An Annum circa ~4567 Mega-Anna in the life of our Sun

The archived evidence of a superflare from the Sun and rapid transport of early Solar system solids in the proto-planetary disk is inferred from the fossil evidence of a short-lived now-extinct radionuclide, 7Be, in the Efremovka meteorite.

Mar 25, 2019
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Our contemporary Sun, at its midlife ~4600 million years, suffers from the crisis of staid monotony. On the contrary, at its birth and during the nascent years, the Sun, like all its peers, is expected to be ebullient, effervescent, and highly dynamic, energetic characterized by frenetic growth, magnetic activity, outflows despite being ~10% dim (wit !!) optically. The general characteristics though being same amongst its peers, the individual path of redemption during the tottering years of the pre-main sequence in the life of our Sun determined the grand architecture of the  planetary system in a very short period of  a few million years. Consequently creating cradles for the tree of life in some nook of its left over ‘wandering’ shard aka “planet”- the Earth. Collating this picturesque pictorial album of our Sun during the eventful genesis is critical towards our understanding in detail the origin and evolution of star and its planetary system and establishing the ‘Rosetta stone’ on terra firma for our adventures and quests of “ET life” on other stellar systems in milky way, et alia. The stochastic nature of events and the causality between physics and chemistry determine the, currently unknown, episodic nature, timescale of these early Solar system events like flares, outflows, collisional, turbulent growth of solids to planetesimals, thermal and abundance profile of the solids in the protoplanetary disk. 

The paper https://doi.org/10.1038/s41550-019-0716-0  attempts to resolve a conundrum and bridge the gaps in our understanding of the origin and early evolution of the Solar system. 

The fossil isotopic records of a few suitable short-lived now-extinct radionuclides (e.g. 26Al, 60Fe, 7Be, etc.), in the form of their daughter nuclides, are key tracers and time trackers of these early Solar system events and processes. Meteorites are the ‘frozen archives’ of the primal epoch and studies of various components can enhance the crucial understanding about the formation and early evolution of our Solar system in particular and stellar systems in general. By combining study of radiogenic decay of two different radionuclides (7Be, 10Be) of the element Beryllium (Be) with orders of magnitude difference in characteristic half-life (53 days  and 1.38 Ma, respectively) within the earliest forming solid aka calcium-, aluminium rich inclusions (CAIs) (see figure below), very high resolution chronology of the early Solar system events and processes could be gleaned. The in situ Lithium-Beryllium- Boron isotopic study carried out using secondary ion mass spectrometer at Physical Research Laboratory, Ahmedabad, India in a CAI from Efremovka meteorite yielded following

  • The time‘X’ (read s) of a Million times Sun: The observed abundance of 7Be, 10Be necessitate the interaction of X ray intensities/ luminosity (Lx) of the Sun of ~1032 erg sec-1 with the solid and gaseous precursors of the CAI. Thus, documenting a first confirm specific record of a ‘superflare’ from our Sun. This super flare event is about a Million times stronger than the “Carrington event of 1859” the strongest Solar flare ever recorded. Such superflares on other sun-like stars have been recently inferred by observations from NASA's Kepler mission. 
  • Fast Ferris Phantom Wheels: The short half-life of 7Be of ~53 days combined with the expected rapid diffusion of lithium within melilite (analysed mineral) implies that the preservation of the isotopic records in the CAIs is evidence of an outward transporting mechanics/ mechanism (bipolar winds, outflows, X-winds) in the early Solar system that were such that the CAIs and their akin‘s’ (kith and kin) were transported from the superflare regions to cooler temperatures in about a year time.
  • Ra-the Sun God, Amun-Ra, and the Genesis: The presence of 7Be along with 10Be establishes unequivocally transmutation/ genesis of  a fraction of Solar composition by solar energetic particle induced spallation reaction in a very high irradiation environment of  the early active Sun.

Mosaic of the studied Efremovka CAI (E40).
False coloured mosaic of the studied Efremovka CAI (E40). The abundance of silicon, calcium, titanium are shown by red, green, and blue colour. In this mosaic melilite, pyroxene, olivine, and spinel appear as green, blue to pinkish blue, and black, respectively. The scale bar is shown at the bottom of the image.

These restrictive inferences have important consequences for experimental and theoretical studies in the fields of astronomy, astrophysics, planetary sciences, nuclear physics, experimental petrology which significantly advance our current understanding of the formation and early evolution of the Solar system. 

These results spawn several questions (1) What were the irradiation history recorded by 'canonical' (characterized by 26Al/27Al = ~5.25×10-5) and Fractionation and Unidentified Nuclear effects (FUN) CAIs? (2) How is Beryllium and Lithium partitioned in melilite (akermanite Ca2Mg(Si2O7)- Ca2Al(AlSiO7) gehlenite) solid solution at the thermal minimum of the solid solution? (3) What fast does Lithium diffuse within melilite and what is the dependence with the akermanite content? (4) What fraction and how probable is the transport of solids created near reconnection regions of the Sun to be found in the outward regions? (5) How is the isotopic distribution of elements like Mg, B, and Li within CAIs of different sizes affected by the transport through the high temperature regions and their consequences on preservation of the isotopic records?

https://doi.org/10.1038/s41550-019-0716-0  

Meteoritic evidence of a late superflare as source of 7Be in the early Solar system


Ritesh Kumar Mishra

Cosmochemist, Planetary Scientist, Alexander von Humboldt Fellow , Ruprecht-Karls-Universität, Heidelberg

Cosmochemist, Secondary Ion Mass Spectrometrist. Interested in understanding consequences and causality of crisis, conflicts, and opportunities faced by Humans from scientific and socio-political stand points.

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