National Astronomical Observatory of Japan | 2019 Dec 23
Astronomers using the Atacama Large Millimeter/submillimeter Array (ALMA) found a young star surrounded by an astonishing mass of gas. The star, called 49 Ceti, is 40 million years old and conventional theories of planet formation predict that the gas should have disappeared by that age. The enigmatically large amount of gas requests a reconsideration of our current understanding of planet formation.
Planets are formed in gaseous dusty disks called protoplanetary disks around young stars. Dust particles aggregate together to form Earth-like planets or to become the cores of more massive planets by collecting large amounts of gas from the disk to form Jupiter-like gaseous giant planets. According to current theories, as time goes by the gas in the disk is either incorporated into planets or blown away by radiation pressure from the central star. In the end, the star is surrounded by planets and a disk of dusty debris. This dusty disk, called a debris disk, implies that the planet formation process is almost finished.
Recent advances in radio telescopes have yielded a surprise in this field. Astronomers have found that several debris disk still possess some amount of gas. If the gas remains long in the debris disks, planetary seeds may have enough time and material to evolve to giant planets like Jupiter. Therefore, the gas in a debris disk affects the composition of the resultant planetary system. ...
First Subarcsecond Submillimeter-wave [C I] Image of 49 Ceti with ALMA ~ Aya E. Higuchi et al
- Astrophysical Journal 883(2):180 (2019 Oct 01) DOI: 10.3847/1538-4357/ab3d26
- arXiv.org > astro-ph > arXiv:1908.07032 > 19 Aug 2019
in a Gaseous Debris Disk of 49 Ceti with ALMA ~ Aya E. Higuchi et al
- Astrophysical Journal Letters 885(2):L39 (2019 Nov 10) DOI: 10.3847/2041-8213/ab518d
- arXiv.org > astro-ph > arXiv:1909.09748 > 21 Sep 2019 (v1), 24 Oct 2019 (v2)