PR 21-1999: A Butterfly-Shaped 'Papillon Nebula Yields Secrets of Massive Star Birth
10 Jun 1999Newborn stars are difficult to observe because they are always hidden within dense clouds of dust. And if the star is really a massive one, say 10 times heavier than our Sun, spotting the starbirth is almost impossible: massive stars evolve so quickly that by the time the dust disperses they are 'teenagers', not babies anymore, 20% of their lifetime has already passed. Using the ESA/NASA Hubble Space Telescope a team of European astronomers * has been able to pinpoint several of these massive baby stars, one of which has created - while evolving - an impressive butterfly-shaped nebula of dust around it during its early life.
The newly found massive newborn stars are in one of our satellite galaxies, the Large Magellanic Cloud (LMC), 170 000 light-years away - right on our cosmic backyard. The Hubble image shows a view of a turbulent cauldron of starbirth, unromantically called N159. Fierce stellar winds from the hot newborn massive stars sculpt ridges, arcs and filaments in the vast cloud, which is over 150 light-years across. This is the clearest image ever obtained of this region.
Seen for the first time is the butterfly-shaped or 'Papillon' (French for butterfly) nebula, buried in the centre of the maelstrom of glowing gases and dark dust. The unprecedented details of the structure of the Papillon, itself less than 2 light-years in size (about 1/2000th of a degree in the sky), are seen in the inset.
This bipolar shape might be explained by the outflow of gas from the massive star (over 10 times the mass of our Sun) hidden in the central absorption zone. Such stars are so hot and bright that the pressure created by their sunlight halts the infall of gas and directs it away from the star in two opposite directions. This mechanism is not fully understood, but presumable the outflow is constrained around the star's equator and directed to escape along the star's rotation axis.
This observation is part of a search for young massive stars in the LMC. This buttefly-shaped nebula is considered to be a rare class of compact 'blob' around newborn, massive stars. The red in this true-colour image comes from the emission of hydrogen and the yellow from hotter oxygen gas. The picture was taken on 5 September 1998 with the Wide Field Planetary Camera 2.
(*) The team of European astronomers:
Dr. Mohammad Heydari-Malayeri
Dr. Michael R. Rosa
Dr. Hans Zinnecker
Dr. Lise Deharveng
Dr. Vassilis Charmandaris
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