Ian Shelton

Current performance and on-going improvements of the 8.2 m Subaru Telescope

An overview of the current status of the 8.2m Subaru Telescope constructed and operated at Mauna Kea, Hawaii, by the National Astronomical Observatory of Japan is presented. The basic design concept and the verified performance of the telescope system are described. Also given are the status of the instrument package offered to the astronomical community, the status of operation, and some of the future plans. The status of the telescope reported in a number of SPIE papers as of the summer of 2002 are incorporated with some updates included as of 2004 February. However, readers are encouraged to check the most updated status of the telescope through the home page, http://subarutelescope.org/index.html, and/or the direct contact with the observatory staff.

Chemical Composition of Carbon-Rich, Very Metal-Poor Subgiant LP 625-44 Observed with the Subaru/HDS

We have obtained high-resolution (R ∼ 90000) spectra of the carbon- and s-process-element-rich, very metalpoor ([Fe/H] = −2.7) subgiant LP 625-44, as well as those of HD 140283 (a metal-poor subgiant with normal abundance ratio) for a comparison, with the High Dispersion Spectrograph (HDS) for the Subaru Telescope for detailed abundance study. The excess of oxygen in LP 625-44 seems to be remarkable (perhaps by nearly a factor 10) compared with that of HD 140283 derived from the O I triplet around 7770 u

New CCD Observations of the RR Lyrae Variables in the Oosterhoff Type IICluster M9

CCD observations have been used to study 16 of the previously known variables in the Oosterhoff type II globular cluster M9. The properties of the RR Lyrae variables in M9 are compared with those in the Oosterhoff type I cluster M3. Methods devised by Simon, Jurcsik, & Kovacs have been used to derive physical parameters for the stars from Fourier analysis. The mean metal abundance so derived for M9, [Fe/H] = -1.77, is in good agreement with the metal abundance derived from spectroscopic observations. All methods for calculating the absolute magnitudes of RR Lyrae variables from Fourier coefficients indicate that the RR Lyrae variables in M9 are more luminous than those in M3. However, there are three RR Lyrae stars in M3 that may be as bright as the M9 stars. These three are thought to be in a more advanced evolutionary state than the other M3 RR Lyrae stars. Absolute magnitudes have also been derived for the RR Lyrae stars in M68 and M107. The different methods predict that RR Lyrae stars in metal-poor clusters are more luminous than those in more metal-rich clusters, but there are inconsistencies in the relative luminosities derived by the different methods.

UBV photometry of SN 1987A - Earliest photoelectric observations

This paper reports on the earliest known photoelectric photometry for Supernova 1987A, obtained just twenty-four hours after the IMB/Kamiokande-II neutrino detection. Values of V=4.78 (±0.05), B−V=0.00 (±0.06) and U−B= −0.78 (±0.06) were measured on Feb 24,336 UT 1987. This is twelve hours sooner than the next known reliable photoelectric observation

UBVRI photometry of SN 1987A: the first 156 days from Cerro Las Campanas

This paper reports on previously unpublished UBVRI photoelectric observations of Supernova 1987A, consisting of 74 nights spanning the first 156 days of the event. The first observations come just one day after core collapse. The nightly mean magnitudes and colors have a typical error of ≤O.01 mag after transformation to the Cousins UBVRI system. Differences with respect to previously published datasets are discussed

Supernova 1987A: photometry of the discovery and pre-discovery plates

The discovery and pre-discovery plates for Supernova 1987A have been analyzed. SN 1987A was found to have B=5.00 (±0.15) on Feb 24.12 UT 1987; and Sanduleak −69° 202 was B=12.12 (±0,15) on Feb 23.08 UT 1987. These represent, respectively, the second earliest reliable photometric measure for the Supernova and the last known observation of its precursor