Washington: Scientists have discovered that stars, which are similar to the sum, explode too when they die.
The birth of planetary nebulae, resulting from the death of low and intermediate mass stars, is usually thought of as a slow process, in contrast with the intense supernovae that massive stars produce. But a recent study led by researchers at the Institute of Astrophysics of Andalusia (IAA-CSIC) has revealed the fact that explosive phenomena also intervene in the formation of planetary nebulae.
Jose Francisco Gomez, IAA-CSIC researcher in charge of the project, said that in a few thousand million years, the sun will exhaust its nuclear fuel, expand into a red giant and eject a major part of its mass, resulting into a white dwarf surrounded by a glowing planetary nebula. Even though every star with a mass below ten solar masses goes through this short but important final transition, many details of the process still evade us.
The study of IRAS 15103-5754, part of a group of sixteen objects known as ‘water fountains’, has yielded important clues concerning this final stage. ‘Water fountains’ are mature stars in a state of transition from red giants to planetary nebulae which display jets of ejected material that can be detected from intense radiation produced by water vapor molecules (water maser emission).
IRAS 15103-5754 stands out within the small group under study because it has been observed that the velocity of the material inside the jet increases in proportion to the distance from the central star.
Luis F. Miranda (IAA-CSIC, University of Vigo) said that in IRAS 15103-5754 they saw, for the first time, a water maser emission at velocities of hundreds of kilometers per second, witnessing the transition of a star into a planetary nebula in real time.
Francisco Gomez added that the high velocity could only be explained by the occurrence of an explosion. As per their results, contrary to the most widespread theories, when a star turns into a planetary nebula an enormous explosion is produced – short-lived but highly energetic – which will determine the evolution of the star in its last phases of life.