Tennessee State University
Center of Excellence in Information Systems
Nashville, Tennessee 37209

This report covers the interval October 1, 2004, through September 30, 2005.

The astrophysics program in the TSU Center of Excellence concentrates on photometry and spectroscopy of cool giants, chromospherically active stars, solar-type stars, planetary-candidate host stars, binary and multiple stars, and pulsating variables, as well as building and managing robotic telescopes and applying automation to astronomy. Astronomy staff in 2004-05 were Geoffrey S. Burks, Michael R. Busby, Joel A. Eaton, Francis C. Fekel, Gregory W. Henry, and Michael H. Williamson. Student research assistants were Rita Barley, Felisia Exum, Janine Felix, Stephen Henry, Julie Henry, Daniel Henry, David Hill, Shona Paul, and Maysam Sarfaraz. Most were involved in the JPL Summer Navigator Project. Stephen Henry, a long-time student research assistant, left in July to begin graduate school in mathematics at Clemson University. He received Clemson's University Distinguished Scholar award.

During the summer of 2005, the offices of the Center of Excellence were moved from the Avon Williams building in downtown Nashville to TSU's main campus on John A. Merritt Boulevard. The Center is temporarily located on the third floor of Holland Hall but will be relocated nearby into a new research building upon its completion.

OBSERVING FACILITIES

Center of Excellence astronomers operate several automatic telescopes at Fairborn Observatory in the Patagonia mountains of southern Arizona. Fairborn is a non-profit Educational Corporation directed by Lou Boyd and dedicated to the advancement of automated astronomy. Operational telescopes include the T2 0.25 m automatic photoelectric telescope (APT) for Johnson VRI photometry, the T3 0.40 m APT for Johnson BV photometry, the T4 0.75 m APT for Stromgren by photometry, the T8, T10, T11, and T12 0.80 m APTs, also for Stromgren by photometry, and the T13 2.0 m automatic spectroscopic telescope (AST) for high-resolution echelle spectroscopy.

During the most recent observing year (2004 September - 2005 July), the T2 0.25 m APT collected 7914 group observations during 243 nights, mostly of the unusual Be variable star gamma Cas. In 17 years of operation, the T2 APT has collected 110,572 group observations of variable stars. The T3 0.40 m APT collected 14,981 group observations, primarily of chromospherically active single and binary stars and gamma Doradus candidates, on 239 nights. In its 18 years of operation, it has collected 245,959 group observations. The T4 0.75 m APT acquired 6,702 group observations of solar-type stars on 234 nights. It has collected a total of 77,374 group observations in 13 years of operation. The T8 0.80 m APT made 9952 group observations of solar-type stars on 236 nights. In 10 years of operation, it has collected a total of 71,910 group observations. The T10 0.80 m APT made a total of 9500 group observations of solar-type stars on 239 nights. In 5 years of operation, it has collected a total of 47,035 group observations. The T11 0.80 m APT made a total of 9724 group observations of solar-type stars on 238 nights. In 5 years of operation, it has collected a total of 45,129 group observations. The T12 0.80 m APT made a total of 11,774 group observations of planetary candidate stars on 241 nights. In its 5 years of operation, it has collected a total of 49,027 group observations. Finally, the T13 2.0 m AST collected 9857 high-dispersion echelle spectra on 266 nights; it has acquired at total of 19,069 spectra in its first 2 full years of operation. Further information about the APTs and the AST can be found on the Web at http://schwab.tsuniv.edu and http://astro.tsuniv.edu, respectively.

In 2005 January, Henry, acting as PI, along with CoI's P. Butler and M. Lopez-Morales (Carnegie Instituion of Washington), proposed to the National Science Foundation (NSF) Major Research Instrumention (MRI) program for funds to construct three new 0.8 m APTs to expand the Center's planetary search program. The proposal was fully funded, and Boyd at Fairborn Observatory will build the telescopes, which will be similar to the existing T10, T11, and T12 APTs including their two-channel Stromgren by photometers. One of the telescopes will remain at Fairborn, while two will be installed in a new automated enclosure at Carnegie's Las Campanas Observatory in Chile. We expect it to take 2 - 3 years to bring these new telescopes into operation.

RESEARCH

Automatic Telescopes

Eaton and Williamson continue to manage operations of the TSU 2.0 m Automatic Spectroscopic Telescope (AST). They have determined roughly the quality of radial velocities of cool giant stars measured with this instrument as 0.10 km/s RMS for sharp-lined stars and 0.2 km/s RMS for broad-lined stars, with a systematic error of the velocity scale of -0.36 km/s with respect to IAU velocity standards.

Binary and Multiple Stars

Fekel, in collaboration with C. Scarfe (Univ. of Victoria) and others, is continuing spectroscopic observation of about 20 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 USNO observers.

Fekel and Tomkin (Univ. of Texas) are obtaining spectra of about 40 known spectroscopic binaries with orbital periods greater than 5 days. Such stars are likely targets of various optical interferometers that are now in operation. The new radial velocities will be used to determine significantly improved orbital elements so that good three-dimensional orbital solutions can eventually be determined. For seven single-lined binaries, lines of the secondary star have been detected, turning those systems into the more useful double-lined variety. Almost complete is the initial paper in this series. Spectroscopic results are discussed for three eccentric binaries with periods near 10 days: RR Lyn, 12 Boo, and HR 6169. The observations are precise enough to determine component minimum masses to better than 1%. RR Lyn is an eclipsing binary, so improved masses have been determined for this system. The binary 12 Boo already has a combined spectroscopic-visual orbital solution. The new spectroscopic orbit is in excellent accord with that solution and improves the precision of the masses. For HR 6169 the new orbit significantly revises the minimum masses of the binary components.

Fekel has placed some of the 40 possible interferometric binaries on the TSU 2.0 m AST observing program. From an examination of IAU radial velocity standards, the velocity precision of the red-wavelength echelle spectra (resolving power = 32,000) from this telescope is quite good, about 0.2 - 0.3 km/s. Unfortunately, the best signal-to-noise ratio currently attainable for a single spectrum is about 150, inadaquate to detect the secondary in many of the program stars.

Fekel, in collaboration with K. Hinkle (NOAO), R. Joyce (NOAO) and P. Wood (Australian National Univ.), has continued a program of high-resolution infrared spectroscopy to obtain orbital elements of over 50 southern symbiotic binaries. This survey will greatly supplement recent results for 15 systems observed in a northern hemisphere program. Since currently there are less than two dozen symbiotic systems with well-determined orbital elements, the results from this observing program will provide statistics on a greatly expanded sample of symbiotic binaries. To date, the observations indicate that the vast majority of southern symbiotics have orbital periods of at least 500 days. The destruction of Mt. Stromlo Observatory in 2003 has greatly slowed the project since no suitable southern telescope has been found to continue this extensive long-term program. Many southern symbiotic stars north of -40 degrees in declination are being observed at a wavelength of 1.01 microns with the Kitt Peak National Observatory coude feed telescope. A few additional infrared spectra have been obtained at the Gemini South telescope in Chile.

Fekel, Hinkle, Joyce, V. Smith (NOAO), Wood, and T. Lebzelter (Univ. of Vienna) have finished work on V2116 Oph, a very unusual symbiotic binary consisting of an M giant plus a neutron star in an orbit with a period of 1161 days. The orbital period is about two orders of magnitude longer than any other known X-ray binary. The M giant has a mass of less than 1.22 solar masses, making it a low-mass object. Its radius of 103 solar radii is much less than the size of its Roche lobe, so mass is being transfered to the neutron star via a stellar wind. The M giant has near solar abundances, a property that is at odds with its very large systemic velocity of -177 km/s since that velocity implies that the system should be a metal-poor halo star. Instead the system may have been given a runaway velocity by the supernova explosion. The properties of the giant indicate that it is at the tip of the first-ascent red-giant branch. Despite its low mass, many of the above properties of the giant star and the system in general are not consistent with those of low-mass X-ray binaries, indicating that V2116 Oph almost certainly has had a rather unusual evolutionary history.

Fekel and Henry have determined an improved orbit for HD 149420. It consists of A9 IV and F5 V stars with a period of 3.3943 days. Ground based photometry confirms the ellipsoidal light variations first found in the Hipparcos satellite results, but Fekel and Henry also discovered short-period light variations attributed to delta Scuti type pulsations. Analysis of the light curve indicates the possibility of extremely shallow grazing eclipses.

Henry and Fekel with J. Sowell (Georgia Tech Univ.) and J. Gearhart (Georgia Tech Univ.) have obtained and analyzed photometry and spectroscopy of HD 71636. This system is a detached eclipsing binary with a period of 5.013 days that consists of two F-type stars on the main sequence.

Chromospherically Active Stars

Eaton and several collaborators used AST and additional spectra to detect the secondary component of IM Peg, the guide star for the Gravity Probe B space mission. Results have been submitted for publication in the Astrophysical Journal.

Fekel and Henry have continued their work on chromospherically active stars. Fekel and Henry (2005) analyzed spectroscopy and photometry of three single-lined K-giant binaries, HD 37824, HD 181809, and HD 217188, determining improved orbits and examining the photometric variability of the giants. Rotation periods were determined for all three giants from their photometric variability. Only HD 37824 was synchronously rotating. All three giants show long-term variations in mean brightness and photometric amplitude, but no correlations were found between seasonal mean brightness, photometric amplitude, and seasonal photometric period in any of the stars. Two of the systems likely contain first-ascent giants, while the giant in HD 37824 appears to be in the core helium-burning phase of its evolution.

With TSU undergratudate Ceteka Lewis, Fekel, Henry, and Lewis (2005) obtained new spectroscopic and photometric observations of HD 144110. They determined an improved orbit and some basic properties of this double-lined, solar-type, chromospherically active binary system. The photometric observations indicate that the rotation of the two components of HD 144110 is synchronous with the 1.671 day orbital period. Despite such a short period, no eclipses were seen in the photometry.

Extrasolar Planets

Henry is continuing to make photometric brightness measurements of planetary candidate host stars to search for additional planetary transits of bright stars and to confirm new planetary candidates, primarily in collaboration with the California and Carnegie planet-search group led by G. Marcy (Univ. of California) and P. Butler (Carnegie Institution of Washington). In Rivera et al. (2005), this team announced the lowest-mass planet yet detected by radial velocity techniques, a ~7.5 earth mass planet in a 1.9379 day orbit around the M4 V star GJ 876, which is now known to host three planets. The brightness measurements from Fairborn Observervatory confirm low-level brightness variability in GJ 876 and provide the first explicit determination of the star's 96.7 day rotation period. However, additional photometry from Las Campanas observatory failed to find transits of the 1.9 day planet.

Henry continues to work with N2K (Next 2000 Stars) Consortium. This group consists of the California planet-search group and additional researchers from the Space Telescope Science Institute, Japan, and Chile. The N2K Consortium is using the Keck, Magellan, and Subaru telescopes to search for short-period gas giant planets around a new sample of 2000 F - M metal-rich main sequence and subgiant stars brighter than V = 10.5. The goal is to find several new short-period planets that transit host stars bright enough to do detailed follow up observations both from the ground and from space. In the Consortium's second paper (Sato et al. 2005), a Saturn-mass planet was found in a 2.8766 day orbit around the G0 IV star HD 149026 (V = 8.15). Photometric observations with the APTs revealed transit events with depths of only 0.003 mag at the predicted times of conjunction. Fitting of the transit data showed the planet to have a radius of 0.725 Jupiter radii. Models for this planet suggest the presence of a very large core of 60 - 70 earth masses composed of elements heavier than hydrogen and helium. The existence of this planet reveals the great diversity of extrasolar planet properties. In particular, this new find challenges models of planetary formation.

Gamma Doradus Stars

Henry and Fekel are continuing their photometric and spectroscopic studies of candidate gamma Doradus stars primarily with the T3 APT and the KPNO coude feed telescope. With their study of eleven candidate gamma Doradus stars published in the 2005 June issue of the Astronomical Journal, the total number of confirmed gamma Doradus stars is 54. Their spectroscopic and photometric work has proven the gamma Doradus nature of the majority of stars in this class.

Henry, Fekel, and S. Henry (Clemson Univ.) are preparing a new paper confirming approximately 10 additional gamma Doradus variables. The candidates were chosen both from the lists of G. Handler (Univ. of Vienna) and from lists of variable comparison stars found with the various APTs. These results will further increase the list of confirmed gamma Doradus stars by ~20%.

Henry conducted a photometric survey of 275 gamma Doradus candidates several years ago (2001-02) with the T12 APT. The primary sample of candidates (114 stars) was extracted from the Hipparcos Catalog as a complete volume-limited sample of stars lying within the gamma Doradus instability strip of the H-R diagram. Another secondary sample (161 stars) was also extracted from the Hipparcos Catalog from field stars lying in a somewhat larger region of the H-R diagram. The one year survey consisted of acquiring one group observation of each star per night throughout each star's observing season. Henry found 39 variables (or 34%) in the primary sample and 36 variables (22%) in the secondary sample.

Henry and Fekel are making additional more intensive photometric and spectroscopic observations of the 39 variable stars from the primary survey sample, again using the T3 APT and KPNO coude telescopes. Half of the sample was reobserved photometrically with the T3 APT this year (2004-05) and the rest will be observed in 2005-06. Fekel is making spectroscopic observations to obtain radial velocities and other stellar properties. S. Henry in performing the photometric variability analysis. This study will provide the first measurement of the incidence of gamma Doradus variability and further refine the position of the gamma Doradus instability strip.

Solar-Type Stars

Henry's program of long-term study of photometric variations in a large sample of solar-type stars is ongoing. The T3, T4, and T8 stellar sub-samples have now been observed for 8 to 13 years, while the stars on T10 and T11 have been monitored for four or five years. Collaborations are continuing on several aspects of this program with J. Hall and G. W. Lockwood (Lowell Observatory), R. Radick (Air Force Research Laboratory), S. Baliunas (CfA), K. Biazzo and her collaborators (Univ. of Catania), and G. Marcy and J. Wright (Berkeley). Several papers in this area are in preparation.

Miscellaneous

For 15 years 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. The 10 stars with the most constant velocities are HR 153, HR 675, HR 1389, HR 2010, HR 2489, HR 3383, HR 5447, HR 7512, HR 7773, and HR 8404.

PUBLICATIONS

Aarum-Ulvas, V. & Henry, G. W. 2005, "Modelling the Colour-Brightness Relation of Chromospherically Active Stars," Astronomische Nachrichten, 326, 292

Buggs, C., Onouha, G., Smith, B., Burks, G. S., & Fekel, F. C. 2004, "HR 1613, A Short-Period Spectroscopic Binary," BAAS, 36, 1526

Burks, G. S. & Smith, W. 2004, "The TSU Streaming Video Astronomy Course II, Video Interface Design and Bandwidth Considerations," BAAS, 36, 1500

Butler, R. P., Vogt, S. S., Marcy, G. W., Fischer, D. A., Wright, J. A., Henry, G. W., Laughlin, G., & Lissauer, J. J. 2004, "A Neptune-Mass Planet Orbiting the Nearby M Dwarf GJ 436," ApJ, 617, 580

Fekel, F. C., Barlow, D. J., Scarfe, C. D., Jancart, S., & Pourbaix, D. 2005, "HD 166181 = V815 Herculis, A Single-Lined Spectroscopic Multiple System," AJ, 129, 1001

Fekel, F. C. & Henry, G. W. 2005, "Chromospherically Active Stars. XXIV. The Giant, Single-lined Binaries HD 37824, HD 181809, and HD 217188," AJ, 129, 1669

Fekel, F. C., Henry, G. W., Baliunas, S. L., & Donahue, R. A. 2004, "Variability in a Large Sample of Sun-like Stars," in Stars as Suns: Activity, Evolution, and Planets, IAU Symposium Vol. 219, eds. A. K. Dupree & E. O. Benz (San Francisco: ASP), p. 269

Fekel, F. C., Henry, G. W., & Lewis, C. 2005, "Chromospherically Active Stars. XXV. HD 144110, A Double-lined K Dwarf Binary," AJ, 130, 794

Fekel, F. C., Hinkle, K. H., & Joyce, R. R. 2004, "Rotational Velocities of S-Type Symbiotic Stars," in Stellar Rotation, Proceedings of IAU Symposium No. 215, eds. A. M. Maeder & P. Eenens (San Francisco: ASP), p. 168

Fekel, F. C., Warner, P. B.,& Kaye, A. B. 2004, "Rotational Velocities of B, A, and Early-F Stars," in Stellar Rotation, Proceedings of IAU Symposium No. 215, eds. A. M. Maeder & P. Eenens (San Francisco: ASP), p. 53

Fischer, D. A., Laughlin, G., Butler, P., Marcy, G., Johnson, J., & Henry, G. et al. 2005, "The N2K Consortium. I. A Hot Saturn Planet Orbiting HD 88133," ApJ, 620, 481

Gillman, A., Henry, S. M., & Henry, G. W. 2004, "A Search for Transiting Hot Neptunes in High-Precision Photometry of Solar-Type Stars," BAAS, 36, 1567

Henry, G. W. & Fekel, F. C. 2005, "HD 8801 = HR 418: A Unique Single Am Star with gamma Doradus and delta Scuti Pulsations," AJ, 129, 2026

Henry, G. W., Fekel, F. C., & Henry, S. M. 2005, "Eleven New gamma Doradus Stars," AJ, 129, 2815

Lebzelter, T., Hinkle, K. H., Wood, P. R. Joyce, R. R., & Fekel, F. C. 2005, "A Study of Bright Southern LPVs," A&A, 431, 623

Lebzelter, T., Wood, P. R., Hinkle, K. H., Joyce, R. R., & Fekel, F. C. 2005, "AGB Pulsation in the Globular Cluster 47 Tuc: Radial Velocity Variations," A&A, 432, 207

Marcy, G. W., Butler, R. P., Vogt, S. S., Fischer, D. A., Henry, G. W., Laughlin, G., Wright, J. T., & Johnson, J. A. 2005, "Five New Extrasolar Planets," ApJ, 619, 570

Radick, R. R., Lockwood, G. W., Henry, G. W., & Baliunas, S. L. 2004, "The Variability of Sunlike Stars on Decadal Timescales," in Stars as Suns: Activity, Evolution, and Planets, IAU Symposium Vol. 219, eds. A. K. Dupree & E. O. Benz (San Francisco: ASP), p. 264

Rivera, E. J., Lissauer, J. J., Butler, R. P., Marcy, G. W., Vogt, S. S., Fischer, D. A., Brown, T. M., Laughlin, G., & Henry, G. W. 2005, "A ~7.5 Earth-Mass Planet Orbiting the Nearby Star, GJ 876," ApJ, 634, 625

Sato, B., Fischer, D. A., Henry, G. W., et al. 2005, "The N2K Consortium. II. A Transiting Hot Saturn Around HD 149026 with a Large Dense Core," ApJ, 633, 465

Vogt, S. S., Butler, R. P., Marcy, G. W., Fischer, D. A., Henry, G. W., Laughlin, G., Wright, J. T., & Johnson, J. A. 2005, "Five New Multi-Component Planetary Systems," ApJ, 632, 638

Welsh, W. F., Orosz, J. A., Wittenmyer, R. A., Schultz, A. B., Kinzel, W., Kochte, M., Henry, G., Bruhweiler, F., and Bennum, D. 2005, "Modelling the Transits of HD 209458b," in Extrasolar Planets: Today and Tomorrow, ASP Conf. Ser. 321, eds. Beaulieu, J.-P., Lecavelier des Etangs, A., & Terquem, C. (San Francisco: ASP), p. 213

Wittenmyer, R. A., Welsh, W. F., Orosz, J. A., Schultz, A. B., Kinzel, W., Kochte, M., Bruhweiler, F., Bennum, D., & Henry, G. 2005, "The Orbital Ephemeris of HD 209458b," in Extrasolar Planets: Today and Tomorrow, ASP Conf. Ser. 321, eds. Beaulieu, J.-P., Lecavelier des Etangs, A., & Terquem, C. (San Francisco: ASP), p. 215

Wittenmyer, R. A., Welsh, W. F., Orosz, J. A., Schultz, A. B., Kinzel, W., Kochte, M., Bruhweiler, F., Bennum, D., Henry, G. W., Marcy, G. W., Fischer, D. A., Butler, R. P., & Vogt, S. S. 2005, "System Parameters of the Transiting Extrasolar Planet HD 209458b, ApJ 632, 1157