No Clear, Direct Evidence for Multiple Protoplanets Orbiting LkCa 15: LkCa 15 bcd are Likely Inner Disk Signals

Currie, Thayne; Marois, Christian; Cieza, Lucas A.; Mulders, Gijs D.; Lawson, Kellen; Cáceres, C.; Rodriguez-Ruiz, Dary; Wisniewski, John P.; Guyon, Olivier; Brandt, Timothy D.; Kasdin, N. Jeremy; Groff, Tyler D.; Lozi, Julien; Chilcote, Jeffrey; Hodapp, Klaus W.; Jovanović, Nemanja; Martinache, Frantz; Skaf, Nour; Lyra, Wladimir; Tamura, Motohide; Asensio-Torres, Rubén; Dong, Ruobing; Grady, C. A.; Gerard, Benjamin L.; Fukagawa, Misato; Hand, Derek; Hayashi, Masahiko; Henning, Thomas; Kudo, Tomoyuki; Kuzuhara, Masayuki; Kwon, Jungmi; McElwain, Michael W.; Uyama, Taichi

doi:10.3847/2041-8213/ab1b42

Cited by 99 publications

(112 citation statements)

References 59 publications

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“…Zhu 2015;Eisner 2015;Szulágyi et al 2019), further helping L -band observations even where the embedded planets may not be directly detectable. Indeed, L -band observations were key for detecting the few forming planet candidates that we know of today, namely LkCa 15 b (Kraus & Ireland 2012), HD 100546 b , HD 169142 b (Biller et al 2014;Reggiani et al 2014), MWC 758 b (Reggiani et al 2018), and PDS 70 b , even though all but the last one are still debated (Currie et al 2019;Rameau et al 2017;Ligi et al 2018;Wagner et al 2019). Further advantages of the L -band are, for example, that scattering from circumstellar disc material, which increases the A162, page 3 of 23 A&A 635, A162 (2020) noise and the probability of false positives, and contamination by background objects are less severe than at shorter wavelengths.…”

Section: Survey Goals and Strategymentioning

confidence: 99%

ISPY-NACO Imaging Survey for Planets around Young stars

Launhardt

Henning

Quirrenbach

et al. 2020

A&A

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Context. The occurrence rate of long-period (a 50 au) giant planets around young stars is highly uncertain since it is not only governed by the protoplanetary disc structure and planet formation process, but also reflects both dynamical re-structuring processes after planet formation as well as possible capture of planets not formed in situ. Direct imaging is currently the only feasible method to detect such wide-orbit planets and constrain their occurrence rate. Aims. We aim to detect and characterise wide-orbit giant planets during and shortly after their formation phase within protoplanetary and debris discs around nearby young stars. Methods. We carry out a large L -band high-contrast direct imaging survey for giant planets around 200 young stars with protoplanetary or debris discs using the NACO instrument at the ESO Very Large Telescope on Cerro Paranal in Chile. We use very deep angular differential imaging observations with typically >60 • field rotation, and employ a vector vortex coronagraph where feasible to achieve the best possible point source sensitivity down to an inner working angle of about 100 mas. This paper introduces the NACO Imaging Survey for Planets around Young stars (NACO-ISPY), its goals and strategy, the target list, and data reduction scheme, and presents preliminary results from the first 2.5 survey years. Results. We achieve a mean 5 σ contrast of ∆L = 6.4 ± 0.1 mag at 150 mas and a background limit of L bg = 16.5 ± 0.2 mag at >1. 5. Our detection probability is >50% for companions with 8 M Jup at semi-major axes of 80-200 au and >13 M Jup at 30-250 au. It thus compares well to the detection space of other state-of-the-art high-contrast imaging surveys. We have already contributed to the characterisation of two new planets originally discovered by VLT/SPHERE, but we have not yet independently discovered new planets around any of our target stars. We have discovered two new close-in low-mass stellar companions around R CrA and HD 193571 and report in this paper the discovery of close co-moving low-mass stellar companions around HD 72660 and HD 92536. Furthermore, we report L -band scattered light images of the discs around eleven stars, six of which have never been imaged at L -band before. Conclusions. The first 2.5 yr of the NACO-ISPY survey have already demonstrated that VLT/NACO combined with our survey strategy can achieve the anticipated sensitivity to detect giant planets and reveal new close stellar companions around our target stars.

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Section: Survey Goals and Strategymentioning

confidence: 99%

ISPY-NACO Imaging Survey for Planets around Young stars

Launhardt

Henning

Quirrenbach

et al. 2020

A&A

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“…Quanz et al 2013;Sallum et al 2015), but later discarded as imaging artefacts (e.g. Rameau et al 2017;Currie et al 2019).…”

Section: Introductionmentioning

confidence: 99%

Dust-depleted Inner Disks in a Large Sample of Transition Disks through Long-baseline ALMA Observations

Francis

Marel

2020

ApJ

154

145

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Transition disks with large inner dust cavities are thought to host massive companions. However, the disk structure inside the companion orbit and how material flows toward an actively accreting star remain unclear. We present a high resolution continuum study of inner disks in the cavities of 38 transition disks. Measurements of the dust mass from archival Atacama Large Millimeter/Submillimeter Array observations are combined with stellar properties and spectral energy distributions to assemble a detailed picture of the inner disk. An inner dust disk is detected in 18 of 38 disks in our sample. Of the 14 resolved disks, 8 are significantly misaligned with the outer disk. The near-infrared excess is uncorrelated with the mm dust mass of the inner disk. The size-luminosity correlation known for protoplanetary disks is recovered for the inner disks as well, consistent with radial drift. The inner disks are depleted in dust relative to the outer disk and their dust mass is uncorrelated with the accretion rates. This is interpreted as the result of radial drift and trapping by planets in a low α (∼ 10 −3 ) disk, or a failure of the α-disk model to describe angular momentum transport and accretion. The only disk in our sample with confirmed planets in the gap, PDS 70, has an inner disk with a significantly larger radius and lower inferred gas-to-dust ratio than other disks in the sample. We hypothesize that these inner disk properties and the detection of planets are due to the gap having only been opened recently by young, actively accreting planets.

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“…For postprocessing PSF subtraction we implemented two reduction techniques: (1) RDI by following the way of Currie et al (2019) to capture the ring morphology without selfsubtraction;…”

Section: Data Reduction and Resultsmentioning

confidence: 99%

SCExAO/CHARIS High-contrast Imaging of Spirals and Darkening Features in the HD 34700 A Protoplanetary Disk

Uyama

Currie

Christiaens

et al. 2020

ApJ

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We present Subaru/SCExAO+Coronagraphic High Angular Resolution Imaging Spectrograph (CHARIS) broadband (JHK-band) integral field spectroscopy of HD 34700 A. CHARIS data recover HD 34700 A's disk ring and confirm multiple spirals discovered by Monnier et al. We set limits on substellar companions of ∼12 M Jup at 0 3 (in the ring gap) and ∼5 M Jup at 0 75 (outside the ring). The data reveal darkening effects on the ring and spiral, although we do not identify the origin of each feature such as shadows or physical features related to the outer spirals. Geometric albedos converted from the surface brightness suggest a greater scale height and/or prominently abundant submicron dust at position angles between ∼45°and 90°. Spiral fitting resulted in very large pitch angles (∼30°-50°); a stellar flyby of HD 34700 B or infall from a possible envelope is perhaps a reasonable scenario to explain the large pitch angles.

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No Clear, Direct Evidence for Multiple Protoplanets Orbiting LkCa 15: LkCa 15 bcd are Likely Inner Disk Signals

Cited by 99 publications

References 59 publications

ISPY-NACO Imaging Survey for Planets around Young stars

ISPY-NACO Imaging Survey for Planets around Young stars

Dust-depleted Inner Disks in a Large Sample of Transition Disks through Long-baseline ALMA Observations

SCExAO/CHARIS High-contrast Imaging of Spirals and Darkening Features in the HD 34700 A Protoplanetary Disk

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