sábado, 26 de octubre de 2013
This image of spectrum of instrument NIRSPEC KECK TELESCOPE , from comet C/2012 S1 ISON , date 25/10/2013 , Waveblue 2,13 microns , Wavered 4.23 microns , belongs from program '' Measuring volatiles abundances , D/H ratios , and spin temperatures in comet C/2012 S1 ISON '' , below project and research , COMETARY INVESTIGATION ASTROPHYSIC GROUP FB . CREDIT : "This research has made use of the Keck Observatory Archive (KOA), which is operated by the W. M. Keck Observatory and the NASA Exoplanet Science Institute (NExScI), under contract with the National Aeronautics and Space Administration." Please also acknowledge the PI(s) of datasets that have been obtained through KOA. The Keck Observatory Archive (KOA) is a collaboration between the NASA Exoplanet Science Institute (NExScI) and the W. M. Keck Observatory (WMKO). NExScI is sponsored by NASA's Origins Theme and Exoplanet Exploration Program, and operated by the California Institute of Technology in coordination with the Jet Propulsion Laboratory (JPL).
domingo, 20 de octubre de 2013
Within the framework of cooperation of the draft study and research of comet C/2012 S1 ISON the astrophysicist, and member of the Investigation Cometary FB Astrophysic Jian-Yang Li | Planetary Science Institute, has published some scientific results of astronomical research comet C / 2012 S1 ISON : 1.- The dust coma is mostly composed of sub-µm-sized particles emitted at speeds of tens of meters per second. 2.- The A(θ)fρ, a quantity to measure the dust production rate, is 1339 and 1239 cm in the F606W and F438W filters, respectively, in apertures <1.6″ in radius. 3.- The dust colors are slightly redder than solar, with a slope of 5.0±0.2% per 100 nm, and increase to >10% per 100 nm 10,000 km down the tail. The color properties of ISON’s coma is similar to that of Comet Hale-Bopp. A sunward jet is about 1.6″ long, at a position angle of 291°, with an opening angle of ~45º. The shape and orientation of the jet does not change over 19 hours of our observations, suggesting a circumpolar jet. The jet indicates that the rotation pole is pointing within 30° of (RA, Dec) = (330°, 0°). There are two interesting implications from our observation: The existence of ice grains in the inner coma is the best explanation we could find for the change of color within the coma. The comet always faces the Sun with one side, and the other side is always in dark, therefore probably still retaining abundant supervolatiles (CO and/or CO2). This situation won’t change until the last week before perihelion. When the original night side is suddenly exposed to strong sunlight at within Mercury’s orbit, large outbursts might be triggered. While we are continuing our analysis, we were able to put an upper limit of the radius of the nucleus as 2 km from our images. The top image is the image of ISON taken by Hubble on October 9. The bottom image is an enhancement to reveal the non-symmetric structures in the coma, such as jet. Credit: NASA/ESA/Z. Levay The real color of comet ISON :
sábado, 12 de octubre de 2013
The author , J.P.Navarro , analyzes the 3589 ccd's observations from MPC database and obtained the new and the best light ccd curve for this comet , C/2012 S1 ISON , adjust the principal light ccd curve based in 3.589 observations ccd's and calculated for the differential analysis , two new photometricals laws , the best adjust is new mathematical method for the analysis , based in polynomial regression , the old method of calculation based in linear regression , donot fit properly , the new method of polynomial regression in order 2 or 3 correctly whether all points of the curve, in particular the kite has a curvature characteristic in its data get three new Photometric parameters, a, b1 and b2, the author has been linked to with absolute magnitude (m0) and b1 and b2 are new indicators of internal activity of the comet , the absence of more new settings for all curve data, the results indicate a deceleration typical brightness of new comets oort cloud, most likely due to a change in the main volatile component of the gas and dust sublimation the comet, this change occurred in 1.4 < r < 2.4 au . Reference : ''Estimates of masses , volumes , and densities of short-period comet nuclei'' , H.Rickman et at. 1987 .
miércoles, 9 de octubre de 2013
Scientists are unraveling more information on Comet C/2012 S1 (ISON) as it continues on its journey toward the Sun. Comet C/ISON will skim 730,000 miles above the Sun’s surface on Nov. 28 and has the potential to be readily visible from Earth starting in early December. “We measured the rotational pole of the nucleus. The pole indicates that only one side of the comet is being heated by the Sun on its way in until approximately one week before it reaches it closest point to the Sun,” said Planetary Science Institute Research Scientist Jian-Yang Li, who led a team that imaged the comet. “Since the surface on the dark side of the comet should still retain a large fraction of very volatile materials, the sudden exposure to the strong sunlight when it gets closer to the Sun than Mercury could trigger huge outbursts of material,” Li said. Li presented the findings today at the American Astronomical Society’s Division for Planetary Sciences 45th Annual Meeting in Denver. Comet C/ISON was imaged with the Hubble Space Telescope using the Wide Field Camera 3 on April 10. “We measured the color of the coma, and found that the outer part of the coma is slightly redder than the inner part,” Li said. “This color change is unusual in comets, and seems to imply that the inner part contains some water ice grains, which sublimate as they move away from the nucleus.” Comet C/ISON was discovered in September 2012 when it was farther away from the Sun than Jupiter, and was already active at such a great distance. This is distinct from most other sungrazers – comets that pass extremely close to the sun – that are only discovered and remain visible for at most several days when nearest the Sun. At such a close perihelion distance from the Sun, sungrazers are expected to be intensely heated by the Sun, and sublimate not only ice but also silicates and even metals, releasing a tremendous amount of dust. The expectation is high that Comet C/ISON will be much brighter and more spectacular than most other sungrazers when it puts on a show late this year. “As a first-time visitor to the inner solar system, Comet C/ISON provides astronomers a rare opportunity to study a fresh comet preserved since the formation of the Solar System,” Li said. “The expected high brightness of the comet as it nears the Sun allows for many important measurements that are impossible for most other fresh comets.” NASA and the Space Telescope Science Institute funded the project. Research Planetary Science Institute Research Scientist Jian-Yang Li , member of Cometary Investigation Astrophysic Group FB ( J.P. Navarro Pina , Administrator CIAG_FB ) This image shows the color change of Comet C/ISON's dust coma. The white dot at the center of the coma marks the location of the nucleus. ISON's dust coma appears to be less red near the nucleus than it is further away from the nucleus. Although the color change is actually very small, it could be an indication of relatively more water ice particles near the nucleus. Those icy particles evaporate, as they move outward, makes the coma appear redder. Credit: NASA, ESA, J.-Y. Li (Planetary Science Institute) and Hubble Comet ISON Imaging Science Team.
domingo, 6 de octubre de 2013
The current photometrical visual model of comet ISON show ~ 1.5 - 2 visuals magnitudes below the theorical my photometric model is based only on visual observations, my previous calculations of the dust production rate confirmed that the comet will not be as bright as expected, compute a maximum visual magnitude is very risky
My second analysis of the light curve of comet C / 2021 A1 LEONARD, indicates in T-300, a stagnation in the rate of increase in brightness ...