Large impacts around a solar-analog star in the era of terrestrial planet formation

Meng, Huan; Su, K. Y. L.; Rieke, G. H.; Stevenson, D. J.; Plavchan, Peter; Rujopakarn, W.; Lisse, C. M.; Poshyachinda, S.; Reichart, D.

doi:10.1126/science.1255153

Cited by 95 publications

(66 citation statements)

References 44 publications

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“…The vertical dashed lines show the level of variability for sources discussed in Sect. 6.3 Meng et al 2014Meng et al , 2015 we estimate the fraction of Sun-like stars in Upper Sco with detectable 12 µm excesses is ∼ 10 %, in broad agreement with the findings of , particularly if one considers that the fraction is likely to decrease over the 10-120 Myr age range (and noting that some of the Upper Sco excesses are from protoplanetary disks).…”

Section: Photometric Fluxessupporting

confidence: 87%

“…Later observations showed that the near-IR (3-5 µm) emission to this star underwent a substantial brightening followed by decay on a year timescale, with quasi-periodic modulations (with period ∼ 30 days) in the disk flux (Meng et al 2014). This was interpreted as the result of a giant collision in which silicate vapour is created out of which small particles condense and subsequently collisionally deplete.…”

Section: Time Variabilitymentioning

confidence: 92%

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Insights into Planet Formation from Debris Disks

Wyatt

Jackson

2016

Space Sci Rev

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Giant impacts refer to collisions between two objects each of which is massive enough to be considered at least a planetary embryo. The putative collision suffered by the proto-Earth that created the Moon is a prime example, though most Solar System bodies bear signatures of such collisions. Current planet formation models predict that an epoch of giant impacts may be inevitable, and observations of debris around other stars are providing mounting evidence that giant impacts feature in the evolution of many planetary systems. This chapter reviews giant impacts, focussing on what we can learn about planet formation by studying debris around other stars. Giant impact debris evolves through mutual collisions and dynamical interactions with planets. General aspects of this evolution are outlined, noting the importance of the collision-point geometry. The detectability of the debris is discussed using the example of the Moon-forming impact. Such debris could be detectable around another star up to 10 Myr post-impact, but model uncertainties could reduce detectability to a few 100 yr window. Nevertheless the 3 % of young stars with debris at levels expected during terrestrial planet formation provide valuable constraints on formation models; implications for super-Earth formation are also discussed. Variability recently observed in some bright disks promises to illuminate the evolution during the earliest phases when vapour condensates may be optically thick and acutely affected by the collision-point geometry. The outer reaches of planetary systems may also exhibit signatures of giant impacts, such as the clumpy debris structures seen around some stars.

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Section: Photometric Fluxessupporting

confidence: 87%

Section: Time Variabilitymentioning

confidence: 92%

Insights into Planet Formation from Debris Disks

Wyatt

Jackson

2016

Space Sci Rev

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“…Protoplanetary disks reveal ongoing chemical and spatial processes related to the earliest stages of planet formation, and especially volatile grain chemistry and dust trapping (Pontoppidan et al 2014;van der Marel et al 2016) prior to and possibly during their incorporation into large bodies. Young and mature main-sequence stars reveal systems of fullyfledged planets, their planetesimal belt leftovers, and (giant impact) collisional by-products (Meng et al 2014;MacGregor et al 2017;Chauvin et al 2017). These planetary systems yield final architectures and assemblies, where the physical and chemical processes associated with planet formation are essentially exhausted and thus must be inferred via modeling.…”

Section: Introductionmentioning

confidence: 99%

Magnetism, X-rays and accretion rates in WD 1145+017 and other polluted white dwarf systems

Farihi

Fossati

Wheatley

et al. 2017

Monthly Notices of the Royal Astronomical Society

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This paper reports circular spectropolarimetry and X-ray observations of several polluted white dwarfs including WD 1145+017, with the aim to constrain the behavior of disk material and instantaneous accretion rates in these evolved planetary systems. Two stars with previously observed Zeeman splitting, WD 0322-019 and WD 2105-820, are detected above 5σ and B z > 1 kG, while WD 1145+017, WD 1929+011, and WD 2326+049 yield (null) detections below this minimum level of confidence. For these latter three stars, high-resolution spectra and atmospheric modeling are used to obtain limits on magnetic field strengths via the absence of Zeeman splitting, finding B * < 20 kG based on data with resolving power R ≈ 40 000. An analytical framework is presented for bulk Earth composition material falling onto the magnetic polar regions of white dwarfs, where X-rays and cyclotron radiation may contribute to accretion luminosity. This analysis is applied to X-ray data for WD 1145+017, WD 1729+371, and WD 2326+049, and the upper bound count rates are modeled with spectra for a range of plasma kT = 1 − 10 keV in both the magnetic and non-magnetic accretion regimes. The results for all three stars are consistent with a typical dusty white dwarf in a steady state at 10 8 − 10 9 g s −1 . In particular, the non-magnetic limits for WD 1145+017 are found to be well below previous estimates of up to 10 , thus suggesting the star-disk system may be average in its evolutionary state, and only special in viewing geometry.

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“…Peculiar light curves and slow trends are common among young stellar objects (YSOs) (Rebull et al 2014;Stauffer et al 2015;Ansdell et al 2016), and may result from the obscuration by dust generated by disintegrating planets (e.g., Rappaport et al 2012Rappaport et al , 2014Sanchis-Ojeda et al 2015) or planetesimal/planet collisions (e.g., Meng et al 2014Meng et al , 2015 if viewed edge-on (Bozhinova et al 2016). However, KIC 8462852 does not appear to fit into either scenario.…”

Section: Introductionmentioning

confidence: 99%

Extinction and the Dimming of KIC 8462852

Meng

Rieke

Dubois³

et al. 2017

ApJ

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To test alternative hypotheses for the behavior of KIC 8462852, we obtained measurements of the star over a wide wavelength range from the UV to the mid-infrared from October 2015 through December 2016, using Swift, Spitzer and at AstroLAB IRIS. The star faded in a manner similar to the longterm fading seen in Kepler data about 1400 days previously. The dimming rate for the entire period reported is 22.1 ± 9.7 milli-mag yr −1 in the Swift wavebands, with amounts of 21.0 ± 4.5 mmag in the groundbased B measurements, 14.0 ± 4.5 mmag in V , and 13.0 ± 4.5 in R, and a rate of 5.0 ± 1.2 mmag yr −1 averaged over the two warm Spitzer bands. Although the dimming is small, it is seen at 3 σ by three different observatories operating from the UV to the IR. The presence of long-term secular dimming means that previous SED models of the star based on photometric measurements taken years apart may not be accurate. We find that stellar models with T ef f = 7000 -7100 K and A V ∼ 0.73 best fit the Swift data from UV to optical. These models also show no excess in the near-simultaneous Spitzer photometry at 3.6 and 4.5 µm, although a longer wavelength excess from a substantial debris disk is still possible (e.g., as around Fomalhaut). The wavelength dependence of the fading favors a relatively neutral color (i.e., R V 5, but not flat across all the bands) compared with the extinction law for the general ISM (R V = 3.1), suggesting that the dimming arises from circumstellar material.

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Large impacts around a solar-analog star in the era of terrestrial planet formation

Cited by 95 publications

References 44 publications

Insights into Planet Formation from Debris Disks

Insights into Planet Formation from Debris Disks

Magnetism, X-rays and accretion rates in WD 1145+017 and other polluted white dwarf systems

Extinction and the Dimming of KIC 8462852

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