NAOJ: Unraveling a Spiral Stream of Dusty Embers

[bystander]

Unraveling a Spiral Stream of Dusty Embers
from a Massive Binary Stellar Forge
Subaru Telescope | National Astronomical Observatory of Japan | 2020 Sep 16

Sequence of 7 mid-IR (~10 micrometers) images of WR 112 taken between 2001 – 2019 by Gemini North, Gemini South, Keck, the Very Large Telescope (VLT), and the Subaru Telescope. The length of the white line on each image corresponds to about 6800 astronomical units. (Credit: Lau et al, 2020 ApJ)

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With almost two decades of mid-infrared (IR) imaging from the largest observatories around the world including the Subaru Telescope, a team of astronomers was able to capture the spiral motion of newly formed dust streaming from the massive and evolved binary star system Wolf-Rayet (WR) 112. Massive binary star systems, as well as supernova explosions, are regarded as sources of dust in the Universe from its early history, but the process of dust production and the amount of the ejected dust are still open questions.

WR 112 is a binary system composed of a massive star in the very late stage of stellar evolution losing a large amount of mass and another massive star at the main sequence. Dust is expected to be formed in the region where stellar winds from these two stars are colliding. The study reveals the motion of the dusty outflow from the system and identifies WR 112 as a highly efficient dust factory that produces an entire Earth mass of dust every year. ...

This binary dust formation phenomenon has been revealed in other systems such as WR 104 ... WR 104, in particular, reveals an elegant trail of dust resembling a 'pinwheel' that traces the orbital motion of the central binary star system.

However, the dusty nebula around WR 112 is far more complex than a simple pinwheel pattern. Decades of multi-wavelength observations presented conflicting interpretations of the dusty outflow and orbital motion of WR 112. After almost 20 years uncertainty on WR 112, images from the COMICS instrument on the Subaru Telescope taken in Oct 2019 provided the final—and unexpected—piece to the puzzle. ...

Unraveling a Spiral Stream of Dusty Embers
from a Massive Binary Stellar Forge
W. M. Keck Observatory | 2020 Sep 16

Resolving Decades of Periodic Spirals from the Wolf–Rayet Dust Factory WR 112 ~ Ryan M. Lau et al

• Astrophysical Journal 900(2):190 (2020 Sep 10) DOI: 10.3847/1538-4357/abaab8
• arXiv.org > astro-ph > arXiv:2008.01093 > 03 Aug 2020