2dF Spectroscopy of Globular Clusters in M104

We have found 56 new globular clusters in M104 from 2dF multi-fiber spectroscopy, doubling the number of confirmed clusters, and extending the spatial coverage to 50 kpc radius. We find no significant rotation in the total sample, or for subsets split by color or radius. However, there are hints that the blue clusters have a higher rotation than the red clusters, and for counter-rotation of clusters at large radius. We find a total mass of M ~ 1 × 1012M⊙ and a (M/L)B =30 out to 50 kpc radius, which is strong evidence for a dark matter halo in M104.

Physics of Solar-Like Oscillations

The physics of solar and stellar oscillations determine their observable characteristics. I provide a brief overview of the properties of solar-like oscillations, excited by stochastic processes, in other stars. In addition, I consider the current state of investigations of such oscillations, as well as the prospects for an improved understanding of their physics and the properties of the pulsating stars.

The Deuterium Balmer Series

The first detection and identification of deuterium Balmer lines were recently reported in H ii regions, using high spectral resolution data secured at CFHT and VLT. The Di lines appear as faint, narrow emission features in the blue wings of the H i Balmer lines and can be distinguished from high-velocity Hi emission. The identification as deuterium and the excitation mechanism as fluorescence are both established beyond doubt. The deuterium Balmer series might lead to a new, optical method of deuterium abundance measurement in the interstellar medium. This may be the only way to observe atomic deuterium in objects like the Magellanic Clouds or low metallicity blue compact galaxies.

A Gas and Dust Rich Giant Elliptical Galaxy

The bolometric luminosity of LFIR = 2×1012 L⊙ makes ISOSS J 15079+7247 one of the most luminous and unusual galaxies detected by the 170 μm ISOPHOT Serendipity Survey (ISOSS). The detection of CO (1-0) emission identifies a giant elliptical galaxy at redshift z = 0.2136 as the counterpart of the FIR source. The derived high gas mass of 3 × 1010 M⊙ favours the picture that the dust emission is associated with this elliptical galaxy. The ultraluminous IR emission can be explained by a hidden starburst in the center of the elliptical. This is supported by the strength of non-thermal radio continuum emission. The huge dust mass of 5×108 M⊙ corresponds to a visual extinction of AV ~ 1000 mag, being consistent with the non-detection of any signatures of a strong starburst in ISOSS J 15079+7247 in optical spectra.

Pre-service Astronomy Education of Teachers

There is little research on elementary/secondary teacher preparation. Few teachers are called upon to teach astronomy specifically, or their astronomy teaching is peripheral to their main interest (e.g., general science at lower levels or physics at higher levels). Statistics indicate that large increases in student populations are expected throughout the world. “In 1997, 1.2 billion students were enrolled in schools around the world. Of these students, 668 million were in elementary-level programs, 398 million were in secondary programs, and 88 million were in higher education programs.” (Digest, 2002) These figures included large increases from the 1990 figures, e.g. 38% increase in secondary education and 68% in higher education for Africa, as opportunities to obtain an education and population both grew. (Digest, tables 395 and 412).

Cassini/Huygens Mission To Saturn: Results And Prospects

The Cassini spacecraft was launched in October, 1997. Since then it has been on an interplanetary trajectory aimed toward Saturn and arriving there on July 1, 2004. En route, Cassini has flown by Venus, the Earth, and Jupiter. Each of these events yielded new scientific results, (e.g., 11 papers in J. Geophys. Res. 106, 30099-30279.) The Cassini flyby of Jupiter, with Galileo already in Jovian orbit, enabled the first-ever simultaneous measurements by two spacecraft at an outer planet. This fortuitous event provided a unique opportunity to investigate the giant planet’s magnetic field and the properties of the Jovian system. It provided a focused period for intensive observations of Jupiter and cooperation with investigators using Galileo, Hubble, Chandra, and ground-based observatories. The results achieved at Jupiter were stunning (e.g., 8 articles in Nature 415, 965-1005, February 28, 2002). Recent results and the current status of the spacecraft and mission will be discussed. Of note are the dates of July 1, 2004 when Cassini goes into orbit about Saturn and January 14, 2005 when Huygens enters the atmosphere of Titan. The Cassini/Huygens mission is a joint undertaking by NASA and ESA, with ASI as a partner via a bilateral agreement with NASA.

New Results on the Composition of the Outer Planets and Titan

In this brief summary, I present recent progress on our knowledge of the Giant Planets and Titan atmospheric composition, as well as the impact of this progress on our understanding of Solar System formation, and atmospheric chemistry.

Radar Observations of Comet Nuclei and Comae

Nine comets have been detected with either the Arecibo (12.6 cm wavelength) or Goldstone (3.5 cm) radar systems. Included are six nucleus detections and five detections of echoes from coma grains. The radar backscatter cross sections measured for the nuclei correlate well with independent estimates of their sizes and are indicative of surface densities in the range of 0.5 to 1.0 g cm-3. Like most asteroids, comets appear to have surfaces that are very rough at scales much larger than the radar wavelength. Coma echo models can explain the radar cross sections using grain size distributions that include a substantial population of cm-sized grains. A long term goal of the cometary radar program has been the high resolution imaging of a cometary nucleus. Eleven short period comets are potentially detectable over the next two decades a few of which may be suitable for imaging. We are always waiting for the arrival of a new comet with an orbit that brings it within 0.1 AU of the earth.

Disk Chemistry and Cometary Composition

We describe a theoretical study of protoplanetary disk chemistry. By considering physical conditions similar to that of the protosolar nebula, we attempt to assess the contribution made by material from the cooler nebular regions to cometesimal composition. Calculations are presented which determine the spatial and temporal chemistry of the gas and dust within the 5-40 AU comet-forming region of the nebula. We show that there is little radial variation in the solid-state distribution of some molecules which could potentially be parents of the carbon-chain species observed in comets. We conclude that the apparent variation in abundance of C2 and C3 between long- and short-period comets is the result of chemical processing during their lifetimes and not differences in composition at the time of formation.

Nomenclature for Multiple Systems Containing Close Binaries

I would like to discuss the difficulty of developing and maintaining a hierarchical designation scheme for components of multiple systems, when components are found by more than one method. Such a sequence of discoveries can easily lead to conflict between the initial nomenclature, which gets established in the literature, and that based on a scheme that is in broader use, or is more physically representative, or both. I will describe as an example a hypothetical complex system whose hierarchical description depends on the sequence in which discoveries are made, and whose designation in discovery order is ambiguous. In the end I urge flexibility in designations.