  Metrics based on reference lists of research articles or on keywords have
been used to predict citation impact. The concept behind such metrics is that
original ideas stem from the reconfiguration of the structure of past
knowledge, and therefore atypical combinations in the reference lists,
keywords, or classification codes indicate future high impact research. The
current paper serves as an introduction to this line of research for
astronomers and also addresses some methodological questions of this field of
innovation studies. It is still not clear if the choice of particular indexes,
such as references to journals, articles, or specific bibliometric
classification codes would affect the relationship between atypical
combinations and citation impact. To understand more aspects of the innovation
process, a new metric has been devised to measure to what extent researchers
are able to anticipate the changing combinatorial trends of the future. Results
show that the variant of the latter anticipation scores that is based on paper
combinations is a good predictor of future citation impact of scholarly works.
The study also shows that the effect of tested indexes vary with the
aggregation level that was used to construct them. A detailed analysis of
combinatorial novelty in the field reveals that certain sub-fields of astronomy
and astrophysics have different roles in the reconfiguration in past knowledge.
