domingo, 25 de noviembre de 2018
This new article in Astrophysical journal is quite consistent with the hypothesis that I have been mentioning for several weeks ... comment on the possibility of being in front of a new type of '' comet '' never observed in our solar system, the explanation is based on It deals with an icy body that has been eons traveling among the stars suffering above all the "erosion" of cosmic rays on its surface, leaving a new type of very reflective ice that has never been observed before in a comet, in this way, we can also Explain the non-gravitational accelerations observed. Abstract 1I/'Oumuamua is the first confirmed interstellar body in our solar system. Here we report on observations of 'Oumuamua made with the Spitzer Space Telescope on 2017 November 21–22 (UT). We integrated for 30.2 hr at 4.5 μm (IRAC channel 2). We did not detect the object and place an upper limit on the flux of 0.3 μJy (3σ). This implies an effective spherical diameter less than [98, 140, 440] m and albedo greater than [0.2, 0.1, 0.01] under the assumption of low, middle, or high thermal beaming parameter η, respectively. With an aspect ratio for 'Oumuamua of 6:1, these results correspond to dimensions of [240:40, 341:57, 1080:180] m, respectively. We place upper limits on the amount of dust, CO, and CO2 coming from this object that are lower than previous results; we are unable to constrain the production of other gas species. Both our size and outgassing limits are important because 'Oumuamua's trajectory shows non-gravitational accelerations that are sensitive to size and mass and presumably caused by gas emission. We suggest that 'Oumuamua may have experienced low-level post-perihelion volatile emission that produced a fresh, bright, icy mantle. This model is consistent with the expected η value and implied high-albedo value for this solution, but, given our strict limits on CO and CO2, requires another gas species—probably H2O—to explain the observed non-gravitational acceleration. Our results extend the mystery of 'Oumuamua's origin and evolution. Published Spitzer Observations of Interstellar Object 1I/'Oumuamua David E. Trilling1,2, Michael Mommert1,2, Joseph L. Hora3, Davide Farnocchia4, Paul Chodas4, Jon Giorgini4, Howard A. Smith3, Sean Carey5, Carey M. Lisse6, Michael Werner4Show full author list Published 2018 November 14 The Astronomical Journal, Volume 156, Number 6
jueves, 8 de noviembre de 2018
The recent analysis update of light visual curve based in COBS DATABASE , obtained visual magnitud maximum of m1=+3.5 data 17/ December 2018 , based next photometricals parameters m0=8.9 and activity index n=9.9 this calculations based in classic formula for predicted visual magnitude : m1 = m0 + 5 log ( delta ) + n log ( R )
Comet C / 2021 A1 Leonard shows at the moment with 272 ccd observations a linear fit in its light curve, the provisional photometric parame...