ALMA CONTINUUM OBSERVATIONS OF A 30 Myr OLD GASEOUS DEBRIS DISK AROUND HD 21997

Moór, A.; Juhász, A.; Kóspál, Á.; Ábrahám, P.; Apai, Dániel; Csengeri, T.; Grady, C. A.; Henning, Th.; Hughes, A. Meredith; Kiss, Cs.; Pascucci, Ilaria; Schmalzl, M.; Gabányi, K. É.

doi:10.1088/2041-8205/777/2/l25

Cited by 44 publications

(39 citation statements)

References 31 publications

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“…However we will briefly describe these features, as they could potentially be observed with a high resolution instrument such as ALMA (e.g. Moór et al 2013;Dent et al 2014) or the HST (e.g. Golimowski et al 2011).…”

Section: Disc Overdensitiesmentioning

confidence: 99%

Dynamical evolution of an eccentric planet and a less massive debris disc

Pearce

Wyatt

2014

Monthly Notices of the Royal Astronomical Society

102

147

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We investigate the interaction between an eccentric planet and a less massive external debris disc. This scenario could occur after planet-planet scattering or merging events. We characterise the evolution over a wide range of initial conditions, using a suite of n-body integrations combined with theory. Planets near the disc mid-plane remove the inner debris region, and surviving particles form an eccentric disc apsidally aligned with the planet. The inner disc edge is elliptical and lies just beyond the planet's orbit. Moderately inclined planets (i plt 20• for e plt = 0.8) may instead sculpt debris into a bell-shaped structure enveloping the planet's orbit. Finally some highly inclined planets (i plt ∼ 90• ) can maintain a disc orthogonal to the planet's plane. In all cases disc particles undergo rapid evolution, whilst the overall structures evolve more slowly. The shapes of these structures and their density profiles are characterised. The width of the chaotic zone around the planet's orbit is derived in the coplanar case using eccentric Hill radius arguments. This zone is cleared within approximately ten secular or diffusion times (whichever is longer), and debris assumes its final shape within a few secular times. We quantify the planet's migration and show it will almost always be small in this mass regime. Our results may be used to characterise unseen eccentric planets using observed debris features.

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Section: Disc Overdensitiesmentioning

confidence: 99%

Dynamical evolution of an eccentric planet and a less massive debris disc

Pearce

Wyatt

2014

Monthly Notices of the Royal Astronomical Society

102

147

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“…This surprising result indicates that TW Hydrae is an old PMS star containing a massive gas disc that is several times the minimum mass required to make all the planets in our solar system. Even more recently, Roberge et al (2013) and Moór et al (2013) reported the discoveries of a low-mass protoplanetary-like gaseous disc, together with debris discs, around the older PMS stars 49 Ceti and HD 95086, with ages ranging from 10 Myr to 30 Myr. All these results support a scenario in which old and evolved debris discs still host a significant amount of gas and confirm our results with completely independent measurements.…”

Section: Spectral Energy Distributionsmentioning

confidence: 99%

Mass accretion rates from multiband photometry in the Carina Nebula: the case of Trumpler 14

Beccari¹,

Marchi²,

Panagia³

et al. 2015

A&A

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We present a study of the mass accretion rates of pre-main sequence (PMS) stars in the cluster Trumpler 14 (Tr 14) in the Carina Nebula. Using optical multiband photometry we were able to identify 356 PMS stars showing Hα excess emission with equivalent width EW(Hα) > 20 Å. We interpret this observational feature as an indication that these objects are still actively accreting gas from their circumstellar medium. From a comparison of the HR diagram with PMS evolutionary models we derive ages and masses of the PMS stars. We find that most of the PMS objects are younger than 10 Myr with a median age of ∼3 Myr. Surprisingly, we also find that ∼20% of the mass accreting objects are older than 10 Myr. For each PMS star in Trumpler 14 we determine the mass accretion rate (Ṁ acc ) and discuss its dependence on mass and age. We finally combine the optical photometry with near-IR observations to build the spectral energy distribution (SED) for each PMS star in Tr 14. The analysis of the SEDs suggests the presence of transitional discs in which a large amount of gas is still present and sustains accretion onto the PMS object at ages older than 10 Myr. Our results, discussed in light of recent recent discoveries with Herschel of transitional discs containing a massive gas component around the relatively old PMS stars TW Hydrae, 49 Ceti, and HD 95086, support a new scenario n which old and evolved debris discs still host a significant amount of gas.

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“…This is supported by observations that planets are a common phenomenon in our galaxy, with an average of at least one planet per star (e.g., Cassan et al 2012) While it has been generally assumed that debris disks are devoid of molecular gas, detections of gas emission through millimeter-wavelength spectroscopy date back at least two decades (Zuckerman et al 1995;Dent et al 2005), and absorption line spectroscopy in edge-on debris disks has also identified the presence of a circumstellar gas component around a number of different stars (Crawford et al 1994;Roberge et al 2002;Chen & Jura 2003;Redfield 2007). Millimeterwavelength interferometry provided the first spatially resolved observations of the molecular gas emission in a debris disk (Hughes et al 2008a), and the improved sensitivity and angular resolution of the Atacama Large Millimeter/submillimeter Array (ALMA) has led to a resurgence of interest in these objects, resulting in spectacular gas and dust imaging of the recently discovered HD 21997 disk Moór et al 2013), the iconic β Pictoris disk (Dent et al 2014), and recently the first gas-bearing debris disk around a solar-type star (HD 181327; Marino et al 2016). Another object of interest has been the optically thin dust disk around the 5 Myr old Herbig Ae star HD 141569, whose classification as a transitional or debris disk has been an object of intense discussion in the literature: recent observations with the Submillimeter Array (SMA) and Combined Array for Research in Millimeter-wave Astronomy (CARMA) have spatially resolved the gas disk for the first time (Flaherty et al 2016), and ALMA observations probe the disk in greater detail (White et al 2016).…”

Section: Introductionmentioning

confidence: 99%

Radial Surface Density Profiles of Gas and Dust in the Debris Disk around 49 Ceti

Hughes

Lieman-Sifry

Flaherty

et al. 2017

ApJ

127

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We present ∼0 4 resolution images of CO(3-2) and associated continuum emission from the gas-bearing debris disk around the nearby A star 49 Ceti, observed with the Atacama Large Millimeter/Submillimeter Array (ALMA). We analyze the ALMA visibilities in tandem with the broadband spectral energy distribution to measure the radial surface density profiles of dust and gas emission from the system. The dust surface density decreases with radius between ∼100 and 310 au, with a marginally significant enhancement of surface density at a radius of ∼110 au. The SED requires an inner disk of small grains in addition to the outer disk of larger grains resolved by ALMA. The gas disk exhibits a surface density profile that increases with radius, contrary to most previous spatially resolved observations of circumstellar gas disks. While ∼80% of the CO flux is well described by an axisymmetric power-law disk in Keplerian rotation about the central star, residuals at ∼20% of the peak flux exhibit a departure from axisymmetry suggestive of spiral arms or a warp in the gas disk. The radial extent of the gas disk (∼220 au) is smaller than that of the dust disk (∼300 au), consistent with recent observations of other gasbearing debris disks. While there are so far only three broad debris disks with wellcharacterized radial dust profiles at millimeter wavelengths, 49 Ceti's disk shows a markedly different structure from two radially resolved gas-poor debris disks, implying that the physical processes generating and sculpting the gas and dust are fundamentally different.

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ALMA CONTINUUM OBSERVATIONS OF A 30 Myr OLD GASEOUS DEBRIS DISK AROUND HD 21997

Cited by 44 publications

References 31 publications

Dynamical evolution of an eccentric planet and a less massive debris disc

Dynamical evolution of an eccentric planet and a less massive debris disc

Mass accretion rates from multiband photometry in the Carina Nebula: the case of Trumpler 14

Radial Surface Density Profiles of Gas and Dust in the Debris Disk around 49 Ceti

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