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Ammonium salts are a reservoir of nitrogen on a cometary nucleus and possibly on some asteroids

Longobardo, Andrea; Palomba, Ernesto; Schmitt, Bernard +29 more

The measured nitrogen-to-carbon ratio in comets is lower than for the Sun, a discrepancy which could be alleviated if there is an unknown reservoir of nitrogen in comets. The nucleus of comet 67P/Churyumov-Gerasimenko exhibits an unidentified broad spectral reflectance feature around 3.2 micrometers, which is ubiquitous across its surface. On the …

Ammonium salts on comet 67P

Smith, Keith T.

Xenon isotopes in 67P/Churyumov-Gerasimenko show that comets contributed to Earth's atmosphere

Wurz, P.; Altwegg, K.; Balsiger, H. +27 more

The origin of cometary matter and the potential contribution of comets to inner-planet atmospheres are long-standing problems. During a series of dedicated low-altitude orbits, the Rosetta Orbiter Spectrometer for Ion and Neutral Analysis (ROSINA) on the Rosetta spacecraft analyzed the isotopes of xenon in the coma of comet 67P/Churyumov-Gerasimen…

Surface changes on comet 67P/Churyumov-Gerasimenko suggest a more active past

Jorda, L.; Lara, L. M.; Bertaux, J. -L. +53 more

The Rosetta spacecraft spent ~2 years orbiting comet 67P/Churyumov-Gerasimenko, most of it at distances that allowed surface characterization and monitoring at submeter scales. From December 2014 to June 2016, numerous localized changes were observed, which we attribute to cometary-specific weathering, erosion, and transient events driven by expos…

Rosetta’s comet 67P/Churyumov-Gerasimenko sheds its dusty mantle to reveal its icy nature

Jorda, L.; Lamy, P. L.; Bertaux, J. -L. +50 more

The Rosetta spacecraft has investigated comet 67P/Churyumov-Gerasimenko from large heliocentric distances to its perihelion passage and beyond. We trace the seasonal and diurnal evolution of the colors of the 67P nucleus, finding changes driven by sublimation and recondensation of water ice. The whole nucleus became relatively bluer near perihelio…

Seasonal exposure of carbon dioxide ice on the nucleus of comet 67P/Churyumov-Gerasimenko

Langevin, Y.; Bellucci, G.; Jaumann, R. +75 more

Carbon dioxide (CO₂) is one of the most abundant species in cometary nuclei, but because of its high volatility, CO₂ ice is generally only found beneath the surface. We report the infrared spectroscopic identification of a CO₂ ice-rich surface area located in the Anhur region of comet 67P/Churyumov-Gerasimenko. Spe…

Rosetta observes sublimating surface ices

Smith, Keith T.

Rosetta ends 2-year comet mission with final descent

Clery, Daniel

On the nucleus structure and activity of comet 67P/Churyumov-Gerasimenko

Bertaux, Jean-Loup; Da Deppo, Vania; Naletto, Giampiero +63 more

Images from the OSIRIS scientific imaging system onboard Rosetta show that the nucleus of 67P/Churyumov-Gerasimenko consists of two lobes connected by a short neck. The nucleus has a bulk density less than half that of water. Activity at a distance from the Sun of >3 astronomical units is predominantly from the neck, where jets have been seen c…

Dust measurements in the coma of comet 67P/Churyumov-Gerasimenko inbound to the Sun

Accolla, Mario; Altobelli, Nicolas; Bertaux, Jean-Loup +78 more

Critical measurements for understanding accretion and the dust/gas ratio in the solar nebula, where planets were forming 4.5 billion years ago, are being obtained by the GIADA (Grain Impact Analyser and Dust Accumulator) experiment on the European Space Agency’s Rosetta spacecraft orbiting comet 67P/Churyumov-Gerasimenko. Between 3.6 and 3.4 astro…