research bits

Soker Akashi

Muhammad Akashi and Noam Soker present in “Nature Astronomy”

along with 70 colleagues from many other institutes in all continents, new findings concerning the Southern Ring Nebula. The main discovery: the complicated structure of this planetary nebula was shaped by four or five stars and not by two stars as in most other cases.  Observations with the new infrared space telescope, JWST, allowed this discovery.   Planetary nebulae are formed in the final stages of stellar evolution during the death of sun-like stars. A star is a gaseous sphere that produces energy in the process of nuclear fusion. Its shape is determined by the interplay between gravity, which pulls the gas to the center of the sphere, and fusion, which creates an outward pressure. When the elements required for the fusion process run out, gravity dominates and the star shrinks into a "white dwarf"; At the same time, the outer shell of the star is thrown into space and creates a gas cloud about the size of a light year. The gas cloud is called a planetary nebula. Our sun is also expected to form a planetary nebula in about 6 billion years.


The Southern Ring Nebula, or by its scientific name NGC 3132, is part of the Milky Way, and its distance from Earth is about 2,500 light years. According to the common hypothesis, most planetary nebulae are formed from pairs of stars, but the new research indicates that in the interesting case of the Southern Ring Nebula, four and possibly even five stars were involved. Two of the stars are visible in the telescope images. The other three stars have not yet been observed, and their existence was deduced from the calculations of the Technion researchers and their colleagues. Some features result from shaping by jets that the closest stellar companion launched, according to numerical simulations by Akashi and Soker.


NASA Press Release




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Image Credits: SCIENCE: NASA, ESA, CSA, STScI, Orsola De Marco (Macquarie University). IMAGE PROCESSING: Joseph DePasquale (STScI)