IUE observations of periodic comets Tempel-2, Kopff, and Tempel-1

We summarize the results of observations made between 10 Jun. - 18 Dec. 1988 with the International Ultraviolet Explorer (IUS) of comet P/Tempel-2 during its 1988 appearance. The derived water production rate and relative gas/dust ratio are compared with those of P/Halley, observed with IUE in 1985-86, and other potential Comet Rendezvous/Asteroid Flyby (CRAF) target comets, P/Kopff and P/Tempel-1, both observed with IUE in 1983

Twentieth century light curves and the nucleus of comet P/Tempel 2

Observations of P/Tempel 2 from 1899 to 1988 corresponding to 13 apparitions are analyzed in order to estimate the perihelion asymmetry of the gas production curve for different periods of its evolution. Using the correlation found by Festou et al. (1990) between the perihelion asymmetries and the delay in perihelion passage due to the action of nongravitational forces, we estimate the mass of the comet to be M approximately equals 1.6 plus or minus 0.5 x 10(exp 14) kg. Assuming a volume of 500 cu km, based on nuclear observations, a density of 0.3 plus or minus 0.1 g/cu cm is obtained

Heliocentric distance dependencies of the C2 lifetime and C2 parent production rate in comet P/Brorsen-Metcalf (1989o)

Comet P/Brorsen-Metcalf (1989o) has been extensively observed in the visible and in the ultraviolet during its latest apparition of summer 1989. In this paper we report a preliminary determination of the C2 production rates and lifetimes and we compare those rates to the H2O production rates obtained from UV data

The gas production rate of periodic comet d'Arrest

Comet P/d'Arrest is a potential target for a rendezvous mission to a short period comet. Its light curve is rather peculiar, the comet being active only after perihelion passage. One apparition out of two is easy to observe from the ground. The 1995 apparition of the comet will offer a unique opportunity to characterize the outgassing properties of its nucleus

Ultraviolet Spectroscopy of Comet 9P/Tempel 1 with Alice/Rosetta during the Deep Impact Encounter

We report on spectroscopic observations of periodic comet 9P/Tempel 1 by the Alice ultraviolet spectrograph on the Rosetta spacecraft in conjunction with NASA's Deep Impact mission. Our objectives were to measure an increase in atomic and molecular emissions produced by the excavation of volatile sub-surface material. We unambiguously detected atomic oxygen emission from the quiescent coma but no enhancement at the 10% (1-sigma) level following the impact. We derive a quiescent water production rate of 9 x 10^27 molecules per second with an estimated uncertainty of 30%. Our upper limits to the volatiles produced by the impact are consistent with other estimates.Comment: 11 pages, 4 postscript figures. Accepted for publication in Icarus special issue on Deep Impac

Radio Investigations Of 19p/Borrelly In Support To The Deep Space 1 Flyby

International audienc

Radio Investigations Of 19p/Borrelly In Support To The Deep Space 1 Flyby

International audienc

Alice—An ultraviolet imaging spectrometer for the Rosetta Orbiter

International audienceWe describe the design concept and scientific objectives of ALICE: a lightweight (2.2 kg), low-power (2.9 W), and low-cost UV imaging spectrometer for the ESA Rosetta Orbiter. Ultraviolet spectroscopy is a powerful tool for studying astrophysical objects, and has been applied with great success to the study of comets. ALICE is designed to obtain far-UV (FUV) spectra of the Rosetta comet nucleus and coma in the 700–2050 Å bandpass; it will achieve spectral resolutions between 9.8 and 12.5 Å across the bandpass for extended sources that fill its 0.1 × 6.0 deg.2 field-of-view. It employs an off-axis telescope feeding a 0.15-m normal incidence Rowland circle spectrograph with a concave holographic reflection grating. The imaging microchannel plate detector utilizes dual solar-blind opaque photocathodes (KBr and Csl) and a 2-D wedge-and-strip readout array. ALICE will deepen the Rosetta Orbiter remote sensing investigation through its ability to detect and measure (1) noble gases; (2) atomic abundances in the coma; (3) major ion abundances in the tail; and (4) production rates, variability, and structure of H2O and CO/CO2 molecules that generate cometary activity. In addition, ALICE will allow an investigation of the FUV properties of the nucleus and its solid grains, and can provide unique information during asteroid flybys and at en-route planetary encounters, most notably, Mars