Formation of Massive Rocky Exomoons by Giant Impact

Barr, A. C.; Syal, Megan Bruck

doi:10.1093/mnras/stx078

Cited by 9 publications

(8 citation statements)

References 54 publications

Supporting

Mentioning

Contrasting

Order By: Relevance

“…Figure 2 shows the disk mass M D and disk angular momentum L D as a function of the total mass M T for rocky and icy planets. The colors represent γ , and the dashed lines represent analytical estimates of the disk mass 25 . Generally, the disk mass agrees with the analytical model, especially at small γ .…”

Section: Resultsmentioning

confidence: 99%

See 1 more Smart Citation

Large planets may not form fractionally large moons

et al. 2022

View full text Add to dashboard Cite

One of the unique aspects of Earth is that it has a fractionally large Moon, which is thought to have formed from a Moon-forming disk generated by a giant impact. The Moon stabilizes the Earth’s spin axis at least by several degrees and contributes to Earth’s stable climate. Given that impacts are common during planet formation, exomoons, which are moons around planets in extrasolar systems, should be common as well, but no exomoon has been confirmed. Here we propose that an initially vapor-rich moon-forming disk is not capable of forming a moon that is large with respect to the size of the planet because growing moonlets, which are building blocks of a moon, experience strong gas drag and quickly fall toward the planet. Our impact simulations show that terrestrial and icy planets that are larger than ~1.3−1.6R⊕ produce entirely vapor disks, which fail to form a fractionally large moon. This indicates that (1) our model supports the Moon-formation models that produce vapor-poor disks and (2) rocky and icy exoplanets whose radii are smaller than ~1.6R⊕ are ideal candidates for hosting fractionally large exomoons.

show abstract

Section: Resultsmentioning

confidence: 99%

“…The colors represent the values of γ . The dashed lines represent the disk mass estimate from previous work assuming a rocky composition 25 . c , d The disk angular momentum L D normalized by the total angular momentum for rocky and icy planets L T , respectively.…”

Section: Resultsmentioning

confidence: 99%

Large planets may not form fractionally large moons

et al. 2022

View full text Add to dashboard Cite

show abstract

“…The very large cooling timescales (on the order of 10 5 − 10 6 yr) lead to the possibility of discovering tens of such planets in future surveys [28]. It has recently been suggested [72] that even gas giant planets may form visible massive, rocky exomoons as a result of giant impacts.…”

Section: The Typical Compositions Of Steam Atmospheres Have Been Consmentioning

confidence: 99%

Laboratory spectra of hot molecules: Data needs for hot super-Earth exoplanets

Tennyson

Yurchenko

2017

Molecular Astrophysics

View full text Add to dashboard Cite

The majority of stars are now thought to support exoplanets. Many of those exoplanets discovered thus far are categorized as rocky objects with an atmosphere. Most of these objects are however hot due to their short orbital period. Models suggest that water is the dominant species in their atmospheres. The hot temperatures are expected to turn these atmospheres into a (high pressure) steam bath containing remains of melted rock. The spectroscopy of these hot rocky objects will be very different from that of cooler objects or hot gas giants. Molecules suggested to be important for the spectroscopy of these objects are reviewed together with the current status of the corresponding spectroscopic data. Perspectives of building a comprehensive database of linelist/cross sections applicable for atmospheric models of rocky super-Earths as part of the ExoMol project are discussed.The quantum-mechanical approaches used in linelist productions and their challenges are summarized. ), key hot exoplanets with masses and radii in the rocky-planet range includeCoRoT-7b, Kepler-10b, Kepler-78b, Kepler-97b, Kepler-99b, Kepler-102b, Kepler-93b being slightly cooler than 1673 K [21,22,30,31,32,33,34,35,36] Most of the rocky exoplanets that have so far been studied are characterized by the high temperature of their atmospheres, e.g., about 1500 K in Kepler-36b and Kepler-93b, 2474 ± 71 K in CoRoT-7b [37], 2360 ± 300 K in 55 Cnc

show abstract

“…Most simulation studies of giant impacts have focused on the collisional phase space conductive to the formation of Solar system planets and satellites (Barr 2016). Despite an extensive collision simulation literature, there have only been a few studies that investigated hydrodynamical giant impact simulations relevant to exoplanets that are more massive than the Earth (Genda & Abe 2003;Marcus et al 2010a,b;Liu et al 2015;Inamdar & Schlichting 2015, 2016Barr & Bruck Syal 2017;Biersteker & Schlichting 2019). In particular, only Barr & Bruck Syal (2017) (hereafter BB17) focus on the formation of exosolar satellites (or rather the discs from which they accreted), while all the rest examine the effects on the exoplanets themselves.…”

Section: Collisional Formation Of Exomoonsmentioning

confidence: 99%

Collisional formation of massive exomoons of superterrestrial exoplanets

Malamud

Perets

Schäfer

et al. 2020

Monthly Notices of the Royal Astronomical Society

View full text Add to dashboard Cite

Exomoons orbiting terrestrial or super-terrestrial exoplanets have not yet been discovered; their possible existence and properties are therefore still an unresolved question. Here we explore the collisional formation of exomoons through giant planetary impacts. We make use of smooth particle hydrodynamical (SPH) collision simulations and survey a large phase-space of terrestrial/superterrestrial planetary collisions. We characterize the properties of such collisions, finding one rare case in which an exomoon forms through a graze & capture scenario, in addition to a few graze & merge or hit & run scenarios. Typically however, our collisions form massive circumplanetary discs, for which we use followup N-body simulations in order to derive lower-limit mass estimates for the ensuing exomoons. We investigate the mass, long-term tidal-stability, composition and origin of material in both the discs and the exomoons. Our giant-impact models often generate relatively iron-rich moons, that form beyond the synchronous radius of the planet, and would thus tidally evolve outward with stable orbits, rather than be destroyed. Our results suggest that it is extremely difficult to collisionally form currently-detectable exomoons orbiting super-terrestrial planets, through single giant impacts. It might be possible to form massive, detectable exomoons through several mergers of smaller exomoons, formed by multiple impacts, however more studies are required in order to reach a conclusion. Given the current observational initiatives, the search should focus primarily on more massive planet categories. However, about a quarter of the exomoons predicted by our models are approximately Mercury-mass or more, and are much more likely to be detectable given a factor 2 improvement in the detection capability of future instruments, providing further motivation for their development.

show abstract

Formation of Massive Rocky Exomoons by Giant Impact

Cited by 9 publications

References 54 publications

Large planets may not form fractionally large moons

Large planets may not form fractionally large moons

Laboratory spectra of hot molecules: Data needs for hot super-Earth exoplanets

Collisional formation of massive exomoons of superterrestrial exoplanets

Contact Info

Product

Resources

About