Instruct: Identify the main and secondary category of Arxiv papers based on the titles and abstracts
Query: New attempts to understand nanodiamond stardust   We report on a concerted effort aimed at understanding the origin and history
of the pre-solar nanodiamonds in meteorites including the astrophysical sources
of the observed isotopic abundance signatures. This includes measurement of
light elements by secondary ion mass spectrometry (SIMS), analysis of
additional heavy trace elements by accelerator mass spectrometry (AMS) and
dynamic calculations of r-process nucleosynthesis with updated nuclear
properties. Results obtained indicate: a) there is no evidence for the former
presence of now extinct 26Al and 44Ti in our diamond samples other than what
can be attributed to silicon carbide and other "impurities"; this does not
offer support for a supernova (SN) origin but neither does it negate it; b)
analysis by AMS of platinum in "bulk diamond" yields an overabundance of r-only
198Pt that at face value seems more consistent with the neutron burst than with
the separation model for the origin of heavy trace elements in the diamonds,
although this conclusion is not firm given analytical uncertainties; c) if the
Xe-H pattern was established by an unadulterated r-process, it must have been a
strong variant of the main r-process, which possibly could also account for the
new observations in platinum.

13
The categories of this paper are: quant-ph
21
The categories of this paper are: adap-org
15
The categories of this paper are: nucl-ex
30
The categories of this paper are: q-alg
18
The categories of this paper are: econ
28
The categories of this paper are: alg-geom
35
The categories of this paper are: mtrl-th
19
The categories of this paper are: eess
11
The categories of this paper are: hep-lat
37
The categories of this paper are: supr-con
27
The categories of this paper are: comp-gas
26
The categories of this paper are: bayes-an
17
The categories of this paper are: q-fin
3
The categories of this paper are: physics
5
The categories of this paper are: gr-qc
20
The categories of this paper are: acc-phys