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Post Info TOPIC: HD 141569
Blobrana


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HD 141569 A
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Title: Characterisation of the inner disk around HD 141569 A from Keck/NIRC2 L-band vortex coronagraphy
Author: Dimitri Mawet, Elodie Choquet, Olivier Absil, Elsa Huby, Michael Bottom, Eugene Serabyn, Bruno Femenia, Jérémy Lebreton, Keith Matthews, Carlos A. Gomez Gonzalez, Olivier Wertz, Brunella Carlomagno, Valentin Christiaens, Denis Defrère, Christian Delacroix, Pontus Forsberg, Serge Habraken, Aissa Jolivet, Mikael Karlsson, Julien Milli, Christophe Pinte, Pierre Piron, Maddalena Reggiani, Jean Surdej, Ernesto Vargas Catalan

HD 141569 A is a pre-main sequence B9.5 Ve star surrounded by a prominent and complex circumstellar disk, likely still in a transition stage from protoplanetary to debris disk phase. Here, we present a new image of the third inner disk component of HD 141569 A made in the L' band (3.8 micron) during the commissioning of the vector vortex coronagraph recently installed in the near-infrared imager and spectrograph NIRC2 behind the W.M. Keck Observatory Keck II adaptive optics system. We used reference point spread function subtraction, which reveals the innermost disk component from the inner working distance of \simeq 23 AU and up to \simeq 70 AU. The spatial scale of our detection roughly corresponds to the optical and near-infrared scattered light, thermal Q, N and 8.6 micron PAH emission reported earlier. We also see an outward progression in dust location from the L'-band to the H-band (VLT/SPHERE image) to the visible (HST/STIS image), likely indicative of dust blowout. The warm disk component is nested deep inside the two outer belts imaged by HST NICMOS in 1999 (respectively at 406 and 245 AU). We fit our new L'-band image and spectral energy distribution of HD 141569 A with the radiative transfer code MCFOST. Our best-fit models favour pure olivine grains, and are consistent with the composition of the outer belts. While our image shows a putative very-faint point-like clump or source embedded in the inner disk, we did not detect any true companion within the gap between the inner disk and the first outer ring, at a sensitivity of a few Jupiter masses.

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Blobrana


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RE: HD 141569
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Title: Resolved Gas Interior to the Dust Rings of the HD 141569 Disk
Author: Kevin M. Flaherty, A. Meredith Hughes, Sean M. Andrews, Chunhua Qi, David J Wilner, Aaron C. Boley, Jacob A. White, Will Harney, Julia Zachary

The disk around HD 141569 is one of a handful of systems whose weak infrared emission is consistent with a debris disk, but still has a significant reservoir of gas. Here we report spatially resolved mm observations of the CO(3-2) and CO(1-0) emission as seen with the SMA and CARMA. We find that the excitation temperature for CO is lower than expected from cospatial blackbody grains, similar to previous observations of analogous systems, and derive a gas mass that lies between that of gas-rich primordial disks and gas-poor debris disks. The data also indicate a large inner hole in the CO gas distribution and an outer radius that lies interior to the outer scattered light rings. This spatial distribution, with the dust rings just outside the gaseous disk, is consistent with the expected interactions between gas and dust in an optically thin disk. This indicates that gas can have a significant effect on the location of the dust within debris disks.

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HD 141569 is a blue-white dwarf star approximately 320 light-years away in the constellation of Libra. The primary star has two red dwarf companions (orbiting each other) at about nine arcseconds.
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Title: The Gemini NICI Planet-Finding Campaign: Asymmetries in the HD 141569 disc
Author: Beth A. Biller, Michael C. Liu, W. Ken Rice, Zahed Wahhaj, Eric Nielsen, Thomas Hayward, Marc Kuchner, Laird M. Close, Mark Chun, Christ Ftaclas, Douglas W. Toomey

We report here the highest resolution near-IR imaging to date of the HD 141569A disc taken as part of the NICI Science Campaign. We recover 4 main features in the NICI images of the HD 141569 disc discovered in previous HST imaging: 1) an inner ring / spiral feature. Once deprojected, this feature does not appear circular. 2) an outer ring which is considerably brighter on the western side compared to the eastern side, but looks fairly circular in the deprojected image. 3) an additional arc-like feature between the inner and outer ring only evident on the east side. In the deprojected image, this feature appears to complete the circle of the west side inner ring and 4) an evacuated cavity from 175 AU inwards. Compared to the previous HST imaging with relatively large coronagraphic inner working angles (IWA), the NICI coronagraph allows imaging down to an IWA of 0.3". Thus, the inner edge of the inner ring/spiral feature is well resolved and we do not find any additional disc structures within 175 AU. We note some additional asymmetries in this system. Specifically, while the outer ring structure looks circular in this deprojection, the inner bright ring looks rather elliptical. This suggests that a single deprojection angle is not appropriate for this system and that there may be an offset in inclination between the two ring / spiral features. We find an offset of 4±2 AU between the inner ring and the star center, potentially pointing to unseen inner companions.

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