Ice Lines in Circumbinary Protoplanetary Disks

Abstract

I examine the position of the ice line in circumbinary disks heated by steady mass accretion and stellar irradiation and compare with the critical semi-major axis, interior to which planetary orbits are unstable. There is a critical binary separation, dependent on the binary parameters and disk properties, for which the ice line lies within the critical semi-major axis for a given binary system. For an equal mass binary comprised of 1 M${}_{\odot }$ components, this critical separation is $\approx 1.04$AU, and scales weakly with mass accretion rate and Rosseland mean opacity ($\propto [\dot{M}{\kappa }_R{]}^{2/9}$). Assuming a steady mass accretion rate of $\dot{M}\sim 10^{-8}{\mathrm{M}}_{\odot }\mathrm{y}{\mathrm{r}}^{-1}$ and a Rosseland mean opacity of ${\kappa }_R\sim 1\mathrm{c}{\mathrm{m}}^2{\mathrm{g}}^{-1}$, I show that $\gtrsim 80$ of all binary systems with total masses $M_{\mathrm{tot}}\lesssim 4.0M_{\odot }$ have ice lines that lie interior to the critical semi-major axis. This suggests that rocky planets should not form in these systems, a prediction which can be tested by looking for planets around binaries with separations larger than the critical separation with \emph{Kepler} (difficult) and with microlensing.

5 pages, 3 figures. Submitted to ApJL

References in corpus (12)

• A Survey of Stellar Families: Multiplicity of Solar-Type Stars
• Kepler-16: A Transiting Circumbinary Planet
• Planet formation around stars of various masses: The snow line and the frequency of giant planets
• The Transiting Circumbinary Planets Kepler-34 and Kepler-35
• Kepler-47: A Transiting Circumbinary Multi-Planet System
• Analytical protostellar disk models 1: the effect of internal dissipation and surface irradiation on the structure of disks and the location of the snow line around Sun-like stars
• On the Location of the Snow Line in a Protoplanetary Disk
• The Disk Around CoKu Tau/4: Circumbinary, not Transitional
• The Neptune-Sized Circumbinary Planet Kepler-38b
• Formation and Evolution of Planetary Systems: Upper Limits to the Gas Mass in Disks Around Sun-like Stars
• On the migration of protoplanets embedded in circumbinary disks
• Microlensing Search for Planets with Two Simultaneously Rising Suns

Cited by in corpus (7)

• Kepler-413b: a slightly misaligned, Neptune-size transiting circumbinary planet
• Formation of polar terrestrial circumbinary planets
• Circumbinary Habitability Niches
• Terrestrial planet formation in a circumbinary disc around a coplanar binary
• Tatooine Nurseries: Structure and Evolution of Circumbinary Protoplanetary Disks
• On the location of the ice line in circumbinary discs
• Infrared Variability from Circumbinary Disc Temperature Modulations