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We report our analysis of the stability of pulsation periods in the DAV star (pulsating hydrogen atmosphere white dwarf) ZZ Ceti, also called R548. On the basis of observations that span 31 years, we conclude that the period 213.13 s observed in ZZ Ceti drifts at a rate dP/dt 5 (5.5 plus or minus 1.9) x 10(exp -15) ss(sup -1), after correcting for proper motion. Our results are consistent with previous P values for this mode and an improvement over them because of the larger time base. The characteristic stability timescale implied for the pulsation period is |P||P(raised dot)|greater than or equal to 1.2 Gyr, comparable to the theoretical cooling timescale for the star. Our current stability limit for the period 213.13 s is only slightly less than the present measurement for another DAV, G117-B15A, for the period 215.2 s, establishing this mode in ZZ Ceti as the second most stable optical clock known, comparable to atomic clocks and more stable than most pulsars. Constraining the cooling rate of ZZ Ceti aids theoretical evolutionary models and white dwarf cosmochronology. The drift rate of this clock is small enough that we can set interesting limits on reflex motion due to planetary companions.

As the WET moves to CCD systems, we move away from the uniformity of the standard WET photometer into an arena where each system can be radically different. There are many possible CCD photometry systems that can fulfil the requirements of a WET instrument, but each of these will have their own unique native data format. During XCov22, it became readily apparent that the WET requires a defined data format for all CCD data that arrives at HQ. This paper describes the proposed format for the next generation of WET data; the final version will be the default format for XQED, the new photometry package discussed elsewhere in these proceedings.

For many years, the Whole Earth Telescope has used the QED software package, created by R. E. Nather, to reduce the data gathered from the WET standard, PMT based photometers. While essential for reducing this data, QED alone is not a sufficient package for reducing CCD photometry data, which is becoming a larger fraction of WET data. In addition, QED requires DOS, while many astronomers, and WET HQ, do everything in a different environment (usually Unix based). A new version of the data reduction software will allow the WET to continue to operate with future CCD photometers and systems, and to reduce archival photometry data with new computer systems. Here a software package is described which will satisfy these new needs.

We report on the 323 hours of nearly uninterrupted time series photometric observations of the DBV star GD 358 acquired with the Whole Earth Telescope (WET) during May 23 to June 8, 2000. We acquired more than 232 000 independent measurements and detected the non-radial g-modes consistent with degree ℓ = 1 and radial order 8 to 20 and their linear combinations up to 6th order. We also detect, for the first time, a high amplitude ℓ = 2 mode, with a period of 796 s. In the 2000 WET data, the largest amplitude modes are similar to those detected with the WET observations of 1990 and 1994, but the highest combination order previously detected was 4th order.

We present the first spectroscopic orbit for the massive X-ray binary LS 5039, which we find to be a short-period (P = 4.117 ± 0.011 days) and highly eccentric (e = 0.41 ± 0.05) system. The low-mass function for the orbit appears to be most consistent with a neutron star companion, although a black hole remains a possibility if the system has a low inclination. The spectrum of the O7 V optical star appears to be normal for its type (suggesting that there is little flux in the red from an accretion disk) except that the C IV λλ5801, 5812 lines are very weak, perhaps indicating the presence of CNO-processed gas in the O star. There is no evidence of Hα emission, so the system is probably not currently undergoing Roche lobe overflow. The projected rotational velocity, V sin i = 131 ± 6 km s-1, suggests that the optical star is rotating faster than synchronously with the orbit. The peculiar component of the systemic radial velocity is -17 ± 3 km s-1, so the system is not a runaway star (at least not in this dimension).

The star ι Ori (HD 37043, HR 1899) is a 29.1338 day period, double-lined O-type spectroscopic binary with a highly eccentric orbit. The classification of the primary (O9 III) is well established. The secondary, roughly 2 mag fainter, is generally acknowledged as an early-type B star, but claims about its luminosity class have been made only from its estimated light contribution and not from its spectrum. We have collected visual data with the 1 m Multiple-Telescope Telescope (MTT; at the Center for High Angular Resolution at Georgia State University) in four wave bands well distributed in orbital phase, with the periastron passage particularly well covered. We present reconstructed component spectra from our tomographic reconstruction technique. According to three Morgan-Keenan (MK) luminosity criteria, we can unambiguously characterize the secondary as a B1 III-IV giant (MK type or B0.8 III-IV interpolated type). We also have constructed three line-strength indices from eighteen observed individual lines for the secondary and a grid of comparison stars. These results confirm the typing from the MK luminosity criteria. Furthermore, we argue, from the mass ratio (q = 0.5), evolutionary considerations, the orbital scale, and the unremarkable CNO element equivalent widths of the secondary, that this system is not coevolved nor has it undergone significant mass transfer. We postulate an origin for the system in a binary-binary collision and suspect that the runaway stars μ Col and AE Aur may have been the original partners for the current ι Ori secondary and primary, respectively.

We present new radial velocity data for the massive binary HD 199579 O6 V((f)) based upon spectra obtained from IUE, the Canada-France-Hawaii Telescope, KPNO, the David Dunlap Observatory, and the GSU Multiple-Telescope Telescope. We derive a revised period, P = 48.5216 ± 0.0015 days, and improved orbital elements that agree with the earlier elements within their errors. We applied a Doppler tomography algorithm to the KPNO spectra to reconstruct the individual primary and secondary spectra in the red, yielding the first detection of the secondary's spectrum. The spectral features observed, implied mass ratio (M2/M1 = 4 ± 1), and magnitude difference (▵V = 2.5 ± 0.3) are all consistent with a secondary of type B1 V - B2 V. The maximum angular separation of the components is predicted to be ≈1.2 mas, and thus the binary is an important target for optical interferometry.

The "Struve-Sahade effect" (S-S effect) is the apparent weakness of lines of the secondary in massive binaries when the secondary is receding. This effect poses problems for the accurate reconstruction of the separated primary and secondary spectra. We have reexamined IUE spectra of three classical, hot binaries studied by D. Stickland in 1997. From various cross-correlation and tomographic techniques we find different results for each of the three systems. For HD 1337 (AO Cas), we find a slight S-S effect which can be explained by a mechanism of localized heating by the colliding stellar winds, as proposed by Gies, Bagnuolo, & Penny in 1997. For HD 47129 (Plaskett's star), no consistent S-S effect was found, and none is expected based on the wind heating model because the secondary has a slightly stronger wind. Finally, for HD 57060 (29 UW CMa), a strong S-S effect was found during the receding phases (0.13-0.63). In addition, we find a strong feature near phase 0.2, similar to the secondary in spectral type but shifted by ≈-400 km s-1. We explain this by absorption and reemission by strong winds wrapping around the secondary. Thus, in general, we find that the S-S effect may arise from several distinct mechanisms.

The rapid variable star, v Per (B0.5 IVIII), displays the largest amplitude pro—le —uctuations known among the growing number of massive, spectrum-variable stars. Here we present an analysis of a contin- uous 5 day run of IUE UV spectroscopy, and we show for the —rst time that the systematic, blue-to-red moving patterns observed in high-quality optical spectra are also present in the UV photospheric lines. We present cross-correlation functions of the individual spectra with that of a narrow-lined standard that produce a high signal-to-noise ratio representation of the blue-to-red moving bump patterns found in individual lines. We then use time series analysis methods to determine the periodic components of the pro—le variations (after reregistering the spectra to correct for binary motion). There are at least six periods present (ranging from 8.46 to 2.27 hr), and most of these signals are also found in optical line variations observed in 1986 (although the relative amplitudes have changed signi—cantly). Furthermore, analysis of a shorter time series of IUE spectra from 1984 shows that similar periods were present then. We also present Ha and He I j6678 pro—les obtained with the Georgia State University Multi-Telescope Telescope, which were made simultaneously with IUE, and we show that the pro—le variations are essen- tially identical in the UV and optical ranges. We rule out rotational modulation and circumstellar gas obscuration as possible causes, and we suggest instead that the variations are the result of photospheric nonradial pulsations of relatively low degree (l \ 3¨5). There were signi—cant changes (D10%) in the equivalent widths of the UV stellar wind lines during the IUE run, and we suggest that wind strength- ening events are related to episodes of large-amplitude, constructive interference between the NRP modes. Thus, intermode beating may play an important role in promoting wind loss from massive stars. Subject headings: binaries: spectroscopicstars: early-typestars: individual (v Persei) ¨ stars: oscillationsstars: winds, out—owsultraviolet: stars

We present moderate-resolution spectra obtained with the Georgia State University Multi-Telescope Telescope of 55 UMa, a triple system consisting of a 2.55 day spectroscopic binary and a third star in a 1873 day orbit (detected by speckle interferometry). We observed the spectral lines of all three stars, and we present radial velocity curves for both the close and wide orbits. We also present new speckle interferometric measurements and a revised solution of the astrometric (wide) orbit. The spectrum of each star was reconstructed using Doppler tomography, and we measured ratios of Fe I and Fe II lines in both the reconstructions and model synthetic spectra to estimate the stellar effective temperatures. These temperatures correspond to spectral types of A1 V and A2 V for the close pair and A1 V for the distant third star. We show that the metallic lines of the close pair are systematically strong, and we suggest that both objects are moderate Am stars. All the components have masses close to 2 M☉, and continued spectroscopic and astrometric observations will yield precise masses and absolute magnitudes.

A unique telescope dedicated to spectroscopy is discussed. This instrument, the Multiple Telescope Telescope, uses many novel approaches to achieve high quality, medium to high resolution spectroscopy at low cost.

HR 1217 is one of the best-studied rapidly oscillating Ap (roAp) stars, with a frequency spectrum of alternating even- and odd-� modes that are distorted by the presence of a strong, global magnetic field. Several recent theoretical studies have found that within the observable

HR1217 is a prototypical rapidly oscillating Ap star that has presented a test to the theory of nonradial stellar pulsation. Prior observations showed a clear pattern of five modes with alternating frequency spacings of 33.3 μHz and 34.6 μHz, with a sixth mode at a problematic spacing of 50.0 μHz (which equals 1.5 × 33.3 μHz) to the highfrequency side. Asymptotic pulsation theory allowed for a frequency spacing of 34 μHz, but hipparcos observations rule out such a spacing. Theoretical calculations of magnetoacoustic modes in Ap stars by Cunha (2001) predicted that there should be a previously undetected mode 34 μHz higher than the main group, with a smaller spacing between it and the highest one. The 20th extended coverage campaign of the Whole Earth Telescope (XCov20) has discovered this frequency as predicted by Cunha (2001). Amplitude modulation of several of the pulsation modes between the 1986 and 2000 data sets has also been discovered, while important parameters for modelling the geometry of the pulsation modes have been shown to be unchanged. With stringent selection of the best data from the WET network the amplitude spectrum shows highest peaks at only 50 μmag and formal errors on the determined amplitudes are 14 μmag. Some lessons for future use of WET for the highest precision photometry on bright stars are discussed.

In this article we present the first results of about 95 hours of time-series photometry on the low gravity sdB pulsating star HS 2201+2610, obtained from a multi-site time-series campaign in September-October 2000. The temporal spectrum of HS 2201+2610 shows 3 close frequencies at 2860.9, 2824.1 and 2880.8 μHz with amplitudes of about 1 %, 0.4 % and 0.1 % respectively. Due to the small number of excited modes, a mode identification is possible in principle but not easy; no clear signatures of rotational splitting are seen.