A New Kind of Star Solves an Old Problem

A New Kind of Star Solves an Old Problem

It is not every day that Hollywood discovers a new star that stands apart from all their other stars.

The same is true for astronomers. Only rarely do they discover a new kind of star that is unlike any they have seen before. When they do make such a discovery, however, it typically reveals new insights into how the universe was exquisitely designed to provide a home for life and for humanity in particular.

New insights indeed came from a new type of star discovered by four Spanish astrophysicists.1 What made their discovery so unusual was that they did not actually see the stars they described. Instead, they discerned their existence and their properties from known conditions of the early universe and from the measured abundances of different elements and isotopes (forms of a particular element exhibiting different numbers of neutrons in the nuclei of the atoms that make up the element) found in presolar grains (dust grains in the solar system’s interplanetary medium that pre-date the formation of the planets).

The newly discerned stars have been called primordial novae by the Spanish team. These primordial novae manifest properties that fall between those of supernovae and those of classical novae.

A supernova is a giant star that, at the end of its nuclear burning period, undergoes a cataclysmic eruption where for a period of about a month it outshines the light output from ten billion other stars. (This animation shows the violent death of a star.) During the eruption, the supernova’s nuclear furnace manufactures copious amounts of heavy elements (elements heavier than hydrogen and helium) that are then scattered throughout the interstellar medium.

A classical nova consists of a white dwarf star (a large star that has exhausted all of its nuclear fuel and is in the process of cooling down much like a cinder in a burnt-out fire) and a lower-mass star that has not yet consumed all of its nuclear fuel. The two stars orbit one another closely enough that the gravity of the white dwarf is able to steal matter from its companion. Eventually, the buildup of matter on the surface of the white dwarf ignites a violent thermonuclear reaction. The eruption, however, is typically several thousand times dimmer than that from a supernova, and the amount of heavy-element material ejected into interstellar space measures about a hundred thousand times less. Also, unlike supernovae that manufacture elements as heavy as uranium, neptunium, and plutonium, classical novae cannot make elements any heavier than chlorine.

The Spanish astronomy team noted that measurements made by other astronomers had established that when the universe was less than a billion years old, the quantity of heavy elements exploded into the interstellar medium by the first supernovae to form in the universe’s history added up to less than a hundred thousand times the quantity of heavy elements presently existing in the interstellar medium.2 The team’s calculations showed that this much lower level of heavy elements would permit a white dwarf star to accumulate far more material from a companion star than would be possible today. This extra accumulation of mass onto the surface of the white dwarf leads to far-more-violent and longer-lasting eruption. Such an eruption not only ejects much more heavy-element material into the interstellar medium, it also makes elements as heavy as copper and zinc.3

Recognizing that nova eruption events are about 1,500 times more frequent than those from supernovae, the Spanish astronomy team determined that—unlike classical novae—the heavy elements scattered into the interstellar medium by primordial novae will add up to a substantial fraction of that scattered by supernovae. Also, the kinds of heavy elements produced by primordial nova eruptions would be distinct from those produced by supernovae.

These conclusions about the quantity and kinds of heavy elements produced and scattered by primordial novae solve a long-standing problem in solar system chemistry and physics. That problem is that presolar grains in the interplanetary medium of the solar system manifest a distribution of elements and isotopes that cannot be completely explained by heavy-element contributions from supernovae alone. Primordial novae complete the explanation.

The extra heavy elements that primordial novae contributed to the gas cloud that formed the solar system play a critical role in providing the resources needed for advanced life and, particularly, the resources needed to launch and sustain high-technology civilization. If it were not for our Milky Way Galaxy producing just the right number of primordial novae (not too many and not too few) at just the right times, we humans might not exist. And we certainly would not enjoy our present standard of living. Primordial novae help demonstrate the biblical principle that the more we study the universe and the record of nature, the more evidence we will uncover of God’s existence and of His handiwork in preparing His creation for the benefit of life and the human species in particular.

Will astronomers ever be able to directly image primordial novae? Probably not. Given that the formation of primordial novae ceased more than 12 billion years ago, one would need to look more than 12 billion light years away in order to see them. Astronomers lack the technology to image supernovae that are more than 10 billion light years away. Since primordial novae will be about 40 times dimmer than supernovae, there is not much hope of detecting them with foreseeable technology.

  1. Jordi José et al., “The First Nova Explosions,” Astrophysical Journal Letters 662 (June 20, 2007): L103-L106.
  2. Judith G. Cohen et al., “A New Type of Extremely Metal-Poor Star,” Astrophysical Journal Letters 659 (April 20, 2007): L161-L164.
  3. Jordi José et al., L104.