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Hubble Space Telescope observations of the nearby (3.22 pc), K2 V star epsilon Eridani have been combined with ground-based astrometric and radial velocity data to determine the mass of its known companion. We model the astrometric and radial velocity measurements simultaneously to obtain the parallax, proper motion, perturbation period, perturbation inclination, and perturbation size. Because of the long period of the companion, \eps b, we extend our astrometric coverage to a total of 14.94 years (including the three year span of the \HST data) by including lower-precision ground-based astrometry from the Allegheny Multichannel Astrometric Photometer. Radial velocities now span 1980.8 -- 2006.3. We obtain a perturbation period, P = 6.85 +/- 0.03 yr, semi-major axis, alpha =1.88 +/- 0.20 mas, and inclination i = 30.1 +/- 3.8 degrees. This inclination is consistent with a previously measured dust disk inclination, suggesting coplanarity. Assuming a primary mass M_* = 0.83 M_{\sun}, we obtain a companion mass M = 1.55 +/- 0.24 M_{Jup}. Given the relatively young age of epsilon Eri (~800 Myr), this accurate exoplanet mass and orbit can usefully inform future direct imaging attempts. We predict the next periastron at 2007.3 with a total separation, rho = 0.3 arcsec at position angle, p.a. = -27 degrees. Orbit orientation and geometry dictate that epsilon Eri b will appear brightest in reflected light very nearly at periastron. Radial velocities spanning over 25 years indicate an acceleration consistent with a Jupiter-mass object with a period in excess of 50 years, possibly responsible for one feature of the dust morphology, the inner cavity.

About 30.5 days of nearly uninterrupted broadband photometry of the solar-type star Kappa1 Ceti, obtained with the MOST (Microvariability & Oscillations of STars) satellite, shows evidence for two large starspots with different rotation periods of 8.9 and approximately 9.3 days (DeltaOmega/Omega~4%). Ground based measurements in 2002 and 2003 of Ca II H & K emission reveal variations in chromospheric activity with a period of about 9.3 days. The data were obtained during the MOST commissioning phase. When the data are combined with historical observations, they indicate that the 9.3-day spot has been stable in its period for over 30 years. The photometry, with a sampling rate of approximately once per minute, was also used to search for acoustic (p-mode) oscillations in the star. We detect no clear evidence for p-modes in the Kappa1 Ceti photometry, with a noise level around 7-9 mu_mag at frequencies in the range 0.5-4 mHz (3-sigma detection limit of 21 - 27 mu_mag). There were no flares or planetary transits during the 30.5 days of MOST monitoring with light amplitudes greater than 2 mmag (durations greater than 200 minutes) and 3 mmag (2-200 min durations). While this rules out any close-in planets of >=0.5 Jupiter diameters with an orbital inclination close to 90 deg, the scatter in differential radial velocities permit a close giant planet in a more highly inclined orbit., Comment: 10 figures, accepted by PASP for Dec.2004

We report on the detection of a planetary companion in orbit around the primary star of the binary system $\gamma$ Cephei. High precision radial velocity measurements using 4 independent data sets spanning the time interval 1981--2002 reveal long-lived residual radial velocity variations superimposed on the binary orbit that are coherent in phase and amplitude with a period or 2.48 years (906 days) and a semi-amplitude of 27.5 m s$^{-1}$. We performed a careful analysis of our Ca II H & K S-index measurements, spectral line bisectors, and {\it Hipparcos} photometry. We found no significant variations in these quantities with the 906-d period. We also re-analyzed the Ca II $\lambda$8662 {\AA} measurements of Walker et al. (1992) which showed possible periodic variations with the ``planet'' period when first published. This analysis shows that periodic Ca II equivalent width variations were only present during 1986.5 -- 1992 and absent during 1981--1986.5. Furthermore, a refined period for the Ca II $\lambda$8662 {\AA} variations is 2.14 yrs, significantly less than residual radial velocity period. The most likely explanation of the residual radial velocity variations is a planetary mass companion with $M$ sin $i$ = 1.7 $M_{Jupiter}$ and an orbital semi-major axis of $a_2$ $=$ 2.13 AU. This supports the planet hypothesis for the residual radial velocity variations for $\gamma$ Cep first suggested by Walker et al. (1992). With an estimated binary orbital period of 57 years $\gamma$ Cep is the shortest period binary system in which an extrasolar planet has been found. This system may provide insights into the relationship between planetary and binary star formation., Comment: 19 pages, 15 figures, accepted in Ap. J. Includes additional data and improved orbital solution

We have detected the synchronous enhancement of Ca II H & K emission with the short-period planetary orbit in HD 179949. High-resolution spectra taken on three observing runs extending more than a year show the enhancement coincides with phi ~ 0 (the sub-planetary point) of the 3.093-day orbit with the effect persisting for more than 100 orbits. The synchronous enhancement is consistent with planet-induced chromospheric heating by magnetic rather than tidal interaction. Something which can only be confirmed by further observations. Independent observations are needed to determine whether the stellar rotation is sychronous with the planet's orbit. Of the five 51 Peg-type systems monitored, HD 179949 shows the greatest chromospheric H & K activity. Three others show significant nightly variations but the lack of any phase coherence prevents us saying whether the activity is induced by the planet. Our two standards, tau Ceti and the Sun, show no such nightly variations., Comment: 10 pages, 6 figures. Submitted to ApJ

We have measured the radial velocities of five 51 Peg-type stars and one star with constant velocity. Our measurements, on 20 \AA centered at 3947 \AA, were conventional using Th/Ar comparison spectra taken every 20 or 40 minutes between the stellar exposures. Existing IRAF routines were used for the reduction. We find $\sigma_{RV}$ $\leq$ 20 m s$^{-1}$, provided 4 measurements (out of 72) with residuals $>5\sigma_{RV}$ are neglected. The observations were made with the CFHT Gecko spectrograph, fiber-fed with the CAFE system (R$\sim$110,000). $\sigma_{RV}$ $\leq$10 m s$^{-1}$ seems possible with additional care. This study was incidental to the main program and so not exhaustive but the small value of $\sigma_{RV}$ implies that the fiber feed/image slicer system on Gecko + CAFE, essentially eliminates the long standing problem of guiding errors in radial velocity measurements. We are not suggesting this conventional approach for serious Doppler planet searches (especially with Gecko which has such a small multiplex gain), but the precision is valuable for observations made in spectral regions remote from telluric lines or captive-gas fiducials. Instrument builders might consider the advantages of the CAFE optics which incorporate agitation and invert the object and pupil for slit and grating illumination in future spectrograph designs., Comment: 12 pages, 3 figures

We have detected modulation of the Ca II H&K reversal structure in four out of five 51 Peg-type stars whose planets have orbital periods between 3 and 4 days. We observe two effects in the K-core: (1) a broad 3-A variation at ~1% level and (2) changes on a scale of 0.5 A (~1-3%) in each of the three reversal features. The nightly variations are coherent in both H and K. From differential radial velocities measured to better than 20 m/s, up-to-date phases were extracted. The enhancements in the reversals tend to be greatest at the sub-planetary points which may imply that there is a magnetic interaction between the star's outer layers and the magnetosphere of the planet. These high-S/N (500 per pixel in the continuum) and high-resolution (R = 110,000) data are too few to confirm orbital synchronization., Comment: 4 pages, 2 figures, in newpasp.sty format. To be published by PASP (ed. Drake Deming) in the proceedings of the conference entitled "Scientific Frontiers in Research on Extrasolar Planets," held at the Carnegie Institution of Washington, DC, June 18-21, 2002

We have made a sensitive search for the origin bands in the known electronic transitions of the linear carbon chains C_4 and C_5 at 3789 and 5109 A towards zeta Oph (A_V <= 1). The incentive was a recent detection of C_3 in this interstellar cloud with a column density of 1.6 x 10^12 cm^-2 plus the availability of laboratory gas phase spectra of C_4 and C_5. Further, some models of diffuse interstellar clouds predict that the abundance of these latter species should be within an order of magnitude of C_3. Despite achieving S/N of 2300 to 2600 per pixel at a resolution of ~110,000, the searches were negative, leading to 3 sigma upper limits to the column density of N(C_5) = 2 x 10^11 cm^-2 and N(C_4) = 4 x 10^12-13 cm^-2 where these values rely on theoretically calculated oscillator strengths. The implication of these limits are discussed on the choice of molecules for study in future attempts to identify the carriers of the stronger diffuse interstellar bands., Comment: 12 pages, 3 figures

High precision radial velocity (RV) measurements spanning the years 1980.8--2000.0 are presented for the nearby (3.22 pc) K2 V star $\epsilon$ Eri. These data, which represent a combination of six independent data sets taken with four different telescopes, show convincing variations with a period of $\approx$ 7 yrs. A least squares orbital solution using robust estimation yields orbital parameters of period, $P$ = 6.9 yrs, velocity $K$-amplitude $=$ 19 {\ms}, eccentricity $e$ $=$ 0.6, projected companion mass $M$ sin $i$ = 0.86 $M_{Jupiter}$, and semi-major axis $a_2$ $=$ 3.3 AU. Ca II H&K S-index measurements spanning the same time interval show significant variations with periods of 3 and 20 yrs, yet none at the RV period. If magnetic activity were responsible for the RV variations then it produces a significantly different period than is seen in the Ca II data. Given the lack of Ca II variation with the same period as that found in the RV measurements, the long-lived and coherent nature of these variations, and the high eccentricity of the implied orbit, Keplerian motion due to a planetary companion seems to be the most likely explanation for the observed RV variations. The wide angular separation of the planet from the star (approximately 1 arc-second) and the long orbital period make this planet a prime candidate for both direct imaging and space-based astrometric measurements., Comment: To appear in Astrophysical Journal Letters. 9 pages, 2 figures

We present high spatial resolution, near-IR images in J, H, K of the nucleus of NGC3227, obtained with the Adaptive Optics bonnette on CFHT. The ~0.15 arcsec (17pc) resolution allows structures to be probed in the core region. Dust obscuration becomes significantly less pronounced at longer wavelengths, revealing the true geometry of the core region. We are able to identify two main features in our maps: (i) a spiraling association of knots with a counterpart in an HST F606W image; (ii) a smaller scale annulus, orthogonal to the spiral of knots. These features may provide a means to transport material inwards to fuel the active nucleus., Comment: 10 pages, accepted in MNRAS. A link to higher-res postscript version available at ftp://ftp.ociw.edu/pub/schapman/n3v9.ps.gz

As part of a project to map nearby Seyfert galaxies in the near-IR with adaptive optics, we present high spatial resolution, near-IR images in J,H, and K of the nuclei of NGC 3227 and NGC 2992, obtained with the Adaptive Optics Bonnette (AOB) on CFHT. The ~0.15" resolution allows us to probe structures in the core region at unprecedented scales. With NGC 3227, we are able to identify an inwards spiraling starburst in all three near-IR bands. NGC 2992 shows evidence for emission along a radio loop. Compared with HST optical images, dust obscuration becomes significantly less pronounced at longer wavelengths, revealing the true geometry of the core regions. The observed structures may help to elucidate fueling mechanisms for the central engine, as well as providing insight into the unification paradigms. The results are tempered with the discovery of AOB-related artifacts in the central arcsec of observed AGN galaxies which take on the appearance of spiral/disk structures., Comment: 10 pages, 7 figures, Conference proceeding, "Science with Adaptive Optics", Garching, Germany