Insights into Planet Formation from Debris Disks

Wyatt, M. C.; Jackson, Alan P.

doi:10.1007/s11214-016-0248-1

Cited by 50 publications

(23 citation statements)

References 160 publications

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“…Significant brightening and variability observed in emission from debris disks have been suggested as evidence of collisions between large bodies in the era of small planet formation (Meng et al 2014). Simulations also indicate that giant impacts occur in the later stages of planet formation (see Wyatt & Jackson 2016;Quintana et al 2016, and references therein), although high impact velocities and impact angles between 0-30 • are required to produce the maximally effective collisions for stripping mantles (Agnor & Asphaug 2004;Asphaug et al 2006;Asphaug 2009;Marcus et al 2009). Specifically, to reproduce the current mass and high iron mass fraction of planet b, Marcus et al (2010) predict that a collision with an object of similar mass at ∼60-80 km s −1 is required.…”

Section: High Density Of Gj 9827bmentioning

confidence: 99%

Magellan/PFS Radial Velocities of GJ 9827, a Late K dwarf at 30 pc with Three Transiting Super-Earths

Teske

Wang

Wolfgang

et al. 2018

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The Kepler mission showed us that planets with sizes between that of Earth and Neptune appear to be the most common type in our Galaxy. These "super-Earths" continue to be of great interest for exoplanet formation, evolution, and composition studies. However, the number of super-Earths with well-constrained mass and radius measurements remains small (40 planets with σ mass < 25%), due in part to the faintness of their host stars causing ground-based mass measurements to be challenging. Recently, three transiting super-Earth planets were detected by the K2 mission around the nearby star GJ 9827/HIP 115752, at only 30 pc away. The radii of the planets span the "radius gap" detected by , and all orbit within ∼6.5 days, easing follow-up observations. Here we report radial velocity (RV) observations of GJ 9827, taken between 2010 and 2016 with the Planet Finder Spectrograph on the Magellan II Telescope. We employ two different RV analysis packages, SYSTEMIC and RADVEL, to derive masses and thus densities of the GJ 9827 planets. We also test a Gaussian Process regression analysis, but find the correlated stellar noise is not well constrained by the PFS data, and that the GP tends to over fit the RV semi-amplitudes arXiv:1711.01359v4 [astro-ph.EP] 28 Feb 2018 2 TESKE ET AL. resulting in a lower K value. Our RV observations are not able to place strong mass constraints on the two outer planets (c & d) but do indicate that planet b, at 1.64 R ⊕ and ∼ 8 M ⊕ , is one of the most massive (and dense) super-Earth planets detected to date.

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Section: High Density Of Gj 9827bmentioning

confidence: 99%

Magellan/PFS Radial Velocities of GJ 9827, a Late K dwarf at 30 pc with Three Transiting Super-Earths

Teske

Wang

Wolfgang

et al. 2018

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“…Another plausible explanation could be dust released by a recent giant impact in the system. Even if this hypothesis is quite speculative, it is worth noting that the age of the host star is similar to the age of the Sun at the time of the Late Heavy Bombardment, and Wyatt & Jackson (2016) claim that observing the effects of giant impacts in systems hosting a debris disc is not unlikely. However, even after accounting for the associated flux loss, the radius associated with the best reddened fit is still too small (<1.3 R Jup ) to be consistent with the 1.6 R Jup that the Baraffe et al (2003) evolutionary models associate with a 1600 K, log g = 4.0, atmosphere of 9-10 M Jup object aged 10 Myr.…”

Section: Atmosphere Models Artificially Reddenedmentioning

confidence: 99%

In-depth study of moderately young but extremely red, very dusty substellar companion HD 206893B

Delorme

Schmidt

Bonnefoy

et al. 2017

A&A

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Context. The substellar companion HD 206893b has recently been discovered by direct imaging of its disc-bearing host star with the Spectro-Polarimetric High-contrast Exoplanet REsearch (SPHERE) instrument. Aims. We investigate the atypical properties of the companion, which has the reddest near-infrared colours among all known substellar objects, either orbiting a star or isolated, and we provide a comprehensive characterisation of the host star-disc-companion system. Methods. We conducted a follow-up of the companion with adaptive optics imaging and spectro-imaging with SPHERE, and a multi-instrument follow-up of its host star. We obtain a R = 30 spectrum from 0.95 to 1.64 μm of the companion and additional photometry at 2.11 and 2.25 μm. We carried out extensive atmosphere model fitting for the companions and the host star in order to derive their age, mass, and metallicity. Results. We found no additional companion in the system in spite of exquisite observing conditions resulting in sensitivity to 6 MJup (2 MJup) at 0.5′′ for an age of 300 Myr (50 Myr). We detect orbital motion over more than one year and characterise the possible Keplerian orbits. We constrain the age of the system to a minimum of 50 Myr and a maximum of 700 Myr, and determine that the host-star metallicity is nearly solar. The comparison of the companion spectrum and photometry to model atmospheres indicates that the companion is an extremely dusty late L dwarf, with an intermediate gravity (log g ~ 4.5–5.0) which is compatible with the independent age estimate of the system. Conclusions. Though our best fit corresponds to a brown dwarf of 15–30 MJup aged 100–300 Myr, our analysis is also compatible with a range of masses and ages going from a 50 Myr 12 MJup planetary-mass object to a 50 MJup Hyades-age brown dwarf. Even though this companion is extremely red, we note that it is more probable that it has an intermediate gravity rather than the very low gravity that is often associated with very red L dwarfs. We also find that the detected companion cannot shape the observed outer debris disc, hinting that one or several additional planetary mass objects in the system might be necessary to explain the position of the disc inner edge.

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“…Two stars have 24 m-only excesses, and neither showed evidence of ongoing accretion on to their stars. The SED fitted temperatures puts the dust in these systems within 1 au, which could be from a close-in asteroid belt (Wyatt 2008;Chen et al 2009;Morales et al 2009;Kennedy & Wyatt 2014), or dust created during collisions between forming planets (e.g., the shake-down of Kepler planetary systems Kenyon & Bromley 2004;Genda et al 2015;Wyatt & Jackson 2016;Su et al 2020). We therefore place these in a separate category to the other class III YSOs, since while the mid-IR excess could be an indicator that planetesimal formation has taken place (and/or that planet formation is ongoing), it is not clear that this has taken place beyond a few au (i.e., at debris disk radii) given the limits set by the non-detection of sub-mm dust.…”

Section: Hot Dust From Asteroid Belts or Planet Formation: MV Lup And Cd-31 12522mentioning

confidence: 99%

ALMA survey of Lupus class III stars: Early planetesimal belt formation and rapid disc dispersal

Lovell

Wyatt

Ansdell

et al. 2020

Monthly Notices of the Royal Astronomical Society

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Class III stars are those in star forming regions without large non-photospheric infrared emission, suggesting recent dispersal of their protoplanetary disks. We observed 30 class III stars in the 1-3 Myr Lupus region with ALMA at ∼856μm, resulting in 4 detections that we attribute to circumstellar dust. Inferred dust masses are 0.036 − 0.093M⊕, ∼1 order of magnitude lower than any previous measurements; one disk is resolved with radius ∼80 au. Two class II sources in the field of view were also detected, and 11 other sources, consistent with sub-mm galaxy number counts. Stacking non-detections yields a marginal detection with mean dust mass ∼0.0048M⊕. We searched for gas emission from the CO J=3-2 line, and present its detection to NO Lup inferring a gas mass (4.9 ± 1.1) × 10−5 M⊕ and gas-to-dust ratio 1.0 ± 0.4. Combining our survey with class II sources shows a gap in the disk mass distribution from 0.09 − 2M⊕ for >0.7M⊙ Lupus stars, evidence of rapid dispersal of mm-sized dust from protoplanetary disks. The class III disk mass distribution is consistent with a population model of planetesimal belts that go on to replenish the debris disks seen around main sequence stars. This suggests that planetesimal belt formation does not require long-lived protoplanetary disks, i.e., planetesimals form within ∼2 Myr. While all 4 class III disks are consistent with collisional replenishment, for two the gas and/or mid-IR emission could indicate primordial circumstellar material in the final stages of protoplanetary disk dispersal. Two class III stars without sub-mm detections exhibit hot emission that could arise from ongoing planet formation processes inside ∼1 au.

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Insights into Planet Formation from Debris Disks

Cited by 50 publications

References 160 publications

Magellan/PFS Radial Velocities of GJ 9827, a Late K dwarf at 30 pc with Three Transiting Super-Earths

Magellan/PFS Radial Velocities of GJ 9827, a Late K dwarf at 30 pc with Three Transiting Super-Earths

In-depth study of moderately young but extremely red, very dusty substellar companion HD 206893B

ALMA survey of Lupus class III stars: Early planetesimal belt formation and rapid disc dispersal

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