The nature and origins of sub-Neptune size planets

Bean, Jacob L.; Raymond, Sean N.; Owen, James E.

doi:10.48550/arxiv.2010.11867

Cited by 3 publications

(4 citation statements)

References 169 publications

(220 reference statements)

Supporting

Mentioning

Contrasting

Order By: Relevance

“…The low-density nature of this hot mini-Neptune, combined with its bright host star, may enable transmission spectroscopy observations. Such measurement could test the hypotheses noted above, and search for a low-molecular weight primary atmosphere dominated by H-He, or a high molecular weight secondary atmosphere dominated by an overabundance of water vapour (Bean et al 2020). To test this, we computed the emission and transmission spectroscopy metrics from Kempton et al (2018).…”

Section: Potential For Future Observationsmentioning

confidence: 99%

A hot mini-Neptune in the radius valley orbiting solar analogue HD 110113

Osborn,

Armstrong,

Nielsen

et al. 2021

Preprint

View full text Add to dashboard Cite

We report the discovery of HD 110113 b (TOI-755.01), a transiting mini-Neptune exoplanet on a 2.5-day orbit around the solar-analogue HD 110113 (𝑇 eff = 5730K). Using TESS photometry and HARPS radial velocities gathered by the NCORES program, we find HD 110113 b has a radius of 2.05 ± 0.12 R ⊕ and a mass of 4.55 ± 0.62 M ⊕ . The resulting density of 2.90 +0.75 −0.59 g cm −3 is significantly lower than would be expected from a pure-rock world; therefore, HD 110113 b must be a mini-Neptune with a significant volatile atmosphere. The high incident flux places it within the so-called radius valley; however, HD 110113 b was able to hold onto a substantial (0.1-1%) H-He atmosphere over its ∼ 4Gyr lifetime. Through a novel simultaneous gaussian process fit to multiple activity indicators, we were also able to fit for the strong stellar rotation signal with period 20.8 ± 1.2 d from the RVs and confirm an additional non-transiting planet with a mass of 10.5 ± 1.2 M ⊕ and a period of 6.744 +0.008 −0.009 d.

show abstract

Section: Potential For Future Observationsmentioning

confidence: 99%

A hot mini-Neptune in the radius valley orbiting solar analogue HD 110113

Osborn,

Armstrong,

Nielsen

et al. 2021

Preprint

View full text Add to dashboard Cite

show abstract

“…For these reasons, we intentionally deviate from the original proposition Volk & Gladman (2015), and remind the reader that our work does not invoke super-Earth formation in the solar system, or exotic dynamical processes (e.g. : planetesimal shepherding) to generate our proposed initial conditions (see additional discussion in: Raymond et al 2016;Deienno et al 2020;Lenz et al 2020;Bean et al 2020).…”

Section: Motivationmentioning

confidence: 99%

“…Perhaps the disk conditions that gave rise to Mercury are still completely unknown (e.g. : Bean et al 2020), and the planets' origin will remain a mystery until future exploration of the surface shines light on the nature of the Mercury-forming planetesimals, and detailed disk observations and models conclusively reveal the elusive initial conditions that generate Mercury-like planets. It is also possible that the standard setups employed by contemporary formation studies are qualitatively correct (for example Lykawka & Ito 2019;Clement et al 2019b;Deienno et al 2019), and the apparent inability of such models to reproduce Mercury (figure 1) is the result of a flaw in methodology or approach (i.e.…”

Section: Motivationmentioning

confidence: 99%

Dynamical avenues for Mercury's origin I: The lone survivor of a primordial generation of short-period proto-planets

Clement,

Chambers,

Jackson

2021

Preprint

View full text Add to dashboard Cite

The absence of planets interior to Mercury continues to puzzle terrestrial planet formation models, particularly when contrasted with the relatively high derived occurrence rates of short-period planets around Sun-like stars. Recent work proposed that the majority of systems hosting hot super-Earths attain their orbital architectures through an epoch of dynamical instability after forming in quasistable, tightly packed configurations. Isotopic evidence seems to suggest that the formation of objects in the super-Earth mass regime is unlikely to have occurred in the solar system as the terrestrialforming disk is thought to have been significantly mass-deprived starting around 2 Myr after CAI; a consequence of either Jupiter's growth or an intrinsic disk feature. Nevertheless, terrestrial planet formation models and high-resolution investigations of planetesimal dynamics in the gas disk phase occasionally find that quasi-stable proto-planets with masses comparable to that of Mars emerge in the vicinity of Mercury's modern orbit. In this paper, we investigate whether it is possible for a primordial configuration of such objects to be cataclysmically destroyed in a manner that leaves Mercury behind as the sole survivor without disturbing the other terrestrial worlds. We use numerical simulations to show that this scenario is plausible. In many cases, the surviving Mercury analog experiences a series of erosive impacts; thereby boosting its Fe/Si ratio. A caveat of our proposed genesis scenario for Mercury is that Venus typically experiences at least one late giant impact.

show abstract

“…Volk & Gladman (2015) suggested that a system of tightly-packed planets might have existed in the young solar system (similar to, for example, Kepler-11 or TRAPPIST-1: Lissauer et al 2013;Gillon et al 2017) and were eventually lost as a result of having formed in a quasi-stable configuration (Izidoro et al 2017). While connecting the solar system to the Kepler catalog in this manner is compelling, it is unclear how the modern terrestrial planets might have survived such a scenario (see Raymond et al 2016;Clement et al 2019a;Lenz et al 2020;Bean et al 2020, for critiques of this hypothesis). Additionally, Raymond et al (2016) proposed that the truncated initial conditions often assumed in the literature (i.e.…”

Section: Introductionmentioning

confidence: 99%

Dynamical avenues for Mercury's origin II: in-situ formation in the inner terrestrial disk

Clement,

Chambers

2021

Preprint

View full text Add to dashboard Cite

Modern terrestrial planet formation models are highly successful at consistently generating planets with masses and orbits analogous to those of Earth and Venus. In stark contrast to classic theoretical predictions and inferred demographics of multi-planet systems of rocky exoplanets, the mass ( 10) and orbital period ( 2) ratios between Venus and Earth and the neighboring Mercury and Mars are not common outcomes in numerically generated systems. While viable solutions to the small-Mars problem are abundant in the literature, Mercury's peculiar origin remains rather mysterious. In this paper, we investigate the possibility that Mercury formed in a mass-depleted, inner region of the terrestrial disk (a < 0.5 au). This regime is often neglected in terrestrial planet formation models because of the high computational cost of resolving hundreds of short-period objects over ∼100 Myr timescales. By testing multiple disk profiles and mass distributions, we identify several promising sets of initial conditions that lead to remarkably successful analog systems. In particular, our most successful simulations consider moderate total masses of Mercury-forming material (0.1-0.25 Earth masses). While larger initial masses tend to yield disproportionate Mercury analogs, smaller values often inhibit the planets' formation as the entire region of material is easily accreted by Venus. Additionally, we find that shallow surface density profiles and larger inventories of small planetesimals moderately improve the likelihood of adequately reproducing Mercury.

show abstract

The nature and origins of sub-Neptune size planets

Cited by 3 publications

References 169 publications

A hot mini-Neptune in the radius valley orbiting solar analogue HD 110113

A hot mini-Neptune in the radius valley orbiting solar analogue HD 110113

Dynamical avenues for Mercury's origin I: The lone survivor of a primordial generation of short-period proto-planets

Dynamical avenues for Mercury's origin II: in-situ formation in the inner terrestrial disk

Contact Info

Product

Resources

About