What question did this study set out to answer?

To evaluate the physical viability of direct gravitational instability as a mechanism for giant planet formation by examining dynamical and radiative cooling constraints in protoplanetary disks.

January 31, 2005The Astrophysical JournalOpen Access

Can Giant Planets Form by Direct Gravitational Instability?

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Authors

RRRoman R. RafikovUniversity of Cambridge

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Implication

Theoretical analysis reveals stringent thermal and dynamical limits on protoplanetary disks, indicating direct gravitational instability rarely forms typical giant planets.

Key Points

To evaluate the physical viability of direct gravitational instability as a mechanism for giant planet formation by examining dynamical and radiative cooling constraints in protoplanetary disks.
Applied combined dynamical stability and thermal cooling timescale constraints to determine conditions necessary for disk fragmentation into bound clumps.
Calculated required disk properties, including gas temperature, disk mass, and luminosity, at orbital radii of 10 AU and 100 AU under radiation transfer cooling.
Direct fragmentation at 10 AU requires extreme disk conditions, including gas temperatures exceeding 10³ K, a minimum disk mass of 0.7 M☉, and a luminosity of 40 L☉.
At larger separations (~100 AU), cooling constraints are relaxed, but the resulting bound fragments have masses of approximately 10 MJ, which are too massive to represent typical extrasolar giant planets.

Cite This Study

Roman R. Rafikov (2005) studied this question.

synapsesocial.com/papers/6a95cb8f8372d5bc84539459 https://doi.org/10.1086/428899

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January 31, 2005The Astrophysical JournalOpen Access

Can Giant Planets Form by Direct Gravitational Instability?

View Full Paper

Ask AI

Bookmark

Authors

RRRoman R. RafikovUniversity of Cambridge

Discussion

Member takes

Implication

Theoretical analysis reveals stringent thermal and dynamical limits on protoplanetary disks, indicating direct gravitational instability rarely forms typical giant planets.

Key Points

To evaluate the physical viability of direct gravitational instability as a mechanism for giant planet formation by examining dynamical and radiative cooling constraints in protoplanetary disks.
Applied combined dynamical stability and thermal cooling timescale constraints to determine conditions necessary for disk fragmentation into bound clumps.
Calculated required disk properties, including gas temperature, disk mass, and luminosity, at orbital radii of 10 AU and 100 AU under radiation transfer cooling.
Direct fragmentation at 10 AU requires extreme disk conditions, including gas temperatures exceeding 10³ K, a minimum disk mass of 0.7 M☉, and a luminosity of 40 L☉.
At larger separations (~100 AU), cooling constraints are relaxed, but the resulting bound fragments have masses of approximately 10 MJ, which are too massive to represent typical extrasolar giant planets.

Cite This Study

Roman R. Rafikov (2005) studied this question.

synapsesocial.com/papers/6a95cb8f8372d5bc84539459 https://doi.org/10.1086/428899

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