Crosstalk: Mini Workshop on Type I X-ray bursts.

Barry Davids (TRIUMF). Experimental Efforts to Determine the 15O(a,g)19Ne Reaction Rate.
To Astronomers: The 15O(a,g) reaction rate has not been measured, but upper limits are x100 above the theoretical lower limit. With present instrumentation, we can get within x10 the theoretical lower limit; to do better, we will likely need new instrumentation, to produce a high intensity 15O beam, to produce a direct measurement. This would permit pinning down the 15O(a,g)19Ne reaction rate, which is a present choke-point in the rp-process (active in type I x-ray bursts).
To Nuclear Theorists: We need reliable theoretical predictions for reaction rates, benchmarked with observables.

Chris Ruiz (TRIUMF). Nuclear Astrophysics of neutron-deficient nuclei - experimental approaches at ISAC.
To Astrophysicists: We rely on astrophysical modellers to tell us: which reactions are of astrophysical importance? It takes many years (~5 years, say) to develop a specific reaction experimental setup, so the reactions you tell us to measure must be critically important, not merely of some curiosity.


Ed Brown (MSU/JINA). The X-ray Burst-Crust Connection.
For nuclear theorists: Pay attention to all phenomena predicted by your models. It is not enough to see that it produces consistency with one phenomenon; you must also work out the implications for other phenomena as well.


Andrew Cumming (McGill). Constraints on the rp-process from X-ray bursts.
For nuclear experimentalists: There are many possible influences on the phenomena, so nuclear reaction rates are important for understanding them, but there are astronomical influences as well. At present, our uncertainties are not hung up on a single waiting point; however, our level of uncertainty does depend, for example, on
astrophysical causes, such as turbulence or spreading in the burning layer.


Randy Cooper (Harvard/CfA). Nuclear Reactions During the Onset of Type I X-ray Bursts.
The uncertainty in the Hot CNO breakout reaction rates, and in parti15O(a,g)19Ne rate is an important uncertainty in type-I x-ray burst ignition models.

Crosstalk

Zach Medin. Condensed Matter Surfaces of Neutron Stars: Applications and Tangents.
Under certain conditions the atmosphere of a neutron star is negligibly thin and a condensed matter surface forms. This is applicable for neutron stars with large surface magnetic fields and moderate surface temperatures.
For observational astronomers: Condensed matter surfaces could be used, e.g., to explain the featureless spectrum of RX J1856.5-3754, and are also a key ingredient in vacuum gap pulsar emission models.
For nuclear theorists: The strong magnetic fields of neutron stars have an important effect on matter even at low pressure/density.