We present a catalog of nearby exoplanets. It contains the 172 known lowmass companions with orbi... more We present a catalog of nearby exoplanets. It contains the 172 known lowmass companions with orbits established through radial velocity and transit measurements around stars within 200 pc. We include 5 previously unpublished exoplanets orbiting the stars HD 11964, HD 66428, HD 99109, HD 107148, and HD 164922. We update orbits for 90 additional exoplanets including many whose orbits have not been revised since their announcement, and include radial velocity time series from the Lick, Keck, and Anglo-Australian Observatory planet searches. Both these new and previously published velocities are more precise here due to improvements in our data reduction pipeline, which we applied to archival spectra. We present a brief summary of the global properties of the known exoplanets, including their distributions of orbital semimajor axis, minimum mass, and orbital eccentricity. 1 Note added in proof: Indeed, after submission this paper Lovis et al. (2006) announced a triple-Neptune system orbiting HD 69830, Hatzes et al. (2006) confirmed a 2.3 M Jup planet orbiting Pollux, J. T. Wright et al. (in preparation) announced a planet orbiting HD 154345 and a second planet orbiting HIP 14810, and J. A. Johnson et al. (in preparation) announced a hot Jupiter orbiting HD 185269. Our group will maintain an up-to-date version of the Catalog of Nearby Exoplanets on the World Wide Web at http: //exoplanets.org b When the uncertainty in e is comparable to e, uncertanties in ω and e become non-gaussian. See § 4. c Parameter held fixed in fit. d This parameter is highly uncertain with a non-Gaussian distribution of possible values and high covarience with other parameters. e The period of HD 37124 c is unclear. An alternative interpretation to the data with component 'c' having a period of 29.3 days and slightly different parameters for the other two components is plausible. See Vogt et al. (2005) for details. f The mass of HD 47536 is ill-determined. The solution here is for M = 1.1M ⊙ g Eccentricity held fixed in fit. The quoted error in e represents the change in the e from the best fit required to increase the best-fit χ 2 by 1. h The exoplanets in this system have significant interactions, which renders Keplerian orbital elements inadequate for describing their orbits, since these elements are time-variable. Lee et al. (2005) report the mean anomoly of the inner and outer planets to be 356 • and 227 • , respectively, at a Julian Date of 2451185.1. i This transit emphemeris is expressed as a Heliocentric Judian Day j Charbonneau et al. (2005) find e cos ω = 0.003 ± 0.0019 k The exoplanets in this system have significant interactions, which renders Keplerian orbital elements inadequate for describing their orbits, since these elements are time-variable. Correia et al. (2005) report the
Precise Doppler measurements from the Anglo-Australian Telescope (AAT) UCLES spectrometer reveal ... more Precise Doppler measurements from the Anglo-Australian Telescope (AAT) UCLES spectrometer reveal periodic Keplerian velocity variations in the stars HD 160691 and HD 27442. HD 160691 has a period of 743 days, a semiamplitude of 54 m s~1, and a high eccentricity, e \ 0.62, typical of extrasolar planets orbiting beyond 0.2 AU. The minimum (M sin i) mass of the companion is 1.97 and the M J , semimajor axis is 1.65 AU. HD 27442 has a 415 day period, a semiamplitude of 32 m s~1, and an eccentricity of 0.058. The minimum mass is 1.43 and the semimajor axis is 1.18 AU. This is the Ðrst M J , extrasolar planet orbiting beyond 0.2 AU that is in a circular orbit similar to solar system planets. The photon-limited precision of AAT/UCLES measurements is 3 m s~1 as demonstrated by stable stars and Keplerian Ðts to planet-bearing stars. In addition, we present conÐrmation of four previously announced planets.
We report results from the Anglo-Australian Planet Search -a survey for planets around 200 solar-... more We report results from the Anglo-Australian Planet Search -a survey for planets around 200 solar-type stars in the southern hemisphere, which is being carried out on the 3.9m Anglo-Australian Telescope. Limiting Doppler precisions of 3 m s −1 have been demonstrated from the first 2.5 years of operation, making this the highest precision planet search in the southern hemisphere. From these data we report results for two new sub-stellar detections. The first is a "51 Peg"-like planet around the star HD 179949 with M sin i = 0.84 M JUP . Photometric study reveals this is not a transiting system. The second is a brown dwarf or very low-mass star companion to HD 164427 in an eccentric orbit with M sin i = 46 M JUP . Hipparcos data indicate this latter object is unlikely to have a mass greater than 0.18M ⊙ .
Giant planets orbiting stars other than the Sun are clearly detectable through precise radial-vel... more Giant planets orbiting stars other than the Sun are clearly detectable through precise radial-velocity measurements of the orbital reflex motion of the parent star. In the four years since the discovery 1 of the companion to the star 51 Peg, similar low-amplitude "Doppler star wobbles" have revealed the presence of some 20 planets orbiting nearby solartype stars. Several of these newly-discovered planets 2, 3, 4 are very close to their parent stars, in orbits with periods of only a few days. Being an indirect technique, however, the reflex-velocity method has little to say about the sizes or compositions of the planets, and can only place lower limits on their masses. Here we report the use of high-resolution optical spectroscopy to achieve a probable detection of the Doppler-shifted signature of starlight reflected from one of these objects, the giant exoplanet orbiting the star τ Boötis. Our data give the planet's orbital inclination i = 29 • , indicating that its mass is some 8 times that of Jupiter, and suggest strongly that the planet has the size and reflectivity expected for a gas-giant planet.
The Geneva group has reported two Saturn-mass planets orbiting HD 83443 (K0V) with periods of 2.9... more The Geneva group has reported two Saturn-mass planets orbiting HD 83443 (K0V) with periods of 2.98 and 29.8 d. The two planets have raised interest in their dynamics because of the possible 10:1 orbital resonance and the strong gravitational interactions. We report precise Doppler measurements of HD 83443 obtained with the Keck/HIRES and the AAT/UCLES spectrometers. These measurements strongly confirm the inner planet with period of 2.985 d, with orbital parameters in very good agreement with those of the Geneva group. However these Doppler measurements show no evidence of the outer planet, at thresholds of 1/4 (3 m s −1 ) of the reported velocity amplitude of 13.8 m s −1 . Thus, -2the existence of the outer planet is in question. Indeed, the current Doppler measurements reveal no evidence of any second planet with periods less than a year.
New radial velocities of α Cen A & B obtained in the framework the Anglo-Australian Planet Search... more New radial velocities of α Cen A & B obtained in the framework the Anglo-Australian Planet Search programme as well as in the CORALIE programme are added to those by to improve the precision of the orbital parameters. The resulting masses are 1.105 ± 0.0070 M and 0.934 ± 0.0061 M for A and B respectively. The factors limiting how accurately these masses can be derived from a combined visual-spectroscopic solution are investigated. The total effect of the convective blueshift and the gravitational redshift is also investigated and estimated to differ by 215 ± 8 m s −1 between the components. This suggests that the difference in convective blueshift between the components is much smaller than predicted from current hydrodynamical model atmosphere calculations.
In data from three clear nights of a WHT/UES run in 2000 Oct/Nov, and using improved Doppler tomo... more In data from three clear nights of a WHT/UES run in 2000 Oct/Nov, and using improved Doppler tomographic signal-analysis techniques, we have carried out a deep search for starlight reflected from the innermost of υ (upsilon) And's three planets. We place upper limits on the planet's radius R p as functions of its projected orbital velocity K p ≈ 139 sin i km s −1 for various assumptions about the wavelengthdependent geometric albedo spectrum p(λ) of its atmosphere. For a grey albedo p we find R p √ p < 0.98 R J with 0.1% false-alarm probability (4-σ). For a Sudarsky, Burrows & Pinto (1999) Class V model atmosphere, the mean albedo in our 380-676 nm bandpass is p ∼ 0.42, requiring R p < 1.51 R J , while an (isolated) Class IV model with p ∼ 0.19 requires R p < 2.23 R J . The star's v rot sin i ∼ 10 km s −1 and estimated rotation period P rot ∼ 10d suggest a high orbital inclination i ∼ 70 − 80 • . We also develop methods for assessing the false-alarm probabilities of faint candidate detections, and for extracting information about the albedo spectrum and other planetary parameters from faint reflected-light signals.
Using improved doppler tomographic signal-analysis techniques we have carried out a deep search f... more Using improved doppler tomographic signal-analysis techniques we have carried out a deep search for starlight reflected from the giant planet orbiting the star τ Bootis. We combined echelle spectra secured at the 4.2 m William Herschel telescope in 1998 and 1999 (which yielded a tentative detection of a reflected starlight component from the orbiting companion) with new data obtained in 2000 (which failed to confirm the detection). The combined dataset comprises 893 high resolution spectra with a total integration time of 75 hr 32 min spanning 17 nights. We establish an upper limit on the planet's geometric albedo p < 0.39 (at the 99.9% significance level) at the most probable orbital inclination i ≃ 36 • , assuming a grey albedo, a Venus-like phase function and a planetary radius R p = 1.2R Jup . We are able to rule out some combinations of the predicted planetary radius and atmospheric albedo models with high, reflective cloud decks. Although a weak candidate signal appears near to the most probable radial velocity amplitude, its statistical significance is insufficient for us to claim a detection with any confidence.
We report the detection of two new extra-solar planets from the Anglo-Australian Planet Search ar... more We report the detection of two new extra-solar planets from the Anglo-Australian Planet Search around the stars HD 142 and HD 23079. The planet orbiting HD 142 has an orbital period of just under one year, while that orbiting HD 23079 has a period of just under two years. HD 142 falls into the class of "eccentric" gas giants. HD 23079 lies in the recently uncovered class of "ǫ Ret-like" planets -extra-solar gas giant planets with near-circular orbits outside 0.1 a.u. The recent discovery of several more members of this class provides new impetus for the extension of existing planet searches to longer periods, in the search for Jupiter-like planets in Jupiter-like orbits.
We report Doppler measurements of the stars HD 187085 and HD 20782 which indicate two high eccent... more We report Doppler measurements of the stars HD 187085 and HD 20782 which indicate two high eccentricity low-mass companions to the stars. We find HD 187085 has a Jupiter-mass companion with a ∼1000 d orbit. Our formal 'best fit' solution suggests an eccentricity of 0.47, however, it does not sample the periastron passage of the companion and we find that orbital solutions with eccentricities between 0.1 and 0.8 give only slightly poorer fits (based on RMS and χ 2 ν ) and are thus plausible. Observations made during periastron passage in 2007 June should allow for the reliable determination of the orbital eccentricity for the companion to HD 187085. Our dataset for HD 20782 does sample periastron and so the orbit for its companion can be more reliably determined. We find the companion to HD 20782 has M sin i = 1.77±0.22 M Jup , an orbital period of 595.86±0.03 d and an orbit with an eccentricity of 0.92±0.03. The detection of such high-eccentricity (and relatively low velocity amplitude) exoplanets appears to be facilitated by the long-term precision of the Anglo-Australian Planet Search. Looking at exoplanet detections as a whole, we find that those with higher eccentricity seem to have relatively higher velocity amplitudes indicating higher mass planets and/or an observational bias against the detection of high eccentricity systems.
Precise Doppler measurements from the AAT/UCLES spectrometer reveal two companions to both HD 154... more Precise Doppler measurements from the AAT/UCLES spectrometer reveal two companions to both HD 154857 and HD 160691. The inner companion to HD 154857 has a period of 398 d, an eccentricity of 0.51, and a minimum mass of 1.8 M JUP . An outer companion has a period much longer than 2 years and is currently detected only as a linear trend of 14 m s −1 per year. The inner companion to HD 160691, previously announced from AAT data, has a period of 645 d, an eccentricity of 0.20, and a minimum mass of 1.7 M JUP . For the outer planet, whose orbit is less well constrained, a two Keplerian fit yields a period of 8.2 yr, an eccentricity of 0.57, and a minimum mass of 3.1 M JUP . With these orbital parameters, its maximum separation from the star of 0.4 arcsec makes it a viable target for direct imaging.
We present the results of ultraviolet echelle spectroscopy of a sample of fifty nine F,G,K and M ... more We present the results of ultraviolet echelle spectroscopy of a sample of fifty nine F,G,K and M stars from the Anglo-Australian Planet Search target list. Ca II activity indices, which are essential in the interpretation of planet detection claims, have been determined for these stars and placed on the Mount Wilson R ′ HK system.
We report the detection of a extrasolar planet candidate orbiting the G1 V star HD 39091. The orb... more We report the detection of a extrasolar planet candidate orbiting the G1 V star HD 39091. The orbital period is 2083 d and the eccentricity is 0.62.
We report the detection of four new extrasolar planets from the Anglo-Australian Planet Search or... more We report the detection of four new extrasolar planets from the Anglo-Australian Planet Search orbiting the metal-enriched stars HD 73526, HD 76700, HD 30177, and HD 2039. The planetary companion of HD 76700 has a circular orbit with a period of 3.98 days. With M sin i ¼ 0:197 AE 0:017 ð Þ M J , or 0.69M SAT , it is one of the lowest minimum mass extrasolar planets yet detected. The remaining planets all have elliptical orbits with periods ranging from 190.5 days to 4.4 yr. All four planets have been found orbiting hosts from a subsample of 20 metal-enriched and faint (V < 9) stars, which was added to the Anglo-Australian Planet Search's magnitude-limited V < 7:5 main sample in 1999 October. These stars were selected for metal enrichment on the basis of their Strö mgren photometry, and their enrichment has been subsequently confirmed by detailed spectroscopic analysis.
We have acquired high-resolution echelle spectra of 225 F6-M5 type stars in the southern hemisphe... more We have acquired high-resolution echelle spectra of 225 F6-M5 type stars in the southern hemisphere. The stars are targets or candidates to be targets for the Anglo-Australian Planet Search. CaII HK line cores were used to derive activity indices for all of these objects. The indices were converted to the Mt. Wilson system of measurements and logR ′ HK values determined. A number of these stars had no previously derived activity indices. In addition we have also included the stars from Tinney et al. using our Mt. Wilson calibration. The radial-velocity instability (also known as jitter ) level was determined for all 21 planet-host stars in our dataset. We find the jitter to be at a level considerably below the radial-velocity signatures in all but one of these systems. 19 stars from our sample were found to be active (logR ′ HK > -4.5) and thus have high levels of jitter. Radial-velocity analysis for planetary companions to these stars should precede with caution.
Precision Doppler velocity measurements from the 3.9-m Anglo-Australian Telescope reveal a planet... more Precision Doppler velocity measurements from the 3.9-m Anglo-Australian Telescope reveal a planet with a 6 year period orbiting the G5 dwarf HD 70642. The a = 3.3 AU orbit has a low eccentricity (e = 0.1), and the minimum (M sin i ) mass of the planet is 2.0 M JUP . The host star is metal rich relative to the Sun, similar to most stars with known planets. The distant and approximately circular orbit of this planet makes it a member of a rare group to emerge from precision Doppler surveys.
We have used a doppler tomographic analysis to conduct a deep search for the starlight reflected ... more We have used a doppler tomographic analysis to conduct a deep search for the starlight reflected from the planetary companion to HD 75289. In 4 nights on VLT2/UVES in January 2003, we obtained 684 high resolutionéchelle spectra with a total integration time of 26 hours. We establish an upper limit on the planet's geometric albedo p < 0.12 (to the 99.9% significance level) at the most probable orbital inclination i ≃ 60 • , assuming a grey albedo, a Venus-like phase function and a planetary radius R p = 1.6R Jup . We are able to rule out some combinations of the predicted planetary radius and atmospheric albedo models with high, reflective cloud decks.
We present a catalog of nearby exoplanets. It contains the 172 known lowmass companions with orbi... more We present a catalog of nearby exoplanets. It contains the 172 known lowmass companions with orbits established through radial velocity and transit measurements around stars within 200 pc. We include 5 previously unpublished exoplanets orbiting the stars HD 11964, HD 66428, HD 99109, HD 107148, and HD 164922. We update orbits for 90 additional exoplanets including many whose orbits have not been revised since their announcement, and include radial velocity time series from the Lick, Keck, and Anglo-Australian Observatory planet searches. Both these new and previously published velocities are more precise here due to improvements in our data reduction pipeline, which we applied to archival spectra. We present a brief summary of the global properties of the known exoplanets, including their distributions of orbital semimajor axis, minimum mass, and orbital eccentricity. 1 Note added in proof: Indeed, after submission this paper Lovis et al. (2006) announced a triple-Neptune system orbiting HD 69830, Hatzes et al. (2006) confirmed a 2.3 M Jup planet orbiting Pollux, J. T. Wright et al. (in preparation) announced a planet orbiting HD 154345 and a second planet orbiting HIP 14810, and J. A. Johnson et al. (in preparation) announced a hot Jupiter orbiting HD 185269. Our group will maintain an up-to-date version of the Catalog of Nearby Exoplanets on the World Wide Web at http: //exoplanets.org b When the uncertainty in e is comparable to e, uncertanties in ω and e become non-gaussian. See § 4. c Parameter held fixed in fit. d This parameter is highly uncertain with a non-Gaussian distribution of possible values and high covarience with other parameters. e The period of HD 37124 c is unclear. An alternative interpretation to the data with component 'c' having a period of 29.3 days and slightly different parameters for the other two components is plausible. See Vogt et al. (2005) for details. f The mass of HD 47536 is ill-determined. The solution here is for M = 1.1M ⊙ g Eccentricity held fixed in fit. The quoted error in e represents the change in the e from the best fit required to increase the best-fit χ 2 by 1. h The exoplanets in this system have significant interactions, which renders Keplerian orbital elements inadequate for describing their orbits, since these elements are time-variable. Lee et al. (2005) report the mean anomoly of the inner and outer planets to be 356 • and 227 • , respectively, at a Julian Date of 2451185.1. i This transit emphemeris is expressed as a Heliocentric Judian Day j Charbonneau et al. (2005) find e cos ω = 0.003 ± 0.0019 k The exoplanets in this system have significant interactions, which renders Keplerian orbital elements inadequate for describing their orbits, since these elements are time-variable. Correia et al. (2005) report the
Precise Doppler measurements from the Anglo-Australian Telescope (AAT) UCLES spectrometer reveal ... more Precise Doppler measurements from the Anglo-Australian Telescope (AAT) UCLES spectrometer reveal periodic Keplerian velocity variations in the stars HD 160691 and HD 27442. HD 160691 has a period of 743 days, a semiamplitude of 54 m s~1, and a high eccentricity, e \ 0.62, typical of extrasolar planets orbiting beyond 0.2 AU. The minimum (M sin i) mass of the companion is 1.97 and the M J , semimajor axis is 1.65 AU. HD 27442 has a 415 day period, a semiamplitude of 32 m s~1, and an eccentricity of 0.058. The minimum mass is 1.43 and the semimajor axis is 1.18 AU. This is the Ðrst M J , extrasolar planet orbiting beyond 0.2 AU that is in a circular orbit similar to solar system planets. The photon-limited precision of AAT/UCLES measurements is 3 m s~1 as demonstrated by stable stars and Keplerian Ðts to planet-bearing stars. In addition, we present conÐrmation of four previously announced planets.
We report results from the Anglo-Australian Planet Search -a survey for planets around 200 solar-... more We report results from the Anglo-Australian Planet Search -a survey for planets around 200 solar-type stars in the southern hemisphere, which is being carried out on the 3.9m Anglo-Australian Telescope. Limiting Doppler precisions of 3 m s −1 have been demonstrated from the first 2.5 years of operation, making this the highest precision planet search in the southern hemisphere. From these data we report results for two new sub-stellar detections. The first is a "51 Peg"-like planet around the star HD 179949 with M sin i = 0.84 M JUP . Photometric study reveals this is not a transiting system. The second is a brown dwarf or very low-mass star companion to HD 164427 in an eccentric orbit with M sin i = 46 M JUP . Hipparcos data indicate this latter object is unlikely to have a mass greater than 0.18M ⊙ .
Giant planets orbiting stars other than the Sun are clearly detectable through precise radial-vel... more Giant planets orbiting stars other than the Sun are clearly detectable through precise radial-velocity measurements of the orbital reflex motion of the parent star. In the four years since the discovery 1 of the companion to the star 51 Peg, similar low-amplitude "Doppler star wobbles" have revealed the presence of some 20 planets orbiting nearby solartype stars. Several of these newly-discovered planets 2, 3, 4 are very close to their parent stars, in orbits with periods of only a few days. Being an indirect technique, however, the reflex-velocity method has little to say about the sizes or compositions of the planets, and can only place lower limits on their masses. Here we report the use of high-resolution optical spectroscopy to achieve a probable detection of the Doppler-shifted signature of starlight reflected from one of these objects, the giant exoplanet orbiting the star τ Boötis. Our data give the planet's orbital inclination i = 29 • , indicating that its mass is some 8 times that of Jupiter, and suggest strongly that the planet has the size and reflectivity expected for a gas-giant planet.
The Geneva group has reported two Saturn-mass planets orbiting HD 83443 (K0V) with periods of 2.9... more The Geneva group has reported two Saturn-mass planets orbiting HD 83443 (K0V) with periods of 2.98 and 29.8 d. The two planets have raised interest in their dynamics because of the possible 10:1 orbital resonance and the strong gravitational interactions. We report precise Doppler measurements of HD 83443 obtained with the Keck/HIRES and the AAT/UCLES spectrometers. These measurements strongly confirm the inner planet with period of 2.985 d, with orbital parameters in very good agreement with those of the Geneva group. However these Doppler measurements show no evidence of the outer planet, at thresholds of 1/4 (3 m s −1 ) of the reported velocity amplitude of 13.8 m s −1 . Thus, -2the existence of the outer planet is in question. Indeed, the current Doppler measurements reveal no evidence of any second planet with periods less than a year.
New radial velocities of α Cen A & B obtained in the framework the Anglo-Australian Planet Search... more New radial velocities of α Cen A & B obtained in the framework the Anglo-Australian Planet Search programme as well as in the CORALIE programme are added to those by to improve the precision of the orbital parameters. The resulting masses are 1.105 ± 0.0070 M and 0.934 ± 0.0061 M for A and B respectively. The factors limiting how accurately these masses can be derived from a combined visual-spectroscopic solution are investigated. The total effect of the convective blueshift and the gravitational redshift is also investigated and estimated to differ by 215 ± 8 m s −1 between the components. This suggests that the difference in convective blueshift between the components is much smaller than predicted from current hydrodynamical model atmosphere calculations.
In data from three clear nights of a WHT/UES run in 2000 Oct/Nov, and using improved Doppler tomo... more In data from three clear nights of a WHT/UES run in 2000 Oct/Nov, and using improved Doppler tomographic signal-analysis techniques, we have carried out a deep search for starlight reflected from the innermost of υ (upsilon) And's three planets. We place upper limits on the planet's radius R p as functions of its projected orbital velocity K p ≈ 139 sin i km s −1 for various assumptions about the wavelengthdependent geometric albedo spectrum p(λ) of its atmosphere. For a grey albedo p we find R p √ p < 0.98 R J with 0.1% false-alarm probability (4-σ). For a Sudarsky, Burrows & Pinto (1999) Class V model atmosphere, the mean albedo in our 380-676 nm bandpass is p ∼ 0.42, requiring R p < 1.51 R J , while an (isolated) Class IV model with p ∼ 0.19 requires R p < 2.23 R J . The star's v rot sin i ∼ 10 km s −1 and estimated rotation period P rot ∼ 10d suggest a high orbital inclination i ∼ 70 − 80 • . We also develop methods for assessing the false-alarm probabilities of faint candidate detections, and for extracting information about the albedo spectrum and other planetary parameters from faint reflected-light signals.
Using improved doppler tomographic signal-analysis techniques we have carried out a deep search f... more Using improved doppler tomographic signal-analysis techniques we have carried out a deep search for starlight reflected from the giant planet orbiting the star τ Bootis. We combined echelle spectra secured at the 4.2 m William Herschel telescope in 1998 and 1999 (which yielded a tentative detection of a reflected starlight component from the orbiting companion) with new data obtained in 2000 (which failed to confirm the detection). The combined dataset comprises 893 high resolution spectra with a total integration time of 75 hr 32 min spanning 17 nights. We establish an upper limit on the planet's geometric albedo p < 0.39 (at the 99.9% significance level) at the most probable orbital inclination i ≃ 36 • , assuming a grey albedo, a Venus-like phase function and a planetary radius R p = 1.2R Jup . We are able to rule out some combinations of the predicted planetary radius and atmospheric albedo models with high, reflective cloud decks. Although a weak candidate signal appears near to the most probable radial velocity amplitude, its statistical significance is insufficient for us to claim a detection with any confidence.
We report the detection of two new extra-solar planets from the Anglo-Australian Planet Search ar... more We report the detection of two new extra-solar planets from the Anglo-Australian Planet Search around the stars HD 142 and HD 23079. The planet orbiting HD 142 has an orbital period of just under one year, while that orbiting HD 23079 has a period of just under two years. HD 142 falls into the class of "eccentric" gas giants. HD 23079 lies in the recently uncovered class of "ǫ Ret-like" planets -extra-solar gas giant planets with near-circular orbits outside 0.1 a.u. The recent discovery of several more members of this class provides new impetus for the extension of existing planet searches to longer periods, in the search for Jupiter-like planets in Jupiter-like orbits.
We report Doppler measurements of the stars HD 187085 and HD 20782 which indicate two high eccent... more We report Doppler measurements of the stars HD 187085 and HD 20782 which indicate two high eccentricity low-mass companions to the stars. We find HD 187085 has a Jupiter-mass companion with a ∼1000 d orbit. Our formal 'best fit' solution suggests an eccentricity of 0.47, however, it does not sample the periastron passage of the companion and we find that orbital solutions with eccentricities between 0.1 and 0.8 give only slightly poorer fits (based on RMS and χ 2 ν ) and are thus plausible. Observations made during periastron passage in 2007 June should allow for the reliable determination of the orbital eccentricity for the companion to HD 187085. Our dataset for HD 20782 does sample periastron and so the orbit for its companion can be more reliably determined. We find the companion to HD 20782 has M sin i = 1.77±0.22 M Jup , an orbital period of 595.86±0.03 d and an orbit with an eccentricity of 0.92±0.03. The detection of such high-eccentricity (and relatively low velocity amplitude) exoplanets appears to be facilitated by the long-term precision of the Anglo-Australian Planet Search. Looking at exoplanet detections as a whole, we find that those with higher eccentricity seem to have relatively higher velocity amplitudes indicating higher mass planets and/or an observational bias against the detection of high eccentricity systems.
Precise Doppler measurements from the AAT/UCLES spectrometer reveal two companions to both HD 154... more Precise Doppler measurements from the AAT/UCLES spectrometer reveal two companions to both HD 154857 and HD 160691. The inner companion to HD 154857 has a period of 398 d, an eccentricity of 0.51, and a minimum mass of 1.8 M JUP . An outer companion has a period much longer than 2 years and is currently detected only as a linear trend of 14 m s −1 per year. The inner companion to HD 160691, previously announced from AAT data, has a period of 645 d, an eccentricity of 0.20, and a minimum mass of 1.7 M JUP . For the outer planet, whose orbit is less well constrained, a two Keplerian fit yields a period of 8.2 yr, an eccentricity of 0.57, and a minimum mass of 3.1 M JUP . With these orbital parameters, its maximum separation from the star of 0.4 arcsec makes it a viable target for direct imaging.
We present the results of ultraviolet echelle spectroscopy of a sample of fifty nine F,G,K and M ... more We present the results of ultraviolet echelle spectroscopy of a sample of fifty nine F,G,K and M stars from the Anglo-Australian Planet Search target list. Ca II activity indices, which are essential in the interpretation of planet detection claims, have been determined for these stars and placed on the Mount Wilson R ′ HK system.
We report the detection of a extrasolar planet candidate orbiting the G1 V star HD 39091. The orb... more We report the detection of a extrasolar planet candidate orbiting the G1 V star HD 39091. The orbital period is 2083 d and the eccentricity is 0.62.
We report the detection of four new extrasolar planets from the Anglo-Australian Planet Search or... more We report the detection of four new extrasolar planets from the Anglo-Australian Planet Search orbiting the metal-enriched stars HD 73526, HD 76700, HD 30177, and HD 2039. The planetary companion of HD 76700 has a circular orbit with a period of 3.98 days. With M sin i ¼ 0:197 AE 0:017 ð Þ M J , or 0.69M SAT , it is one of the lowest minimum mass extrasolar planets yet detected. The remaining planets all have elliptical orbits with periods ranging from 190.5 days to 4.4 yr. All four planets have been found orbiting hosts from a subsample of 20 metal-enriched and faint (V < 9) stars, which was added to the Anglo-Australian Planet Search's magnitude-limited V < 7:5 main sample in 1999 October. These stars were selected for metal enrichment on the basis of their Strö mgren photometry, and their enrichment has been subsequently confirmed by detailed spectroscopic analysis.
We have acquired high-resolution echelle spectra of 225 F6-M5 type stars in the southern hemisphe... more We have acquired high-resolution echelle spectra of 225 F6-M5 type stars in the southern hemisphere. The stars are targets or candidates to be targets for the Anglo-Australian Planet Search. CaII HK line cores were used to derive activity indices for all of these objects. The indices were converted to the Mt. Wilson system of measurements and logR ′ HK values determined. A number of these stars had no previously derived activity indices. In addition we have also included the stars from Tinney et al. using our Mt. Wilson calibration. The radial-velocity instability (also known as jitter ) level was determined for all 21 planet-host stars in our dataset. We find the jitter to be at a level considerably below the radial-velocity signatures in all but one of these systems. 19 stars from our sample were found to be active (logR ′ HK > -4.5) and thus have high levels of jitter. Radial-velocity analysis for planetary companions to these stars should precede with caution.
Precision Doppler velocity measurements from the 3.9-m Anglo-Australian Telescope reveal a planet... more Precision Doppler velocity measurements from the 3.9-m Anglo-Australian Telescope reveal a planet with a 6 year period orbiting the G5 dwarf HD 70642. The a = 3.3 AU orbit has a low eccentricity (e = 0.1), and the minimum (M sin i ) mass of the planet is 2.0 M JUP . The host star is metal rich relative to the Sun, similar to most stars with known planets. The distant and approximately circular orbit of this planet makes it a member of a rare group to emerge from precision Doppler surveys.
We have used a doppler tomographic analysis to conduct a deep search for the starlight reflected ... more We have used a doppler tomographic analysis to conduct a deep search for the starlight reflected from the planetary companion to HD 75289. In 4 nights on VLT2/UVES in January 2003, we obtained 684 high resolutionéchelle spectra with a total integration time of 26 hours. We establish an upper limit on the planet's geometric albedo p < 0.12 (to the 99.9% significance level) at the most probable orbital inclination i ≃ 60 • , assuming a grey albedo, a Venus-like phase function and a planetary radius R p = 1.6R Jup . We are able to rule out some combinations of the predicted planetary radius and atmospheric albedo models with high, reflective cloud decks.
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Papers by Alan Penny