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Highlights 1999

• Explaining the 1998 Leonid Fireball Outburst: David Asher, Vacheslav Emel'yanenko (visiting the Observatory from Chelyabinsk, Russia) and Mark Bailey explained the unexpected Leonid fireball outburst in the early hours of 17 November, which occurred more than half a day earlier than the predicted meteor shower on the night of 17/18 November 1998. The explanation for the 1998 Leonid fireball outburst attracted much scientific and public interest, and gave rise to media reports in many newspapers and magazines around the world, including The Times, Der Neue Zuercher Zeitung (Zurich), Scientific Computing World, Science News, The Boston Globe, and The Dallas Morning News.

• Predicting the 1999 Leonid Storm: David Asher also explained previous Leonid meteor storms (notably the great storms of 1833 and 1966), and together with Rob McNaught (Australian National University, Siding Spring Observatory) made accurate predictions for the times of the `normal' storm trails of the Leonids. The prediction for the 1999 storm (for November 18 02 $^{\mbox{\scriptsize h}}$ 08 $^{\mbox{\scriptsize m}}$) turned out to be `spot-on', and made headlines around the world. The success of the Asher/McNaught approach in predicting the time of the meteor storm was hailed by the editor of the International Meteor Organization¹ as equal in importance to the basic understanding of how meteors work, following the famous 1833 storm. David Asher has also computed the circumstances of the Leonid meteor showers for 2000, 2001, 2002 and 2006 (see http://www.arm.ac.uk/leonid). The 2000 event involves the Earth's first passage through the 4-revolution trail of meteoroids ejected from the comet in 1866. Observations of these meteoroids will be crucial for predicting the precise meteoroid flux in 2001 and 2002.

• Stellar Evolution Following Stellar Merger: Simon Jeffery, in collaboration with Hideyuki Saio (University of Tohoku, Japan) has developed a new evolutionary model for the pulsating helium star V652Herculis. In this model, two helium white dwarfs in a binary system coalesce. The increased mass of the new star allows nuclear burning to begin and the star becomes a giant. Its subsequent evolution provides models which match the observed properties of V652Her almost perfectly.

• Pulsation Mass for Second Helium Star: In two studies of a pulsating helium star LSS3184, which has properties very similar to V652Her, Simon Jeffery, Vincent Woolf and collaborators at the South African Astronomical Observatory have measured the radius and mass. Somewhat surprisingly, the results were somewhat smaller than expected. Since LSS3184 has a carbon-rich surface, while V652Her has a nitrogen-rich surface, this raises new questions about their possible evolutionary origin.

• Rare Earth: John Chambers, in collaboration with George Wetherill (Carnegie Institution, Washington), has made computer simulations of the origin and formation of the Earth and inner planets, yielding Earth-like planets moving on almost circular orbits, allowing them to have potentially stable climates. The fraction of planets with orbits lying entirely in the habitable or `Goldilocks zone' around other stars (neither too hot nor too cold) is very small, suggesting that living organisms as complex as those found on Earth might be of exceptionally rare occurrence in the Universe.

• Solar Influence on Climate: A new correlation between the global low cloud factor and cosmic-ray flux, found by Enric Pallé Bagó and John Butler, suggests that a substantial fraction of the global warming since the late-nineteenth century can be explained by a combination of the direct (solar luminosity change) and indirect (cosmic-ray induced change in cloudiness) effects of solar activity.

• Detection of Nano-Flares: Gerry Doyle and Luca Teriaca have interpreted red-shifted spectral lines in the solar atmosphere (temperatures 20,000-200,000K), and blue-shifted features at higher temperatures, in terms of nano-flares in a magnetic loop around the OVI formation temperature.

• Honorary Professorship: Gerry Doyle was awarded an Honorary Professorship from QUB, starting 1999 June 1.

• Minor Planet for DENI: The asteroid (9140)Deni was formally announced by the International Astronomical Union Minor Planet Center on 1999 April 2 (ref. MPC 34351). The citation reads:

  ``(9140)Deni = 4195 T-3.
  Discovered 1977 October 16 by C.J. van Houten and I. van Houten-Groeneveld on Palomar Schmidt plates taken by T. Gehrels. Named after the Department of Education for Northern Ireland for its support of the Armagh Observatory, where Ernst Öpik carried out seminal work on the collisional evolution and dynamics of small bodies. The DENI has promoted lifelong learning and research across many disciplines, encompassing higher education, schools, museums, recreation and culture. It has sought for many years to advance knowledge and understanding of the natural world, and to provide the means by which as many people as possible may appreciate and continue to develop Northern Ireland's rich cultural heritage, its diversity and contributions to the scientific, intellectual and social life of the community.''

• Centre Stage in Dublin: A fictional account of the life of Robert Hogg, assistant astronomer at Armagh Observatory in the 1790s and early 1800s, provided the inspiration for Darragh Carville's Gothic Sci-Fi thriller ``Observatory'', which was shown at the The Peacock Theatre Dublin, during April 1999.

• Media Coverage: The Observatory is one of the principal points of contact for astronomy in both Northern Ireland and the Republic of Ireland, receiving many public enquiries and citations in the national and international press, and on radio and television. During 1999, the Observatory was noted in one or another such medium at least 233 times. These identified media mentions, which are a subset of the whole, are listed in Appendix F.

• External Grant Income: Total external grant income during the financial year 1999/2000 was £293k, an increase on the previous year and a significant fraction (65%) of the total DCAL recurrent grant-in-aid (£452k). Total external income (excluding £125k in kind through the Joint Research Equipment Initiative) was £305k.