A consideration of the use of optical fibers to remotely couple photometers to telescopes

The possible use of optical fibers to remotely couple photometers to telescopes is considered. Such an application offers the apparent prospect of enhancing photometric stability as a consequence of the benefits of remote operation and decreased sensitivity to image details. A properly designed fiber optic coupler will probably show no significant changes in optical transmisssion due to normal variations in the fiber configuration. It may be more difficult to eliminate configuration-dependent effects on the pupil of the transmitted beam, and thus achieve photometric stability to guiding and seeing errors. In addition, there is some evidence for significant changes in the optical throughputs of fibers over the temperature range normally encountered in astronomical observatories

Spectral Mapping Reconstruction of Extended Sources

Three dimensional spectroscopy of extended sources is typically performed with dedicated integral field spectrographs. We describe a method of reconstructing full spectral cubes, with two spatial and one spectral dimension, from rastered spectral mapping observations employing a single slit in a traditional slit spectrograph. When the background and image characteristics are stable, as is often achieved in space, the use of traditional long slits for integral field spectroscopy can substantially reduce instrument complexity over dedicated integral field designs, without loss of mapping efficiency -- particularly compelling when a long slit mode for single unresolved source followup is separately required. We detail a custom flux-conserving cube reconstruction algorithm, discuss issues of extended source flux calibration, and describe CUBISM, a tool which implements these methods for spectral maps obtained with ther Spitzer Space Telescope's Infrared Spectrograph.Comment: 11 pages, 8 figures, accepted by PAS

SB9: The Ninth Catalogue of Spectroscopic Binary Orbits

The Ninth Catalogue of Spectroscopic Binary Orbits (http://sb9.astro.ulb.ac.be) continues the series of compilations of spectroscopic orbits carried out over the past 35 years by Batten and collaborators. As of 2004 May 1st, the new Catalogue holds orbits for 2,386 systems. Some essential differences between this catalogue and its predecessors are outlined and three straightforward applications are presented: (1) Completeness assessment: period distribution of SB1s and SB2s; (2) Shortest periods across the H-R diagram; (3) Period-eccentricity relation.Comment: Accepte for publication in A&A, 6 pages, 6 figure

The CORALIE survey for southern extra-solar planets VIII. The very low-mass companions of HD141937, HD162020, HD168443, HD202206: brown dwarfs or superplanets?

Doppler CORALIE measurements of the solar-type stars HD141937, HD162020, HD168443 and HD202206 show Keplerian radial-velocity variations revealing the presence of 4 new companions with minimum masses close to the planet/brown-dwarf transition, namely with m_2sin(i) = 9.7, 14.4, 16.9, and 17.5 M_Jup, respectively. The orbits present fairly large eccentricities (0.22<e<0.43). Except for HD162020, the parent stars are metal rich compared to the Sun, as are most of the detected extra-solar planet hosts. Considerations of tidal dissipation in the short-period HD162020 system points towards a brown-dwarf nature for the low-mass companion. HD168443 is a multiple system with two low-mass companions being either brown dwarfs or formed simultaneously in the protoplanetary disks as superplanets. For HD202206, the radial velocities show an additional drift revealing a further outer companion, the nature of which is still unknown. Finally, the stellar-host and orbital properties of massive planets are examined in comparison to lighter exoplanets. Observed trends include the need of metal-rich stars to form massive exoplanets and the lack of short periods for massive planets. If confirmed with improved statistics, these features may provide constraints for the migration scenario.Comment: 14 pages including figures, accepted for publication in A&

HD 80606 b, a planet on an extremely elongated orbit

We report the detection of a planetary companion orbiting the solar-type star HD 80606, the brighter component of a wide binary with a projected separation of about 2000 AU. Using high-signal spectroscopic observations of the two components of the visual binary, we show that they are nearly identical. The planet has an orbital period of 111.8 days and a minimum mass of 3.9 M_Jup. With e=0.927, this planet has the highest orbital eccentricity among the extrasolar planets detected so far. We finally list several processes this extreme eccentricity could result from.Comment: 4 pages, 1 figure included, submitted to A&A, final versio

Reprocessing the Hipparcos Intermediate Astrometric Data of spectroscopic binaries: II. Systems with a giant component

By reanalyzing the Hipparcos Intermediate Astrometric Data of a large sample of spectroscopic binaries containing a giant, we obtain a sample of 29 systems fulfilling a carefully derived set of constraints and hence for which we can derive an accurate orbital solution. Of these, one is a double-lined spectroscopic binary and six were not listed in the DMSA/O section of the catalogue. Using our solutions, we derive the masses of the components in these systems and statistically analyze them. We also briefly discuss each system individually.Comment: 15 pages, 25 figures, Accepted in A&

The CORALIE survey for southern extrasolar planets V: 3 new extrasolar planets

We report the detection of 3 new planetary companions orbiting the solar-type stars GJ 3021, HD 52265 and HD 169830 using radial-velocity measurements taken with the CORALIE echelle spectrograph. All these planetary companions have longer orbital periods than the 51 Peg-like objects. The orbits are fairly eccentric. The minimum masses of these planets range from 1 to 3.3 M_Jup. The stars have spectral types from F8V to G6V. They are metal-rich. We also present our radial-velocity measurements for three solar-type stars known to host planetary companions iota Hor (HD 17051), HD 210277 and HD 217107.Comment: 14 pages, 5 figures (included), A&A in press, a1sini unit corrected in table 6, Fig.3 correcte

New neighbours. III. 21 new companions to nearby dwarfs, discovered with adaptive optics

We present some results of a CFHT adaptive optics search for companions to nearby dwarfs. We identify 21 new components in solar neighbourhood systems, of which 13 were found while surveying a volume-limited sample of M dwarfs within 12pc. We are obtaining complete observations for this subsample, to derive unbiased multiplicity statistics for the very-low-mass disk population. Additionally, we resolve for the first time 6 known spectroscopic or astrometric binaries, for a total of 27 newly resolved companions. A fair fraction of the new binaries has favourable parameters for accurate mass determinations. The newly resolved companion of Gl120.1C had an apparent spectroscopic minimum mass in the brown-dwarf range (Duquennoy & Mayor 1991) and it contributed to the statistical evidence that a few percent of solar type stars might have close-in brown-dwarf companions. We find that Gl~120.1C actually is an unrecognised double-lined spectroscopic pair. Its radial-velocity amplitude had therefore been strongly underestimated by Duquennoy & Mayor, and it does not truly belong to their sample of single-lined systems with minimum spectroscopic mass below the substellar limit. We also present the first direct detection of Gl~494B, an astrometric brown-dwarf candidate. Its luminosity does straddle the substellar limit, and it is a brown dwarf if its age is less than 300Myr. A few more years of observations will ascertain its mass and status from first principles.Comment: Accepted by Astronomy & Astrophysic