earth, 4.32^{+0.21}_{-0.10} R_earth, and 0.94 \pm 0.12 g cm^{-3}, respectively, thus confirming the low density that was reported by Demory et al. based on the Spitzer/IRAC 4.5-micron photometry (0.72^{+0.13}_{-0.12} g cm^{-3}). Although the planetary radius is about 10% smaller than that reported by Demory et al., this difference does not alter their conclusion that the planet possesses a hydrogen-rich envelope whose mass is approximately 10% of the planetary total mass. On the other hand, we find that the planet-to-star radius ratio (R_p/R_s) in the J band (0.07577^{+0.00072}_{-0.00075}) is smaller than that in the I_c (0.0802 \pm 0.0013) and 4.5-micron (0.07806^{+0.00052}_{-0.00054}) bands by 5.9% \pm 2.0% and 3.0% \pm 1.2%, respectively. A plausible explanation for the differences is that the planetary atmospheric opacity varies with wavelength due to absorption and/or scattering by atmospheric molecules. Although the significance of the observed R_p/R_s variations is low, if confirmed, this fact would suggest that GJ3470b does not have a thick cloud layer in the atmosphere. This property would offer a wealth of opportunity for future transmission-spectroscopic observations of this planet to search for certain molecular features, such as H2O, CH4, and CO, without being prevented by clouds.

  Feb. 2013, The Astrophysical Journal, 770(2) (2), 95, English

  [Refereed]

  Scientific journal

• 日本地球惑星科学連合

  - Present


• 日本天文学会

  - Present


• 日本惑星科学会

  - Present

• 天体衝突が引き起こす衛星形成過程および衝突後の惑星進化過程の解明

  黒崎 健二

  日本学術振興会, 科学研究費助成事業, 基盤研究(C), 神戸大学, Apr. 2024 - Mar. 2027, Principal investigator


• 大規模クレーター形成に伴う地下氷の融解と地下ハビタブルゾーンの生成可能性

  保井 みなみ, 黒崎 健二

  日本学術振興会, 科学研究費助成事業, 基盤研究(B), 神戸大学, Apr. 2023 - Mar. 2026, Coinvestigator


• A study of the late stege planetary formation by high-resolution numerical simulation of the giant impact

  黒崎 健二

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for JSPS Fellows, Grant-in-Aid for JSPS Fellows, Nagoya University, 24 Apr. 2020 - 31 Mar. 2023

  当該年度では惑星形成後期過程において発生することが期待される巨大衝突現象の数値シミュレーションを行った．原始惑星系円盤の中で形成する原始惑星は天体自身の重力により必然的に周囲の円盤から大気を獲得することが見込まれる．したがって，惑星形成後期過程においては，大気を持った天体同士が衝突合体を繰り返すというプロセスを経て，現在観測される惑星系が完成する．本研究計画では，原始惑星系円盤内で形成した大気を持つ惑星が衝突合体を経ることで，惑星大気がどのような変化をたどるかを議論するものである．当該年度では，様々な質量・大気量を持つ天体を用意し，それらが衝突合体を起こす様子を粒子法を用いた数値流体シミュレーションを行った．大規模な衝突合体に伴って，天体が持つ大気の大部分が失われ，大気をほとんど持たない岩石天体が形成する可能性が高いことを示し，さらに衝突によって失われる大気量にも，衝突エネルギーに比例した一定の法則があることがわかった．当該年度では，まず天体同士の正面衝突に限定して議論を構築し，衝突に伴うエネルギー分配を理解することが，天体衝突現象の理解に重要であることを示した．さらに天体衝突現象に伴う大気流出量の影響から，惑星形成理論への制約をつなげることを示唆できた．すなわち，大気を多く持った惑星は原始惑星系円盤内で形成し，その後に巨大衝突を経験せずに形成しなければならないということである．このような発見は今後惑星形成理論を組み立てる上で本質的となる．


• Long term atmospheric stability after the giant impact event

  黒崎 健二

  Japan Society for the Promotion of Science, Grants-in-Aid for Scientific Research Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Grant-in-Aid for Scientific Research on Innovative Areas (Research in a proposed research area), Nagoya University, Apr. 2021 - Mar. 2023, Principal investigator


• 内部組成勾配を考慮したスーパーアースの内部構造と熱進化の理論的研究

  黒﨑 健二

  日本学術振興会, 科学研究費助成事業 特別研究員奨励費, 特別研究員奨励費, 東京大学, Apr. 2014 - Mar. 2016, Principal investigator

  採用第２年度目では，惑星大気中における組成の勾配，特に惑星大気における凝結を考慮した際，巨大氷惑星がどのような内部構造・熱進化をたどるかを検討した．本年度では，惑星大気構造および惑星内部構造計算手法の改良を行い，系外惑星だけでなく，太陽系内惑星にも応用可能なモデルを作成した．本研究では大気中の凝縮による影響を惑星熱進化モデルに取り入れ，太陽系内の巨大氷惑星の熱進化計算に応用した．計算の結果，凝縮物の効果を考慮することで，大気中の温度が上昇し，熱進化の時間スケールが短縮されることがわかった．これによって，惑星の熱進化による冷却が促進される効果が確認され，天王星の放射強度を説明可能となった．私が行った計算の結果では，天王星大気中に多量の氷成分の存在が示唆されたため，天王星は形成初期に大気中に多量な氷成分を持つようなイベント，例えば巨大衝突のような大規模なイベントを経験していたことを示唆している．このような巨大衝突イベントがあったことは，天王星に見られる他の要素（自転軸傾斜角，衛星の軌道面）を説明する上でも整合性がとれている． これらの研究成果は，今後惑星形成理論，とくに観測から形成直後の状態を制約するための手法を確立することができた．今後は形成直後に過程した状態が，実際にどのように起こるのか，隕石や大気組成など他の物質化学的な状態にどのような影響を残すのかを多角的に議論する必要がある．本研究の成果は，今後系外惑星および太陽系内惑星の起源と観測を結びつける上で重要な役割を果たし，これらの研究を軸にして惑星形成論を検証する枠組みを提案していきたいと考えている．