1. Introduction 2. Radial velocities 3. Astrometry 4. Timing 5. Microlensing 6. Transits 7. Imaging 8. Host stars 9. Brown dwarfs and free-floating planets 10. Formation and evolution 11. Interiors and atmospheres 12. The Solar System Appendixes References Index.

/pdf/the-exoplanet-handbook-3g3nzlvc20.pdf

The Exoplanet Handbook

The Second Workshop on Extreme Precision Radial Velocities defined circa 2015 the state of the art Doppler precision and identified the critical path challenges for reaching 10 cm/s measurement precision. The presentations and discussion of key issues for instrumentation and data analysis and the workshop recommendations for achieving this precision are summarized here. 
Beginning with the HARPS spectrograph, technological advances for precision radial velocity measurements have focused on building extremely stable instruments. To reach still higher precision, future spectrometers will need to produce even higher fidelity spectra. This should be possible with improved environmental control, greater stability in the illumination of the spectrometer optics, better detectors, more precise wavelength calibration, and broader bandwidth spectra. Key data analysis challenges for the precision radial velocity community include distinguishing center of mass Keplerian motion from photospheric velocities, and the proper treatment of telluric contamination. Success here is coupled to the instrument design, but also requires the implementation of robust statistical and modeling techniques. Center of mass velocities produce Doppler shifts that affect every line identically, while photospheric velocities produce line profile asymmetries with wavelength and temporal dependencies that are different from Keplerian signals. 
Exoplanets are an important subfield of astronomy and there has been an impressive rate of discovery over the past two decades. Higher precision radial velocity measurements are required to serve as a discovery technique for potentially habitable worlds and to characterize detections from transit missions. The future of exoplanet science has very different trajectories depending on the precision that can ultimately be achieved with Doppler measurements.

/pdf/state-of-the-field-extreme-precision-radial-velocities-2q3ixdycpa.pdf

State of the Field: Extreme Precision Radial Velocities

The Second Workshop on Extreme Precision Radial Velocities defined circa 2015 the state of the art Doppler precision and identified the critical path challenges for reaching 10 cm s^(−1) measurement precision. The presentations and discussion of key issues for instrumentation and data analysis and the workshop recommendations for achieving this bold precision are summarized here. Beginning with the High Accuracy Radial Velocity Planet Searcher spectrograph, technological advances for precision radial velocity (RV) measurements have focused on building extremely stable instruments. To reach still higher precision, future spectrometers will need to improve upon the state of the art, producing even higher fidelity spectra. This should be possible with improved environmental control, greater stability in the illumination of the spectrometer optics, better detectors, more precise wavelength calibration, and broader bandwidth spectra. Key data analysis challenges for the precision RV community include distinguishing center of mass (COM) Keplerian motion from photospheric velocities (time correlated noise) and the proper treatment of telluric contamination. Success here is coupled to the instrument design, but also requires the implementation of robust statistical and modeling techniques. COM velocities produce Doppler shifts that affect every line identically, while photospheric velocities produce line profile asymmetries with wavelength and temporal dependencies that are different from Keplerian signals. Exoplanets are an important subfield of astronomy and there has been an impressive rate of discovery over the past two decades. However, higher precision RV measurements are required to serve as a discovery technique for potentially habitable worlds, to confirm and characterize detections from transit missions, and to provide mass measurements for other space-based missions. The future of exoplanet science has very different trajectories depending on the precision that can ultimately be achieved with Doppler measurements.

/pdf/state-of-the-field-extreme-precision-radial-velocities-418gigyr14.pdf

State of the Field: Extreme Precision Radial Velocities*

We report on the discovery of a substellar companion or a massive Jupiter orbiting the G5V star HD 16760 using the spectrograph SOPHIE installed on the OHP 1.93-m telescope. Characteristics and performances of the spectrograph are presented, as well as the SOPHIE exoplanet consortium program. With a minimum mass of 14.3 MJup, an orbital period of 465 days and an eccentricity of 0.067, HD 16760b seems to be located just at the end of the mass distribution of giant planets, close to the planet/brown-dwarf transition. Its quite circular orbit supports a formation in a gaseous protoplanetary disk.

/pdf/the-sophie-search-for-northern-extrasolar-planets-i-a-42s27onpsq.pdf

The SOPHIE search for northern extrasolar planets . I. A companion around HD 16760 with mass close to the planet/brown-dwarf transition

For Gaia DR2 (GDR2), 280 million spectra, collected by the RVS instrument on-board Gaia, were processed and median radial velocities were derived for 9.8 million sources brighter than Grvs = 12 mag. This paper describes the validation and properties of the median radial velocities published in GDR2. Quality tests and filters are applied to select, from the 9.8 million radial velocities, those with the quality to be published in GDR2. The accuracy of the selected sample is assessed with respect to ground-based catalogues. Its precision is estimated using both ground-based catalogues and the distribution of the Gaia radial velocity uncertainties. GDR2 contains median radial velocities for 7 224 631 stars, with Teff in the range [3550, 6900] K, which passed succesfully the quality tests. The published median radial velocities provide a full sky-coverage and have a completness with respect to the astrometric data of 77.2\% (for $G \leq 12.5$ mag). The median radial velocity residuals with respect to the ground-based surveys vary from one catalogue to another, but do not exceed a few 100s m/s. In addition, the Gaia radial velocities show a positive trend as a function of magnitude, which starts around Grvs $\sim 9$ mag and reaches about $+500$ m/s at Grvs $= 11.75$ mag. The overall precision, estimated from the median of the Gaia radial velocity uncertainties, is 1.05 km/s. The radial velocity precision is function of many parameters, in particular the magnitude and effective temperature. For bright stars, Grvs in [4, 8] mag, the precision is in the range 200-350 m/s, which is about 3 to 5 times more precise than the pre-launch specification of 1 km/s. At the faint end, Grvs = 11.75 mag, the precisions for Teff = 5000 K and 6500 K are respectively 1.4 km/s and 3.7 km/s.

/pdf/gaia-data-release-2-properties-and-validation-of-the-radial-3bl7tx4o5s.pdf

Gaia Data Release 2: Properties and validation of the radial velocities

SOPHIE is a new fiber-fed echelle spectrograph in operation since October 2006 at the 1.93-m telescope of Observatoire de Haute-Provence. Benefiting from experience acquired on HARPS (3.6-m ESO), SOPHIE was designed to obtain accurate radial velocities (~3 m/s over several months) with much higher optical throughput than ELODIE (by a factor of 10). These enhanced capabilities have actually been achieved and have proved invaluable in asteroseismology and exoplanetology. We present here the optical concept, a double-pass Schmidt echelle spectrograph associated with a high efficiency coupling fiber system, and including simultaneous wavelength calibration. Stability of the projected spectrum has been obtained by the encapsulation of the dispersive components in a constant pressure tank. The main characteristics of the instrument are described. We also give some technical details used in reaching this high level of performance.

/pdf/the-sophie-spectrograph-design-and-technical-key-points-for-120ex5a5dz.pdf

C. Carol

Papers

The SOPHIE spectrograph: design and technical key-points for high throughput and high stability