* Astronomy

Blobrana · L

RE: HD 61005

Blobrana · L

Title: Hubble Space Telescope Optical Imaging of the Eroding Debris Disk HD 61005
Authors: H. L. Maness, P. Kalas, K. M. G. Peek, E. I. Chiang, K. Scherer, M. P. Fitzgerald, James R. Graham, D. C. Hines, G. Schneider, S. A. Metchev

We present Hubble Space Telescope optical coronagraphic polarization imaging observations of the dusty debris disk HD 61005. The scattered light intensity image and polarisation structure reveal a highly inclined disk with a clear asymmetric, swept back component, suggestive of significant interaction with the ambient interstellar medium. The combination of our new data with the published 1.1 micron discovery image shows that the grains are blue scattering with no strong colour gradient as a function of radius, implying predominantly sub-micron sized grains. We investigate possible explanations that could account for the observed swept back, asymmetric morphology. Previous work has suggested that HD 61005 may be interacting with a cold, unusually dense interstellar cloud. However, limits on the intervening interstellar gas column density from an optical spectrum of HD 61005 in the Na I D lines render this possibility unlikely. Instead, HD 61005 may be embedded in a more typical warm, low-density cloud that introduces secular perturbations to dust grain orbits. This mechanism can significantly distort the ensemble disk structure within a typical cloud crossing time. For a counterintuitive relative flow direction--parallel to the disk midplane--we find that the structures generated by these distortions can very roughly approximate the HD 61005 morphology. Future observational studies constraining the direction of the relative interstellar medium flow will thus provide an important constraint for future modelling. Independent of the interpretation for HD 61005, we expect that interstellar gas drag likely plays a role in producing asymmetries observed in other debris disk systems, such as HD 15115 and Delta-Velorum.

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Blobrana · L

Every time we look at anything in astronomy, in a new way, we've discovered things that we didn't expect.
Thats astronomer Dean Hines, speaking from a 2008 meeting. He found planets being born around the star science HD 61005 - it's about 113 light years from Earth. And what surprised him is what he calls, "the moth."
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Object Name:     HD 61005
Object Description:    Star with Circumstellar Structure
Constellation:    Puppis
Distance:    100 light-years or 31 parsecs

HD 61005.kmz
Google Sky file (1kb, kmz)

Position (J2000):    R.A. 07h 35m 47s.46 Dec. -32° 12' 14".04

Blobrana · L

What superficially resembles a giant moth floating in space is giving astronomers new insight into the formation and evolution of planetary systems. This is not your typical flying insect. It has a wingspan of about 22 billion miles. The wing- like structure is actually a dust disk encircling the nearby, young star HD 61005, dubbed "The Moth." Its shape is produced by starlight scattering off dust. Dust disks around roughly 100-million-year-old stars like HD 61005 are typically flat structures where planets can form. But images taken with NASA's Hubble Space Telescope of "The Moth" are showing that some disks sport surprising shapes.

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