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.

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The Exoplanet Handbook

The availability of the Hipparcos Catalogue has triggered many kinematic and dynamical studies of the solar neighbourhood. Nevertheless, those studies generally lacked the third component of the space velocities, i.e., the radial velocities. This work presents the kinematic analysis of 5952 K and 739 M giants in the solar neighbourhood which includes for the first time radial velocity data from a large survey performed with the CORAVEL spectrovelocimeter. It also uses proper motions from the Tycho-2 catalogue, which are expected to be more accurate than the Hipparcos ones. An important by-product of this study is the observed fraction of only 5.7% of spectroscopic binaries among M giants as compared to 13.7% for K giants. After excluding the binaries for which no center-of-mass velocity could be estimated, 5311 K and 719 M giants remain in the final sample.  The UV -plane constructed from these data for the stars with precise parallaxes (%) reveals a rich small-scale structure, with several clumps corresponding to the Hercules stream, the Sirius moving group, and the Hyades and Pleiades superclusters. A maximum-likelihood method, based on a Bayesian approach, has been applied to the data, in order to make full use of all the available stars (not only those with precise parallaxes) and to derive the kinematic properties of these subgroups. Isochrones in the Hertzsprung-Russell diagram reveal a very wide range of ages for stars belonging to these groups. These groups are most probably related to the dynamical perturbation by transient spiral waves (as recently modelled by De Simone et al. [CITE]) rather than to cluster remnants. A possible explanation for the presence of young group/clusters in the same area of the UV -plane is that they have been put there by the spiral wave associated with their formation, while the kinematics of the older stars of our sample has also been disturbed by the same wave. The emerging picture is thus one of dynamical streams pervading the solar neighbourhood and travelling in the Galaxy with similar space velocities. The term dynamical stream is more appropriate than the traditional term supercluster since it involves stars of different ages, not born at the same place nor at the same time. The position of those streams in the UV -plane is responsible for the vertex deviation of  for the whole sample. Our study suggests that the vertex deviation for younger populations could have the same dynamical origin.  The underlying velocity ellipsoid, extracted by the maximum-likelihood method after removal of the streams, is not centered on the value commonly accepted for the radial antisolar motion: it is centered on  km s-1 . However, the full data set (including the various streams) does yield the usual value for the radial solar motion, when properly accounting for the biases inherent to this kind of analysis (namely,  km s-1 ). This discrepancy clearly raises the essential question of how to derive the solar motion in the presence of dynamical perturbations altering the kinematics of the solar neighbourhood: does there exist in the solar neighbourhood a subset of stars having no net radial motion which can be used as a reference against which to measure the solar motion?

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Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data: Revisiting the concept of superclusters

The availability of a number of new interferometric measurements of Main Sequence and subgiant stars makes it possible to calibrate the surface brightness relations of these stars using exclusively direct angular diameter measurements. These empirical laws make it possible to predict the limb darkened angular diameters θ LD of dwarfs and subgiants using their dereddened Johnson magnitudes, or their effective temperature. The smallest intrinsic dispersions of σ ≤ 1% in θ LD are obtained for the relations based on the K and L magnitudes, for instance log θ LD = 0.0502 (B - L) + 0.5133 - 0.2 L or log θ LD = 0.0755 (V - K) + 0.5170 - 0.2 K. Our calibrations are valid between the spectral types A0 and M2 for dwarf stars (with a possible extension to later types when using the effective temperature), and between A0 and K0 for subgiants. Such relations are particularly useful for estimating the angular sizes of calibrators for long-baseline interferometry from readily available broadband photometry.

/pdf/the-angular-sizes-of-dwarf-stars-and-subgiants-surface-16qdz1vpql.pdf

The angular sizes of dwarf stars and subgiants Surface brightness relations calibrated by interferometry

Over the past two years, the search for low-mass extrasolar planets has led to the detection of seven so-called ‘hot Neptunes’ or ‘super-Earths’ around Sun-like stars. These planets have masses 5–20 times larger than the Earth and are mainly found on close-in orbits with periods of 2–15 days. Here we report a system of three Neptune-mass planets with periods of 8.67, 31.6 and 197 days, orbiting the nearby star HD 69830. This star was already known to show an infrared excess possibly caused by an asteroid belt within 1 au (the Sun–Earth distance). Simulations show that the system is in a dynamically stable configuration. Theoretical calculations favour a mainly rocky composition for both inner planets, while the outer planet probably has a significant gaseous envelope surrounding its rocky/icy core; the outer planet orbits within the habitable zone of this star. As the techniques used to search for extrasolar planets have been refined, more and more have been discovered (over 170), and they get smaller. In recent years seven ‘hot Neptunes’ or ‘super-Earths’ have been detected. These have masses 5–20 times larger than the Earth and are in close-in orbits (periods of 2–15 days) around Sun-like stars. Now the first multiple system of three Neptune-mass planets has been found, with periods of 8.67, 31.6 and (in the ‘habitable’ zone) 197 days. They are orbiting the nearby star HD 69830. Theoretical calculations favour a mainly rocky composition for both inner planets. The outer planet probably has a significant gaseous envelope surrounding a rocky/icy core: it is the first Neptune-mass object detected inside the habitable zone of a Sun-like star. Simulations show that the system of three Neptune-mass planets is in a dynamically stable configuration, with theoretical calculations favouring a mainly rocky composition for both inner planets, but a significant gaseous envelope surrounding a rocky/icy core for the outer planet.

An extrasolar planetary system with three Neptune-mass planets

We describe the Navy Prototype Optical Interferometer (NPOI), a joint project of the Naval Research Laboratory (NRL) and the US Naval Observatory (USNO) in cooperation with Lowell Observatory. The NPOI has recently begun operations at the Lowell Observatory site near Flagstaff, Arizona, obtaining its first images, of a binary star, in 1996 May and June and its first limb-darkening observations during 1996 November to 1997 February. This paper gives an overview of the NPOI, including the characteristics of optical interferometry that affect its design. The NPOI includes subarrays for imaging and for astrometry. The imaging subarray consists of six moveable 50 cm siderostats feeding 12 cm apertures, with baseline lengths from 2.0 to 437 m. The astrometric subarray consists of four fixed 50 cm siderostats feeding 12 cm apertures (35 cm apertures to be installed in 1998), with baseline lengths from 19 m to 38 m. The shared back end covers 450-850 nm in 32 channels. The NPOI features vacuum feed and delay systems, active group-delay fringe tracking, and a high degree of automation. The astrometric subarray also includes an extensive site laser metrology system to measure the motions of the siderostats with respect to one another and to the bedrock. For imaging stellar surfaces, arrays with equal spacing between elements are superior to arrays that have been laid out to optimize (u, v) coverage and that therefore have unequal spacing. The imaging subarray of the NPOI provides a number of equally spaced configurations with linear scales at ratios of ≈ 1.64. Unequally spaced configurations are available for a variety of other imaging programs. Coherence across either type of imaging configuration is maintained by "phase bootstrapping": the phases on the longest baselines, on which fringes may be too weak to track, are stabilized by tracking fringes on the shortest baselines. In principle, the four elements of the astrometric subarray provide enough independent baselines to solve for stellar positions and the array geometry simultaneously while observing each of 11 stars only once. The anticipated magnitude limit is 7 mag or better with 12 cm apertures and average seeing; with 35 cm apertures, we expect the limit to be one or more magnitudes fainter. The anticipated wide-angle astrometric precision of the NPOI is ≈ 2 mas. The best angular resolution of the imaging subarray will be ≈ 200 μas. Our experience with the Mark III interferometer suggests that we will be able to measure stellar diameters as small as 200 μas with 1% precision and binary star separations as small as ρ ≈ 65 μas (for Δm ≈ 0 mag) or ρ ≈ 200 μas (for Δm ≈ 3-4 mag). With its large bandwidth and phase bootstrapping, the imaging subarray should be able to make images 10 resolution elements across the disks of nearby late-type stars.

https://iopscience.iop.org/article/10.1086/305365/pdf

The Navy Prototype Optical Interferometer

The principal observational characteristics of the Hipparcos Catalogue, and a summary of its main astrometric and photometric properties, are presented. Median astrometric standard errors (in position, parallax, and annual proper motion) are in the range 0.7-0.9 milliarcsec (mas) for stars brighter than 9 mag at the catalogue epoch (J1991.25). The catalogue is a materialisation of the ICRS reference system, coinciding with its principal axes at the level of ±0.6 mas, and with proper motions consistent with an inertial system at the level of ±0.25 mas/yr. The 118 218 constituent stars provide a mean sky density of ∼ 3 stars deg ―2 . The catalogue is available in printed and machine-readable forms.

https://hal.archives-ouvertes.fr/hal-02053811/document

The Hipparcos catalogue

Launched in August 1989 into a geostationary transfer orbit, the Hipparcos astrometry satellite failed to reach its intended geostationary orbit through the failure of its apogee boost motor. Present indications are that the possible operational lifetime should nevertheless extend beyond the end of 1992, with extremely high-quality scientific data being returned for some 65 per cent of the time. For an assumed 3-year operational lifetime, the original mission goals (positions, parallaxes, and annual proper motions with an accuracy of about 2 milli-arcsec) should be achievable (the pre-launch expectations of the planned 2.5-year mission would be achievable with a 3.5-year mission in the revised orbit)

In-orbit performance of the HIPPARCOS astrometry satellite

Parallaxes and the Hertzsprung-Russell diagram for the preliminary HIPPARCOS solution H30

https://hal.archives-ouvertes.fr/hal-02054107/document

H. Schrijver

Papers

The Hipparcos catalogue

In-orbit performance of the HIPPARCOS astrometry satellite

Parallaxes and the Hertzsprung-Russell diagram for the preliminary HIPPARCOS solution H30

HIPPARCOS distances and mass limits for the planetary candidates: 47 Ursae Majoris, 70 Virginis, and 51 Pegasi

Construction of the intermediate HIPPARCOS astrometric catalogue