6 research outputs found
Dust observations of Comet 9P/Tempel 1 at the time of the Deep Impact
On 4 July 2005 at 05:52 UT, the impactor of NASA's Deep Impact (DI) mission
crashed into comet 9P/Tempel 1 with a velocity of about 10 km/s. The material
ejected by the impact expanded into the normal coma, produced by ordinary
cometary activity.
The characteristics of the non-impact coma and cloud produced by the impact
were studied by observations in the visible wavelengths and in the near-IR. The
scattering characteristics of the "normal" coma of solid particles were studied
by comparing images in various spectral regions, from the UV to the near-IR.
For the non-impact coma, a proxy of the dust production has been measured in
various spectral regions. The presence of sublimating grains has been detected.
Their lifetime was found to be about 11 hours. Regarding the cloud produced by
the impact, the total geometric cross section multiplied by the albedo was
measured as a function of the color and time. The projected velocity appeared
to obey a Gaussian distribution with the average velocity of the order of 115
m/s. By comparing the observations taken about 3 hours after the impact, we
have found a strong decrease in the cross section in J filter, while that in Ks
remained almost constant. This is interpreted as the result of sublimation of
grains dominated by particles of sizes of the order of some microns.Comment: Accepted by A&
Broad- and narrowband visible imaging of comet 9P/Tempel 1 at ESO around the time of the Deep Impact event
Ethnic Pride, Traditional Family Values, and Acculturation in Early Cigarette and Alcohol Use Among Latino Adolescents
Deep Impact: observations from a worldwide Earth-based campaign
peer reviewedOn 4 July 2005, many observatories around the world and in space observed the collision of Deep Impact with comet 9P/Tempel 1 or its aftermath. This was an unprecedented coordinated observational campaign. These data show that (i) there was new material after impact that was compositionally different from that seen before impact; (ii) the ratio of dust mass to gas mass in the ejecta was much larger than before impact; (iii) the new activity did not last more than a few days, and by 9 July the comet's behavior was indistinguishable from its pre-impact behavior; and (iv) there were interesting transient phenomena that may be correlated with cratering physics