Bull. A. A. S., Vol. 34, 446, 2002

Tennessee State University
Center of Excellence in Information Systems
Nashville, Tennessee 37203-3401

This report covers the interval October 1, 2000, through September 30, 2001.

The astrophysics program in the Center of Excellence at TSU continues to concentrate on understanding magnetic activity in cool stars, building and managing robotic telescopes, and applying automation to astronomy. Astronomy staff in 2000-01 were Geoffrey S. Burks, Michael R. Busby, Joel A. Eaton, Francis C. Fekel, and Gregory W. Henry. Michael Williamson continued working part-time on telescope control systems and CCD controllers. Marino Alvarez (Coll. of Education), Sallie L. Baliunas (CfA), and Douglas S. Hall (Vanderbilt University) continued as adjunct staff. Mark S. Whorton (Marshall Space Flight Center) began a one year sabbatical at the Center of Excellence in August through the NASA Administrator's Fellowship Program. Fekel was named Distinguished Researcher of the Year at TSU. Keinon Brooks, Giana Galbreath, Stephen Henry, Mia Johnson, Allen Keel, Kenneth McDavis, Shannon Miles, Kevin Mixon, Fred Northern, Paul Strong, and Sean Williams served as student research assistants in the astrophysics program. S. Henry and Brooks received first and second place awards, respectively, for their student research projects presented at the 23rd Annual University-Wide Research Symposium in the spring.

1 OBSERVING FACILITIES

During the past year the astrophysics group at TSU continued making progress in achieving their dream of building and operating a completely automatic observatory affording world-class facilities for precise photometry, imaging, and high-dispersion spectroscopy. This facility is taking shape at Fairborn Observatory in southern Arizona and will consist of nine telescopes managed by TSU. The Center of Excellence has long been operating four Automatic Photometric Telescopes (APTs) at the site, including the T2 0.25 m APT for Johnson VRI photometry, the T3 0.40 m APT for Johnson BV photometry, and the T4 0.75 m and T8 0.80 m APTs for Stromgren by photometry.

After a short period of shakedown and debugging operations in 2000 September, three new 0.80 m APTs (designated T10, T11, & T12) began scientific operations in 2000 October and are performing as expected. Each is equipped with a two-channel photometer (similar to the photometer on T8) designed for simultaneous Stromgren by observations. These telescopes are being dedicated to expanding our programs to characterize the photometric changes associated with magnetic activity cycles in solar-type stars, to search for evidence of planets around other stars, and to expand our capability to observe newly emerging classes of variable stars. Further information about the APTs and their observing programs can be found on the Web at http://schwab.tsuniv.edu/.

Fairborn continues work on our 0.60 m automatic imaging telescope (AIT), for which all the physical parts are in hand, and we expect the telescope to be finished in the coming year. The primary challenge remaining in the design and construction of this instrument is building an offset guider for long exposures. This telescope will be used initially to measure the optical light variations of gamma-ray burst sources and to characterize photometric changes with magnetic activity of cool stars in clusters of various ages.

We have also continued making progress on constructing the TSU 2.0 m automatic spectroscopic telescope (AST) and verifying its safe operation. Please see our web site (http://astro.tsuniv.edu) for more details about its development. This instrument is a 2 m alt-azimuth Cassegrain telescope, fiber-coupled to a bench-mounted echelle spectrograph with three observing modes (R=30,000, 80,000, and 2500), designed for taking spectra primarily in the red (6000-7200A) and near ultraviolet (3700-4100A). The AST has now been at its site in Arizona for a year; during this time, Williamson has perfected the telescope's control system to the point of automatic observation of stars. Operating automatically, the AST has acquired stars from a list of objects to observe, centered them on a fiber feed, and tracked them steadily for times up to 20 minutes. It ran in this mode for two full nights in 2001 September, one of which had numerous interruptions for clouds that the APT handled routinely without any intervention. We have since run it automatically from Nashville. The simple tracking algorithms Williamson has developed to keep the star on the fiber feed have demonstrated the ability to get light into the fiber and keep it there. The control program selects stars to observe from a list (with priorities) on the basis of a simple ATIS-like algorithm that prefers stars in the west and discriminates against long slews. Keel and Eaton have written a simulator for the telescope that gives a good prediction of the observations it will make on a given night. Aside from some decisions about improvements in the logging to capture better quality-control data, the control system for the telescope is ready to begin routine observing.

Work on the bench-mounted spectrograph for the 2 m telescope proceeds at a reasonable pace, mostly under the management of Harland Epps. Tucson Optical Research Corporation is polishing the lenses for the spectrograph camera, although we have not yet received one of the blanks from the manufacturer. We have a contract for putting anti-reflection coatings on surfaces not oil-coupled to one another. J. Allen Schier has designed the mechanical mount for the camera lens and will oversee its construction and the assembly of the camera. We have the CCD detector (a 2Kx4K SiTE chip) set up in our lab in Nashville with a controller from SDSU and are exercising it by taking frames of a simulated starfield. We have begun assembling the optical components of the spectrograph into their stands and integrating them mechanically into the spectrograph. We have acquired most of the materials to construct the fiber feeds and have a contract for writing the software for reducing the echelle spectra. Challenges over the next year will be producing the data-handling system and integrating the software to run the spectrograph into the telescope control system, with Williamson converting the CCD control programs from an interactive system to a reliable automatic control daemon. In any case, the CCD controller is ready for testing the spectrograph in a manual mode once the spectrograph camera is finished.

Students working on telescope development and instrumentation over the past year were McDavis (telescope assembly), Williams (simulation of echelle spectra, drawings of dewar/CCD electronics packages), and Keel (telescope simulator, programs to assess logged data).

During the past year (4Q00-3Q01), the T2 0.25 m APT collected 5,695 new group observations during 227 nights, mostly of semi-regular variable stars. In its 15 years of operation, the 0.25 m APT has collected a total of 94,728 group observations. The T3 0.40 m APT collected 15,281 group observations, primarily of chromospherically active single and binary stars, on 229 nights. In its 14 years of operation, it has collected 185,979 group observations. The T4 0.75 m APT acquired 5,956 group observations of solar-type stars on 230 nights. It has collected a total of 49,613 group observtions in 9 years of operation. The T8 0.80 m APT made 6,188 group observations of solar-type stars on 225 nights. In 6 years of operation, it has collected a total of 33,809 group observations. The T10 0.80 m APT made a total of 6,998 group observations of solar-type stars with known short-period planets on 208 nights in its first year of operation. The T11 0.80 m APT made a total of 5,220 group observations of solar-type stars on 180 nights in its first year of operation. Finally, the T12 0.80 m APT made a total of 4,976 group observations, primarily of gamma Doradus candidate stars, on 153 nights in its first year of operation.

2 RESEARCH

Eaton, Henry, and S. Henry have continued investigating the random-spots model for chromospherically active stars (Eaton, Henry, & Fekel 1996, ApJ, 462, 888) by looking at the questions of preferred longitudes and spot cycles in calculations of random spots. A previous student used a two-spot model to analyze 44 sets of calculated light curves for changing distributions of random spots spanning 14 years each, representing average spot lifetimes of 2, 5, and 10 years, and constructed migration diagrams for these sets. These calculations showed the same behavior as photometry for actual stars, and they imply the real spots live something like 3 years each. Eaton has now looked for statistically significant concentrations of spots at particular stellar longitudes in these calculations, in the way L. Jetsu and others have claimed to find them in similar data for actual chromospherically active stars. He has actually found such concentrations in a significant number of cases and has looked at the question of just how one should judge whether any observed concentration of ``spots'' in longitude is really statistically significant. The random-spot calculations also show the same degree of light loss and variability seen in real stars over periods of decades, as well as the same apparently cyclical changes in their total brightness. Therefore, there is no good evidence for any phenomena in these stars, neither preferred longitudes nor spot cycles, that cannot be explained by random spots.

Eaton, Henry, and Fekel have written a paper about the advantages of automatic operation of small telescopes for a book on the future of small telescopes to be edited by T. Oswalt (FIT) and published by Kluwer Academic Publishers. They argue that such telescopes are competitive and advantageous for three reasons, namely, (1) they make possible long-term monitoring projects and research requiring data at very specific times (e.g., eclipses and other periodic phenomena; outbursts and other targets of opportunity) that would not be possible with conventional manned observatories, (2) that automatic observatories are much cheaper to operate than conventional observatories, and (3) that automatic observing actually improves the quality of observational data. They illustrate these points with examples of research from TSU's completely automatic observatory and suggest some uses for automatic telescopes in the future.

Fekel, in collaboration with C. Scarfe (Univ. of Victoria) and others, is continuing spectroscopic observation of about 25 close multiple systems and a half dozen speckle binaries to obtain fundamental parameters. For most of the systems speckle observations have been obtained by the CHARA group (Georgia State Univ.) and the USNO. Analysis of the quadruple system mu Ori has been completed. One visual component of this system consists of an Am primary and an unseen secondary, while the other visual component is a pair of F5 dwarfs. The visual orbit has a period of 18.644 years, a high eccentricity of 0.7426, and a high inclination of 96.2 degrees. The orbital parallax of 0.02107 arcseconds is more accurate than that obtained from the Hipparcos satellite and corresponds to a distance of 47.5 pc. The Am star is near the end of its main-sequence evolution.

For over a decade Fekel has monitored the radial velocities of about 30 slowly rotating B and A stars, which are candidates for early-type velocity standards. A bootstrap procedure has been used to tie the velocities of the early-type stars to the IAU late-type velocity system. Most of the early- and mid-B type stars have variable velocities. However, about two-thirds of the slowly rotating late-B and A-type stars appear to have constant velocities. In addition, Fekel has obtained rotational velocities of the stars in the sample as well as several dozen additional A-type stars and compared the v sin i values to results in the literature.

Fekel, in collaboration with K. Hinkle and R. Joyce (NOAO), has obtained numerous infrared spectra of the 1.6 micron region for nine asymptotic giant branch (AGB) field M giants that have multiple periods of light variability. Each semiregular variable has a short period of several months, which is typical of low amplitude pulsation for stars on the AGB, as well as a long period of 1 - 3 years, which is significantly longer than the predicted fundamental-mode pulsations for these variables. For six of the nine giants the radial-velocity periods are essentially the same as those of the long-period light variability. Although the possibility that the velocity variations result from orbital motion is examined, it is concluded that the long-period velocity changes in most, if not all of the nine stars, likely result from a currently unknown type of pulsation rather than duplicity.

Fekel, in collaboration with K. Hinkle and R. Joyce (NOAO) and P. Wood (Australian National Univ.), has begun a program of high-resolution infrared spectroscopy at Mt. Stromlo Observatory to obtain orbital elements of over 50 southern symbiotic binaries. This will greatly supplement their recent results for 15 northern hemisphere systems. Since currently there are less than 20 symbiotic systems with well-determined orbital elements, the results from this observing program will provide statistics on a greatly expanded sample of symbiotic binaries.

Fekel, Henry, and Brooks completed a paper for the Astronomical Journal on the single-lined, K0 IV chromospherically active binary HD 10909 = UV Fornacis. New spectroscopy and photometry demonstrated that the previously reported orbital and photometric periods are incorrect. HD 10909 has an orbital period of 30.1067 days and an eccentricity of 0.499. Its rotation period of 64.1 days is more than twice as long as its orbital period. The primary is situated near the base of the first-ascent red giant branch. Thus, its asynchronous rotation is likely the result of its recent evolution through the Hertzsprung gap, combined with its relatively long orbital period and high eccentricity.

Fekel and Henry have obtained spectroscopic and photometric observations of the single-lined binary star HD 161570. It has an orbital period of 45.623 days and a nearly circular orbit. The primary is a G7 III and mildly chromospherically active. Its light variability period varies somewhat from season to season with a representative value being 64.1 days, which is interpreted as the rotation period. Thus, the giant is not synchronously rotating. The resulting paper by Fekel, Henry, and S. Henry has been accepted for the Astronomical Journal.

Henry is continuing to study photometric variations in a sample of over 160 solar-type stars being observed with the T4 0.75 m and T8 0.80 m APTs. He and S. Henry are completing a detailed analysis of the first several years of data on these stars. It appears that there may be no significant difference in brightness variations between the Sun and this sample of solar-type stars, a result that differs significantly from previous studies of much smaller samples of stars. Fekel has obtained at least one high-resolution spectrum of each star in the sample. He has determined spectral types and v sin i values plus measured radial velocities to search for possible duplicity. A detailed paper in collaboration with Baliunas and R. Donahue (CfA) is being prepared. With the completion of the T10, T11, and T12 0.80 m APTs, Henry is increasing the sample of solar-type stars in the observing program to approximately 400. New stars are being chosen primarily from the Keck planetary-search project of G. Marcy (UC Berkeley) and the northern hemisphere survey of activity in solar-type stars by D. Soderblom (STScI).

Henry is continuing to use the APTs to search for additional planetary transits and to make other photometric observations to confirm or refute new planetary candidates. A paper was recently completed in collaboration with C. Tinney (Anglo-Australian Observatory) announcing the first results from the planet-search program on the 3.9 m Anglo-Australian Telescope. Radial velocity variations in HD 179949 were found implying a planet with a minimum mass of 0.84 M_Jup and a period of 3.09 days. The photometric observations placed a low limit on photometric variability that confirms neither starspots nor stellar pulsations can be the cause of the radial velocity variations, thus strongly supporting the existence of the planet even in the observed absence of transits. A paper in collaboration with D. Queloz (Geneva Observatory) analyzing APT photometry and Ca II H and K spectrophotometry has refuted the existence of a planet around HD 166435 and has been accepted for publication in Astronomy & Astrophysics. Henry is monitoring additional new planetary candidates in collaboration with Marcy and D. Fischer (UC Berkeley).

Henry is collaborating with A. Schultz (STScI) providing ground-based photometry of the planetary transits in HD 209458 in support of observations with the HST to monitor transits with a Fine Guidance Sensor used as a high-speed photometer. This will allow independent determination of the planet's radius and the inclination of its orbit. Several transits are being observed to determine any variability of transit times that would indicate precession of the orbit caused by secondary bodies in the HD 209458 system. The observations will also be examined for structure that would indicate the presence of planetary satellites.

Henry is observing the chromospherically active binary IM Pegasi with the T2 0.25 m and T3 0.4 m APTs in support of its selection as the guide star for NASA's Gravity Probe B mission scheduled for launch in the Fall of 2002. The observations are being evaluated by M. Ratner (CfA) in order to estimate the uncertainty in the relativity signal can be derived during the mission from observations of IM Peg with the on-board six-inch telescope.

Henry and Fekel continued their collaboration with T. Kaye (Los Alamos National Laboratory) in the study of new gamma Doradus and delta Scuti variables. A paper has been accepted for publication in the Astronomical Journal presenting high-resolution spectroscopy and precision photometry of ten new gamma Doradus and delta Scuti stars. All ten stars fall in the spectral class range F0-F2, but they are cleanly separated into two groups by their luminosities and photometric periods. Henry's photometric program on solar-type stars continues to find new variables of this type by the dozens when they are chosen as photometric comparison stars. Analysis of more of these stars is underway. Because less than 20 confirmed gamma Doradus variables are known, Henry has dedicated most of the observing time on the T12 0.80 m APT for one year to a survey of 275 gamma Doradus candiates to increase the number of known variables and to map their distribution in the H-R diagram.

Henry is continuing his collaboration with J. Percy (University of Toronto) on the analysis of many years of Johnson VRI photometry of small-amplitude, red variables observed with the T2 0.25 m APT. A paper was recently completed for the Publications of the Astronomical Society of the Pacific reporting the results of period analyses of 5000 days of photometry of 34 stars. The variations ranged from regular to irregular, but most of the stars showed periods in the range 20--200 days. A second paper to determine the modes of pulsation in these stars is in preparation.

Henry is collaborating with M. Smith (Computer Sciences Corporation) and R. Robinson (Catholic University of America) to observe the Be star gamma Cassiopeiae. Several years of Johnson BV photometry with the T3 0.75 m APT have revealed unexplained light variations of one to two percent on timescales of 50 to 90 days. These variations appear to be correlated with X-ray observations obtained with the RXTE satellite. A paper on these results is in preparation, and a proposal has been submitted for further RXTE observations to be made simultaneously with the T2 and T3 APTs.

Henry has begun a new collaboration with S. Berdyugina (University of Oulu) on the analysis of long-term light curves of chromospherically active stars obtained with the T3 0.40 m APT. A paper on active longitudes in these stars was presented at the 12th Cambridge Workshop on Cool Stars, Stellar Systems, and the Sun in Boulder, CO. Henry is also continuing a collaboration with L. Jetsu (University of Helsinki) to apply Jetsu's new time series analysis techniques to these same observations.

Burks is working to implement the Astronomy Minor that was designed last year. A full range of upper level undergraduate courses will be taught starting in the spring of 2002. Burks is also working on one of the first streaming video astronomy courses to be delivered, under a NASA NRTS grant. It is aimed primarily toward students at colleges without an astronomy course. He and Whorton are studying the use of light weight mirrors in the design of spectroscopic telescopes.

Whorton is continuing his research in active vibration control for microgravity science payloads that was begun at NASA Marshall Space Flight Center. Predictions of the International Space Station acceleration environment indicate that the ambient acceleration levels will exceed levels that can be tolerated by the science experiments. Hence, microgravity vibration isolation systems are being developed to attenuate the accelerations to acceptable levels. While passive isolation systems are beneficial in certain applications, active isolation systems are required to provide attenuation at low frequencices and to mitigate directly induced payload distrubances. Whorton is the principal investigator for a microgravity vibration isolation system called g-LIMIT, currently being developed for the Microgravity Science Glovebox and manifested for launch on the UF-2 mission in early 2002. Further information on g-LIMIT can be found at http://g-limit.msfc.nasa.gov. Whorton is also carrying out additional research in the area of fixed order robust control methods for uncertain vibration isolation systems.

PUBLICATIONS

Alvarez, M. C., Burks, G., & Henry, G. 2000, ``Explorers of the Universe: University/School Partnerships,'' in Amateur-Professional Partnerships in Astronomy, ASP Conf. Ser. 220, eds. J. R. Percy & J. B. Wilson (San Francisco: ASP), p. 341

Balachandran, S. C., Fekel, F. C., Henry, G. W., & Uitenbroek, H. 2000, ``Two K Giants with Super-meteoritic Lithium Abundances: HDE 233517 and HD 9746,'' ApJ, 542, 978

Burks, G. S., & Alvarez, M. 2000, ``Clarifying Misconceptions in College Astronomy Classes Using Concept Maps,'' BAAS, 32, 1551

Butler, R. P., Vogt, S. S., Marcy, G. W., Fischer, D. A., Henry, G. W., & Apps, K. 2000, ``Planetary Companions to the Metal-Rich Stars BD -10 3166 and HD 52265,'' ApJ, 545, 504

Fekel, F. C., & Henry, G. W. 2000, ``Chromospherically Active Stars. XVIII. Sorting Out the Variability of HD 95559 and Gliese 410 = DS Leonis,'' AJ, 120, 3265

Fekel, F. C., Henry, G. W., Brooks, K., & Hall, D. S. 2001, ``Chromospherically Active Stars. XIX. A Reexamination of the Variability of HD 10909 = UV Fornacis,'' AJ, 122, 991

Fekel, F. C., Henry, G. W., & Henry, S. M. 2001, ``Photometric Variability in G and K Giants,'' in Cool Stars, Stellar Systems, and the Sun, ASP Conf. Ser. 223, eds. R. J. Garcia-Lopez, R. Rebolo, & M. R. Zapatero Osorio (San Francisco: ASP), p. 925

Fekel, F. C., Hinkle, K. H., Joyce, R. R., & Skrutskie, M. F. 2000, ``Infrared Spectroscopy of Symbiotic Stars. II. Orbits for Five S-type Systems with Two Year Periods,'' AJ, 120, 3255

Fekel, F. C., Hinkle, K. H., Joyce, R. R., & Skrutskie, M. F. 2001, ``Infrared Spectroscopy of Symbiotic Stars. III. First Orbits for Three S-type Systems,'' AJ, 121, 2219

Grodinsky, C. M., & Whorton, M. S. 2000, ``A Survey of Active Vibration Isolation Systems for Microgravity Applications,'' Journal of Spacecraft and Rockets, 37, 586

Henry, G. W. 2000, ``Techniques for Automated Single-Star Photometry,'' in Third Workshop on Photometry, NASA/CP-2000-209614, eds. W. J. Borucki & L. E. Lasher (Langley Research Center: NASA), 25

Henry, G. W., Fekel, F. C., Henry, S. M., & Hall, D. S. 2000, ``Photometric Variability in a Sample of 187 G and K Giants,'' ApJS, 130, 201

Jetsu, L., Hackman, T., Hall, D. S., Henry, G. W., Kokko, M., & You, J., ``Time Series Analysis of V815 Herculis Photometry Between 1984 and 1998,'' A&A, 362, 223

Joyce, R. R., Hinkle, K. H., & Fekel, F. C. 2001, ``Infrared Spectroscopy of Symbiotic Stars: Orbits for Well-known S-type Systems,'' in Cool Stars, Stellar Systems, and the Sun, ASP Conf. Ser. 223, eds. R. J. Garcia-Lopez, R. Rebolo, & M. R. Zapatero Osorio (San Francisco: ASP), p. 1450

Percy, J., Bakos, A., & Henry, G. 2000, ``Long-term VRI Photometry of 89 (V441) Herculis,'' JAAVSO, 28, 164

Percy, J. R., Evans, T. D. K., Henry, G. W., & Mattei, J. A. 2001, ``Long-Term VRI Photometry of P Cygni,'' in P Cygni 2000: 400 Years of Progress, ASP Conf. Ser. 233, eds. M. de Groot & C. Sterken, p. 37

Percy, J., Kolin, D., & Henry, G. 2000, ``Long-term VRI Photometry of Rho Cassiopeiae,'' JAAVSO, 28, 164

Percy, J. R., Wilson, J. B., & Henry, G. W. 2000, ``Long-Term VRI Photometry of Pulsating Red Giants,'' BAAS, 32, 1479

Percy, J. R., Wilson, J. B., & Henry, G. W. 2001, ``Long-Term VRI Photometry of Small-Amplitude Red Variables. I. Light Curves and Periods,'' PASP, 113, 983

Tinney, C. G., Butler, R. P., Marcy, G. W., Jones, H. R. A., Penny, A. J., Vogt, S. S., Apps, K., & Henry, G. W. 2001, ``First Results from the Anglo-Australian Planet Search - A Brown Dwarf Candidate and a 51 Peg-like Planet,'' ApJ, 551, 507 Whorton, M. S. 2001, ``g-LIMIT: A Microgravity Vibration Isolation System for the International Space Station,'' AIAA 2001-5090