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[Centaur]

Comet C/2010 X1 Elenin is still headed our way. Its orbital eccentricity has most recently been calculated as 1.00058, which is hyperbolic but only slightly greater than parabolic. So it is apparently not periodic (non-returning), although that determination could change due to perturbations and more observational data. Its orbital plane is inclined only 1.841° to the Earth’s current ecliptic plane.

Utilizing the latest JPL orbital elements (which are subject to change), I calculate that the comet will be in opposition (maximum angular solar elongation) to Sun on 2011 MAR 14 at a distance of 2.103 AU (astronomical units) from Earth. It will reach perihelion (closest to Sun) on SEP 10 at 0.481 AU from Sun. It will be at its ascending node passing northward through the ecliptic plane on SEP 14. It will be in inferior conjunction (minimum angular solar elongation) between Sun and Earth on SEP 26 while appearing to pass 1.8° north of Sun. It will be at perigee (closest to Earth) on OCT 16 at 0.242 AU.

Utilizing equatorial coordinates of current date, during its time in the inner solar system the comet will reach a maximum southern declination of 5.6° on SEP 09, and a maximum northern declination of 30.7° on October 29.

Utilizing JPL’s most recent magnitude parameters, the comet will be at magnitude +16.7 while in opposition on MAR 14. Its greatest brilliance would be expected at magnitude +6.0 on SEP 19. JPL admits that its magnitude slope parameter is merely assumed. I suspect it is somewhat conservative. The IAU is still predicting a peak magnitude of +3.8 during that same time frame.

I’ve created five charts related to Comet Elenin and its upcoming apparition. They can be seen at www.curtrenz.com/comets

Photos and descriptions of the comet would be welcome additions to this thread.

[Centaur]

I’ve created an animation demonstrating the movement of Comet Elenin and the Earth as seen from north of the ecliptic plane during 2011 JUL 22 to NOV 08. It can be seen at www.curtrenz.com/comets

[Centaur]

Sorry, but this comet might turn out to be a bust. I’ve updated my graphics to comply with the March 16th JPL orbital solution: www.curtrenz.com/comets . That results in a prediction for greatest brilliance of magnitude +8.4 on October 4th. However, the IAU is still sticking with its magnitude +3.8 prediction. It’s expected to pass 0.234 AU from Earth on October 16th, which is similar to the distance to Venus every 1.6 years.

Nevertheless, woo woos on the conspiracy message boards fear it is Planet X/Nibiru coming to collide with Earth. My website analytics tell me that I’ve been getting a huge number of hits to my comet graphics from those sites, despite my never posting there. Many of those folks simply look at a 2-D diagram and notice that the orbits seem to intersect. In 3-D they do not, and the two bodies do not arrive at the 2-D point of intersection at the same time.

[Centaur]

JPL updated its Comet Elenin orbital solution yesterday, and that is now reflected in my graphics. Although you will probably not notice any changes. The updates are becoming insignificant as the orbital parameters seem to have gotten pretty much nailed down. The heliocentric osculating value for the eccentricity at a nearby epoch is still shown as slightly more than 1.0, but the eccentricity is less than 1.0 if calculated for a distant epoch relative to the solar system barycenter. In other words, in the long run the orbit is elliptical with an orbital period of nearly 12,000 years. My updated graphics can be seen at: www.curtrenz.com/comets

[yadran]

Mar 17, 2011 19:51:09 GMT -6 Centaur said:

Sorry, but this comet might turn out to be a bust. I’ve updated my graphics to comply with the March 16th JPL orbital solution: www.curtrenz.com/comets . That results in a prediction for greatest brilliance of magnitude +8.4 on October 4th. However, the IAU is still sticking with its magnitude +3.8 prediction. It’s expected to pass 0.234 AU from Earth on October 16th, which is similar to the distance to Venus every 1.6 years.

Nevertheless, woo woos on the conspiracy message boards fear it is Planet X/Nibiru coming to collide with Earth. My website analytics tell me that I’ve been getting a huge number of hits to my comet graphics from those sites, despite my never posting there. Many of those folks simply look at a 2-D diagram and notice that the orbits seem to intersect. In 3-D they do not, and the two bodies do not arrive at the 2-D point of intersection at the same time.

Hi, I am not many of those folks however I wish to see a diagram that shows Elenin in perspective projection, once it comes closer to Earth.
Also, the comet was visible in the last December and some photos are circulating the web. Since then no new pictures of it are available. I found it very odd, because the comet is closer now that it was then, So why no new pictures and more data about it?
Thank you

[Centaur]

Mar 25, 2011 14:02:32 GMT -6 yadran said:

Hi, I am not many of those folks however I wish to see a diagram that shows Elenin in perspective projection, once it comes closer to Earth.
Also, the comet was visible in the last December and some photos are circulating the web. Since then no new pictures of it are available. I found it very odd, because the comet is closer now that it was then, So why no new pictures and more data about it?
Thank you

Welcome to the discussion group, yadran. Apparently you are only looking at my diagrams that display views from well north of the ecliptic plane (Earth’s orbital plane). My other four diagrams are from an earthbound observer’s perspective. Combining them in your mind may give you a better idea of what will be happening. The tiny comet will only come as close to Earth as Venus often does.

Please note that in my views from north of the ecliptic plane, the ascending node is plotted. That is the point where the comet will move from the southern side of the ecliptic plane to its northern side. My animated graphic displays the comet’s distance north or south of the ecliptic plane. That distance is zero when the comet intersects the ascending node. When the comet does pass near the Earth’s orbit, it will be far north of the Earth’s orbit and arrive long before the Earth will. FYI, an AU is the average distance between the Earth and Sun, i.e. about 150,000,000 km or 93,000,000 mi.

In my similar thread at Cloudy Nights, Sharkman contributed two photos of the comet that he took on March 13: www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Board/planets/Number/4381243/page/0/view/collapsed/sb/5/o/o/fpart/all . As I noted earlier, the comet appears to be a disappointment regarding size and brightness, thus interest has dwindled within the astronomical community. It’s only on woo woo websites that the fearful and credulous remain excited.

Regarding data, JPL updates its orbital solution about once a week: ssd.jpl.nasa.gov/sbdb.cgi#top . I try to update my graphics shortly afterward.

[yadran]

Mar 25, 2011 14:32:09 GMT -6 Centaur said:

Mar 25, 2011 14:02:32 GMT -6 yadran said:

Hi, I am not many of those folks however I wish to see a diagram that shows Elenin in perspective projection, once it comes closer to Earth.
Also, the comet was visible in the last December and some photos are circulating the web. Since then no new pictures of it are available. I found it very odd, because the comet is closer now that it was then, So why no new pictures and more data about it?
Thank you

Welcome to the discussion group, yadran. Apparently you are only looking at my diagrams that display views from well north of the ecliptic plane (Earth’s orbital plane). My other four diagrams are from an earthbound observer’s perspective. Combining them in your mind may give you a better idea of what will be happening. The tiny comet will only come as close to Earth as Venus often does.

Please note that in my views from north of the ecliptic plane, the ascending node is plotted. That is the point where the comet will move from the southern side of the ecliptic plane to its northern side. My animated graphic displays the comet’s distance north or south of the ecliptic plane. That distance is zero when the comet intersects the ascending node. When the comet does pass near the Earth’s orbit, it will be far north of the Earth’s orbit and arrive long before the Earth will. FYI, an AU is the average distance between the Earth and Sun, i.e. about 150,000,000 km or 93,000,000 mi.

In my similar thread at Cloudy Nights, Sharkman contributed two photos of the comet that he took on March 13: www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Board/planets/Number/4381243/page/0/view/collapsed/sb/5/o/o/fpart/all . As I noted earlier, the comet appears to be a disappointment regarding size and brightness, thus interest has dwindled within the astronomical community. It’s only on woo woo websites that the fearful and credulous remain excited.

Regarding data, JPL updates its orbital solution about once a week: ssd.jpl.nasa.gov/sbdb.cgi#top . I try to update my graphics shortly afterward.

Thank you for this quick answer.
Comet will not collide with Earth of course, this is not something I am worrying if I do at all, but the tail. We will certainly pass through it's tail?!
And regarding the size. No one knows it's real size, or I'm missing something here?
Also about the coma. Some claims that it's rather small. Comet's coma is everything but not small, well if we shall believe to this gustavomuler.fotografiaastronomica.com/www/images/cometas/C1010X1/C2010X1-110307-J47c.avi.gif
I do not see any photos on the link/forum you have provided?

Thx!

[Paulie pchris00]

If the comet is passing well north of Earth's orbit, then the tail will also pass north of Earth's orbit. Any debris melting off the coma will continue in an orbit similar to the comet. I don't know the mathematics of it like Centaur, but the tail material shouldn't be losing much angular momentum, and should therefore follow roughly the same orbit as Elenin. I don't expect any meteor showers out of this comet.

[Centaur]

Mar 25, 2011 17:11:58 GMT -6 yadran said:

Thank you for this quick answer.
Comet will not collide with Earth of course, this is not something I am worrying if I do at all, but the tail. We will certainly pass through it's tail?!
And regarding the size. No one knows it's real size, or I'm missing something here?
Also about the coma. Some claims that it's rather small. Comet's coma is everything but not small, well if we shall believe to this gustavomuler.fotografiaastronomica.com/www/images/cometas/C1010X1/C2010X1-110307-J47c.avi.gif
I do not see any photos on the link/forum you have provided?

Thx!

You’re welcome, yadran. Leonid Elenin, the discoverer, estimates the comet is three to four kilometers in diameter. Any tail that such a tiny comet might develop would come nowhere near the Earth. The photos in my link to that Cloudy Nights thread are in posts #17 & #20 by Sharkman in New Zealand. Perhaps one must become a member for the photos to appear. In any event, Sharkman also posted this YouTube link within his post #20: www.youtube.com/watch?v=6rwdXazucGo. The photos would not be found through my link to the JPL data.

[Centaur]

Mar 25, 2011 17:33:06 GMT -6 Paulie pchris00 said:

If the comet is passing well north of Earth's orbit, then the tail will also pass north of Earth's orbit. Any debris melting off the coma will continue in an orbit similar to the comet. I don't know the mathematics of it like Centaur, but the tail material shouldn't be losing much angular momentum, and should therefore follow roughly the same orbit as Elenin. I don't expect any meteor showers out of this comet.

You are quite correct, Paulie. Thank you for chiming in. You are becoming quite a celestial mechanic.

[yadran]

Mar 25, 2011 17:33:41 GMT -6 Centaur said:

Mar 25, 2011 17:11:58 GMT -6 yadran said:

Thank you for this quick answer.
Comet will not collide with Earth of course, this is not something I am worrying if I do at all, but the tail. We will certainly pass through it's tail?!
And regarding the size. No one knows it's real size, or I'm missing something here?
Also about the coma. Some claims that it's rather small. Comet's coma is everything but not small, well if we shall believe to this gustavomuler.fotografiaastronomica.com/www/images/cometas/C1010X1/C2010X1-110307-J47c.avi.gif
I do not see any photos on the link/forum you have provided?

Thx!

You’re welcome, yadran. Leonid Elenin, the discoverer, estimates the comet is three to four kilometers in diameter. Any tail that such a tiny comet might develop would come nowhere near the Earth. The photos in my link to that Cloudy Nights thread are in posts #17 & #20 by Sharkman in New Zealand. Perhaps one must become a member for the photos to appear. In any event, Sharkman also posted this YouTube link within his post #20: www.youtube.com/watch?v=6rwdXazucGo. The photos would not be found through my link to the JPL data.

Apparently it's not that thiny anymore: www.cloudynights.com/ubbthreads/showflat.php/Cat/0/Number/4381243/page/0/view/collapsed/sb/5/o/o/fpart/2/vc/1

[Centaur]

Thank you for your update, yadran. JPL currently estimates Comet Elenin’s absolute magnitude (H) as 12.0: ssd.jpl.nasa.gov/sbdb.cgi#top . In the IAU table provided in your linked post, that corresponds to an estimated diameter of between 7 and 24 km. The tail extends from the comet in the opposite direction of the Sun. When the comet is between Earth and Sun on September 10, it will be more than 0.5 AU from Earth. Any tail would not likely reach us, and even if it did it would be so tenuous as to be meaningless regarding physical effects. When the comet is closest to Earth at 0.23 AU on October 16, it will be well north of the ecliptic plane and so will its tail. In 1910 there was widespread paranoia in anticipation of the Earth moving through Comet Halley’s tail. Indeed the Earth moved through the tenuous tail but with no measurable effects. I would not worry about Comet Elenin.