June 20, 2018

08.05.10: Does Type Ia Supernova Formation Need Revision?

A key measurement device used by modern astrophysicists may also hold an elusive mystery. It has been long known that a Type Ia supernova occurs when a white dwarf accretes in-falling material from a binary companion, grows past the Chandrasekhar limit of 1.4 solar masses, and promptly blows itself up in a thermonuclear chain reaction that can be seen across the universe. These brilliant displays rise in brightness and then fade in a predictable fashion, allowing them to serve as “standard candles” marking the intergalactic distances to their host galaxies. These accreting white dwarfs should give off copious amounts of X-rays leading up to their eventual ignition. If this is the case, where are these accreting white dwarf SN Ia’s in waiting? An interesting study was released earlier this year by Akos Bogdan and Marat Gilfanov of the Max Planck Institute. Analyzing five elliptical galaxies and the nearby Andromeda with NASA’s Chandra X-Ray observatory, they found X-Ray output to be up to 50 times less than expected if the seeds for Type Ia’s were indeed being sown. Several factors may account for this discrepancy;

  1. Perhaps energetic accretion is not a constant state in these binary systems;
  2. The types of galaxies surveyed (with the exception of Andromeda) are not known for their energetic star formation;
  3. Type Ia’s may be more prevalent during certain epochs of star formation in the universe;
  4. Other mechanisms, such as merging white dwarf binaries, may produce Type Ia supernovae without accretion. But these populations would surely be lower throughout the universe than mixed systems; it isn’t even clear if a merging white dwarf pair would explode, or simply collapse into a neutron star. And white dwarfs are just plain tough to spot at galactic distances!

Whatever is the case, there still isn’t a consensus in the astronomical community as to where the Type Ia’s-in-waiting are hiding. It should be noted that this controversy does not center on the luminosity relationship;   naysayers look elsewhere for your chink in the frame-work of the Big Bang Theory! Instead, we suspect that “sub-breeds” Of Type Ia (Type IAa?) supernovae will come to light as new platforms such as James Webb Space Telescope come on line in the next decade.

24.04.10-Our Existence: Justified.

The formation of the Earth poses a key dilemma to planetary accretionary theory; namely, why are we here at all? Standard models would say that the Earth and other planets coalesced out of the proto-solar nebula to form. However, spiral density waves within the same nebula should have drawn down orbital energy to shorten the planets orbit, slowly drawing it in. Looking at other “hot Jupiter” systems, that’s just what we see; large gas giant worlds that formed further out, only to migrate inward into tight orbits… just how did we end up in our nice, neat orbit?

Now, computational astrophysicist Mordecai-Mark Mac Loc at the American Museum of Natural History may have the answer. Accounting for temperature and spin variability, resonance key holes can occur; planets like Earth may simply spiral inward and get hung up in these safe zones between dragging pressure waves. Of course, a majority of proto-planets don’t make the cut and simply spiral inward to a fiery end, but they’re not around for us to see today. One discovery that would perhaps give observational weight to this theory would be the discovery of exo-Earths also parked in nice neat orbits… the Kepler space telescope may pave the way for this discovery as it stares off into Cygnus. For now, thank computational mathematics that you’re here reading this, just as it says you should be!