"Prompt" vs "Delayed" SNIa from WD age, Temp. ?

[Widdekind]

According to Howell 2007:

 

Recent studies indicate that Type Ia supernovae (SNe Ia) consist of two groups — a “prompt” component, whose rates are proportional to the host galaxy star formation rate, whose members have broader light curves, and are intrinsically more luminous; and, a “delayed” component, whose members take several Gyr to explode, have narrower light curves, and are intrinsically fainter. As cosmic star formation density increases with redshift, the prompt component should begin to dominate.

Now, WDs, which were "several Gyr" old, at time of SNIa, would be considerably older, colder & dimmer, lying lower, and to the right, on the HR-Diagram. Thus, could initial WD age / temperature, conceivably determine, the ensuing "luminosity trajectories", across the HR-diagram ?? Again, and conversely, younger, hotter (bluer) WDs, initially lying higher & and to the left on the HR-diagram, would presumably generate the brighter, longer-lasting SNIa's; whereas, colder & older WDs would, presumably, generate the dimmer & faster-fading SNIa's.

 

To make an engine analogy, younger hotter WD "cores" could, conceivably, "combust completely"; whereas, older & colder "spent cores" might, possibly, only "partially combust", like an out-of-tune engine with old corroded spark plugs. The following "suggestive schematic" attempts to illustrate this suggestion / question:

 

[pantheory]

Although I see logic in your proposal, there may be a problem. Theory concerning Type 1a supernova involves two possibilities. One is that a white dwarf star sucks the atmosphere from a surrounding red giant star in a close orbiting binary star system causing the white dwarf star to explode. The other possibility discussed is the collision of two white dwarf stars in a close binary system. In both cases a white dwarf star is thought to be exploding. If the supernova explosion does not meet the required profile concerning spectrum, brightness, after glow profile involving rate and time of dimming, etc. then it would not be considered a type 1a profile and classified differently. Such white dwarf stars are thought to be between .5 and 1 solar masses. These explosions are very uniform. That is why they are considered to be standard candles. Although there are some recognized variations within this select group, if there is very much difference in the profile of radiation then it will be otherwise classified so that your ideas might only explain minor variations. If more differences are recognized in time, then more supernova might be otherwise classified to the benefit of the data base. It will be a good thing when the causes of differences are better understood so that those that do not meet a more stringent profile, will not be considered type 1a standard candles and data averaging (redshift bin data) will become more accurate.

Edited June 23, 2011 by pantheory

[Widdekind]

Astronomers refer to this routine, and relatively minor, re-calibration of SNIa light-curves, as 'stretch'. To wit, the bigger & brighter blasts, have higher peak brightness, and persist longer ("taller & wider"), and conversely. The height, and width, of the light curve scale together, so that, with a single 'stretch' parameter, all SNIa light-curves approximately coincide.

 

The fact remains, that the typical SNIa absolute luminosity, of M = -19.3, corresponds to the luminosity L = R² T⁴, of a WD / earth-radius object, at star core temperatures (10s MK). Such suggests, that what is actually happening, is the brief, runaway, fusion re-ignition-and-explosion, of a re-activated star core.

[pantheory]

Sounds like a reasonable explanation to me I have not studied 1a normal light profiles much but have studied binned data extensively concerning the asserted dark energy hypothesis and as a result reformulated the Hubble formula attempting to otherwise explain 1a observations as standard candles without needing dark energy (by using another cosmological model).