We update our prior work on the case B collisional-recombination spectrum of He i to incorporate ab initio photoionization cross-sections. This large set of accurate, self-consistent cross-sections represents a significant improvement in He i emissivity calculations because it largely obviates the piecemeal nature that has marked all modern works. A second, more recent set of ab initio cross-sections is also available, but we show that those are less consistent with bound-bound transition probabilities than our adopted set. We compare our new effective recombination coefficients with our prior work and our new emissivities with those by other researchers, and we conclude with brief remarks on the effects of the present work on the He i error budget. Our calculations cover temperatures 5000 ≤ Te 25 000 K and densities 101ne ≤ 1014 cm−3. Full results are available online (see Supporting Information).

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Published in Monthly Notices Letters of the Royal Astronomical Society, v. 425, no. 1, p. L28-L31.

This article has been accepted for publication in Monthly Notices Letters of the Royal Astronomical Society ©: 2012 The Authors. Published by Oxford University Press on behalf of the Royal Astronomical Society. All rights reserved.

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The authors thank the University of Kentucky Center of Computational Sciences for a generous allotment of computer time. GJF acknowledges support by NSF (0908877, 1108928 and 1109061), NASA (07-ATFP07-0124, 10- ATP10-0053 and 10-ADAP10-0073), JPL (RSA no. 1430426) and STScI (HST-AR-12125.01, GO-12560 and HST-GO-12309).

Related Content

Erratum: 'Improved He I emissivities in the Case B approximation'. Published in Monthly Notices Letters of the Royal Astronomical Society, v. 433, no. 1, p. L89-L90, DOI: http://dx.doi.org/10.1093/mnrasl/slt049. Click here to access article in UKnowledge.

MNL2_1300_sm_suppmatT1.txt (130 kB)
Supplementary File 1

MNL2_1300_sm.txt (1 kB)
Supplementary File 2