The project “spice”

Proposed to both the French and the European Space Agency as one possible small mission, SPICE is a project for a dedicated small satellite for a near-IR spectroscopic all-sky survey. The instrument would cover the spectral range 1.8 - 3.6µm, possibly extended to 1.8 - 7µm, at a resolution of 100, with pixels of 1 arc-min. The excellent sensitivity (0.02 MJy sr-1) results from: i) the quasi-zero level of background due to the efficient passive cooling of the whole experiment; ii) the use of large format arrays; iii) the non-stop observing mode (drift-scanning). The spectral domain, complementing the one of ISO, partially opaque from the ground, is specially rich in spectral features tracing stars and all components of the Interstellar Medium (molecular, atomic and ionized gas, dust). With a cooling below 80 K of the focal instrument, then it becomes possible to consider doubling the spectral domain and to cover the whole 1.8 - 7µm range.     

The Exosolar Planets Program of the COROT satellite

Earth, Moon, and Planets -     

Adaptive Optics on a 3.6-Meter Telescope. The ADONIS System.

ADONIS is an adaptive optics (AO) user friendly instrument offered to the European astronomical community on the ESO 3.6-m telescope at La Silla. It is an upgraded version of COME-ON-PLUS, the VLT AO prototype, which already produced significative astrophysical results in a wide range of fields, from planetology to extragalactic astrophysics. ADONIS is now allowing the astronomer to use adaptive optics as a common user instrument thanks to the implementation of an open artificial intelligence software that handles the large number of parameters needed to optimise the AO correction. We will describe the ADONIS system, including the two dedicated infrared cameras, summarize its performances and discuss the observing procedures.     

DENIS: A deep near-infrared survey of the southern sky

The DENIS project is the first attempt to carry out a complete digitized survey of the southern sky in the range 1–2.5µm. The main objectives of the programme and the main specifications of the camera and of the data processing stream are briefly outlined     

Transiting exoplanets from the CoRoT space mission Resolving the nature of transit candidates for the LRa03 and SRa03 fields

CoRoT is a space telescope which aims at studying internal structure of stars and detecting extrasolar planets. We present here a list of transits detected in the light curves of stars observed by CoRoT in two fields in the anti-center direction: the LRa03 one observed during 148 days from 3 October 2009 to 1 March 2010 followed by the SRa03 one from the 5 March 2010 to the 29 March 2010 during 25 days. 5329 light curves for the LRa03 field and 4169 for the SRa03 field were analyzed by the detection team of CoRoT. Then some of the selected exoplanetary candidates have been followed up from the ground. In the LRa03 field, 19 exoplanet candidates have been found, 8?remain unsolved. No secured planet has been found yet. In the SRa03 field, there were 11 exoplanetary candidates among which 6 cases remain unsolved and 3 planets have been found: CoRoT-18b, CoRoT-19b, CoRoT-20b.     

First results obtained with DENIS

We briefly report on the first astronomical results obtained with the DENIS camera at the ESO 1 meter telescope.     

Study of the Ammonia ice cloud layer in the equatorial region of Jupiter from the infrared interferometric experiment on voyager

Spectra from the Voyager 1 infrared interferometer spectrometer (IRIS) obtained near the time of closest approach to Jupiter were analyzed for the purpose of inferring ammonia cloud properties associated with the Equatorial Region. Comparisons of observed spectra with synthetic spectra computed from a radiative transfer formulation, that includes multiple scattering, yielded the following conclusions: (1) very few NH₃ ice particles with radii less than 3 μm contribute to the cloud opacity; (2) the major source of cloud opacity arises from particles with radii in excess of 30 μm; (3) column particle densities are between 1 and 2 orders of magnitude smaller than those derived from thermochemical considerations alone, implying the presence of important atmospheric motion; and (4) another cloud system is confirmed to exist deeper in the Jovian troposphere.     

PEGASE, an infrared interferometer to study stellar environments and low mass companions around nearby stars

PEGASE is a mission dedicated to the exploration of the environment (including habitable zone) of young and solar-type stars (particularly those in the DARWIN catalogue) and the observation of low mass companions around nearby stars. It is a space interferometer project composed of three free flying spacecraft, respectively featuring two 40 cm siderostats and a beam combiner working in the visible and near infrared. It has been proposed to ESA as an answer to the first “Cosmic Vision” call for proposals, as an M mission. The concept also enables full-scale demonstration of space nulling interferometry operation for DARWIN.

Stellar occultations by two comets: IRAS-Araki-Alcock (1983d) and P/IRAS (1983j)

A stellar appulse of comet 1983d was observed in 1983 May 08.956 using a video photometry technique. Although the miss distance did not exceed 420 ± 50 km no significant absorption was detected. Another close appulse, of comet 1983j this time, was measured with a photoelectric photometer on 1983 September 14.036. A small feature of the lightcurve, only 1.8% deep, could be attributed to dust surrounding the nucleus within a 350-km radius. The deduced dust ejection rate is 6 × 10⁶ g/sec.     

Far-infrared photometry of planets: Saturn and Venus

We present far-infrared observations of Saturn and Venus made within four spectral bands (31 to 38, 47 to 67, 71 to 94, and 114 to 196 μm) using a 32-cm airborne telescope during May 1977. The set of brightness temperatures obtained from Saturn is analyzed on the basis of thermal models of the atmosphere of this planet. The best agreement is obtained with an effective temperature of about 95°K for the planet itself and a ring contribution corresponding to brightness temperatures ranging from 55 to 70°K. These values of the temperature of the ring system are smaller than the ones measured at shorter wavelengths and could be indicative of a decreasing emissivity of the rings in the far infrared.