An example of this came this week when a correspondent asked me about my observations of comet 2010 X1 Elenin . One of the prominent internet memes going around at the moment is that Elenin is actually the Moon of a Brown Dwarf star or a Brown Dwarf star itself (often claimed to be 4 times Jupiter’s size). I was asked if I could look out for something dim close to Elenin. There is just one problem, a Brown Dwarf close to Elenin would be very bright. Elenin currently is just outside the orbit of Mars (visualised in Celestia, click images to enlarge)
Brown Dwarf stars are stars that have only a few times the mass and radius of Jupiter; they are too small to start hydrogen fusion, although they may run for a short while on deuterium fusion. They are typically quite cool compared to main sequence stars, and emit very little visible light.
From a distance of a few light years or more they are invisible to optical telescopes. To find these dim almost-stars, we need to look with infrared sensitive telescopes. For example the WISE telescope had as one of its missions surveying for Brown Dwarfs. The coolest Brown Dwarf so far discovered by WISE is WISEPC J045853.90+643451.9 which is over 18 light years away. With a temperature of 600 K it is hot enough to melt lead and tin, but is totally invisible to our current optical telescopes.
But while these almost stars produce very little visible light of their own, they reflect light perfectly well. If you go out in the early morning and look to the north-east, you will see a bright object well above the horizon (brighter Venus is well below it). That is Jupiter, a failed Brown-Dwarf, which we can see just fine.
Elenin is currently just outside Mars’s orbit, we can easily calculate how bright an object 4 times Jupiter’s size would be at that distance using the formulas here. I’ve put my calculations up on Google Docs for people to play with (click this link for access to spreadsheet ).
Simulation of what a Brown Dwarf would look like in the sky tonight if it was near comet Elenin’s current position. I’ve used Stellarium’s cometary body codes, using a dark, non-luminous object with 4 times Jupiter’s diameter. It would be kind of obvious. If a Brown Dwarf with a surface much darker than the Moon was at Elenin’s distance (as of June 1), it would have a magnitude of -6.5.
This is much brighter than Venus, bright enough to cast shadows at night and bright enough to be easily seen in daylight. This is an under estimate, as a Brown Dwarf would be more likely to be more reflective, more like Jupiter. An object 4 times Jupiter’s size just outside Mars’s orbit would also be visible as a small disk (you can do the calculations for this one as an exercise for yourselves, see the Stellarium simulation above).
Simulating a non-self luminous Brown Dwarf using fruit. The granny smith apple is the Brown dwarf. Left hand panel, the Brown Dwarf at Pluto’s orbit. Right hand panel, the brown Dwarf at Mars’s orbit. The mandarin is Jupiter, the lillypilli pit is Mars and and the lillypilliy (closest to torch) is Earth. Distances have been scaled at 10 cm= I AU.
Brown Dwarfs are only invisible to us because they lie deep in the vasty dark, away from any light sources that can illuminate them. This is what causes confusion for some folks. Brown Dwarfs themselves produce little or no visible light but they are perfectly capable of reflecting light, as does Jupiter.
Here’s a test you can do yourself with a torch an some pieces of fruit. I’ve scaled the solar system so that 1 AU (the distance from Earth to the Sun) is 10 cm from the torch I’m using as the Sun. Mars’s orbit lies 25 cm away, Jupiter’s orbit is 62 cm away and Pluto’s orbit is 4 meters away. The orbit of the hypothetical planet Tyche would be two blocks away, and the nearest star, Proxima Centauri, lies 2.7 km away on the other side of Taperoo. I’ve used a lillypilli for Earth, a mandarin for Jupiter and an apple for a Brown Dwarf (see diagram above).
Strictly speaking, if I wanted to scale the diameters of the planets to the scale of the solar system, then I would have used 1 meter for 1 AU, them the Brown Dwarf would be 2 mm in diameter (I leave it as an exercise for the reader to test this themselves).
As you can see, when the non-self luminous “Brown Dwarf” is at Pluto’s distance, it is fairly dim, but when we move the “Brown Dwarf” to just outside of Mars’s orbit, it is quite bright. The atmosphere of a real T class is probably as reflective as a Granny Smith (but more a Magenta colour). Such an object would be readily visible in the night sky.
Leonid Elenin himself has done a simulation on his website (SpaceObs.org) of what would happen to solar system orbits if a Brown Dwarf passed through. It would be quite obvious.
What if we replace comet C/2010 X1 (Elenin) by brown dwarf with mass about 0.05 of Solar mass? This video demonstrate time interval from 2000 to 2020 years. As you can see, dramatic changes in the orbit of Saturn would have started 3 years ago. But at this time all planets are on it’s nominal orbits. I think myth about “brown dwarf instead comet Elenin” is debunked. You can see that by yourself.
Numerical integration was carried out by ORSA software using RADAU15-th order integrator.
Summary: So, as you can see, it is impossible for Elenin to be a moon of a Brown Dwarf star (also we would have noticed its orbital motion by now) or a Brown Dwarf itself.
 Obligatory Douglas Adams homage, with added AC/DC.
 I haven’t got any yet, either I’ve got the time wrong and the comet has set, or the observatory is closed because of bad weather.
 Note that for the H calculation Do is in Km, but for the magnitude calculation, Do is in AU. The calculated magnitudes of Venus, Jupiter and Neptune agree with their observed magnitudes.
Mr. Elenin is an amateur astronomer from Lubertsy City, Russia, near Moscow. He is a graduate of the Moscow Aviation Institute, works as a researcher at the Keldysh Institute of Applied Mathematics (Russian Academy of Sciences), is married, and is bilingual (Russian and English). He volunteers with the International Astronomical Search Collaboration, and runs a website at http://SpaceObs.org. He has had a passion for astronomy since childhood, and studies minor Solar System objects and variable stars. He has discovered more than 10 variable stars and numerous asteroids, and now, a comet.
On December 11th, 2010, Leonid Elenin posted news on his site of a “new and interesting object” discovered during a “routine survey of the sky on Dec. 10, 2010”. The discovery was made at the independent Russian remote observatory ISON-NM, which is located near Mayhill, New Mexico. The observatory is operated under the Russian project ISON (International Scientific Optical Network). His observations were confirmed by Aleksei Sergeyev and Artyom Novichonok at Madinak Observatory in the Ukrane.
Initially the comet was thought to be a short period comet, with aphelion near the orbit of Jupiter, and a perihelion inside the orbit of Earth. However, over a week after its discovery, the Minor Planets Center at Harvard published the orbital elements, revealing that the perihelion would be near Mercury! It was still unclear as to whether this was a rogue (a one time event) or a periodic comet. Further observations and calculations show that its period is on the order of 10,000 years, and that this is likely its first pass through the inner solar system. This leads to the prospect of a very bright comet in 2011. Leonid Elenin also estimates that the comet nucleus is 3-4 km in diameter.
According to the JPL Small Body Database C/2010 X1 is a Hyperbolic Comet, meaning that it will not return. However, Leonid Elenin has calculated that due to perturbations to the comet’s orbit from the gas giant planets, that the orbit of his comet will be modified to a long-period elliptical orbit, and that it will return in about 10,000 years.
Comet Elenin is in an orbit that is close to the plane of the ecliptic. It is currently just past opposition and about 3 times farther away from us than we are from the sun. Here is an illustration of the comet’s orbit as of April 5, 2011.
By September 1st, 2011, Comet Elenin will approach the orbit of Mercury, and it will reach Perhelion on September 5th. In just a little over a month it will have traveled from the orbit of the Earth to the Orbit of Mercury. At this point it will be so close to the sun from our vantage point that it will be completely hidden. However, it will be visible on solar-observing spacecraft such as STEREO and SOHO.
Instead of being excited about the possibility of a naked-eye visible comet, some people are making some very strange and wild claims about the comet, or about Leonid Elenin. Some people are apparently questioning whether Leonid Elenin is even a real person, despite the fact that he is acknowledged as a contributor in various scholarly journal articles since 2009.
Elenin will not collide with Earth.
At its closest approach, Comet Elenin will be 34 million kilometers (21 million miles) away from the Earth. It will also be 4 million kilometers (2.4 million miles) above the orbit of the Earth. See this image showing that Elenin will be well above Earth’s orbit, and this image, showing it will be well ahead of the earth in it’s oribt and the videos below created by 2012hoax.org member obaeyens using the orbital simulator AstroGrav.
The Earth will not pass through Elenin’s tail.
A common misconception of comets is that the tail streams out behind the comet. Even if that were the case, the images and video above show that we would not pass through the tail. However, the tail of a comet does not stream out behind the comet’s path, but rather points away from the Sun. As such, the tail will never be in a position to cross the path of the Earth.
Even if the Earth were to pass through the tail of the comet, the only effect on the Earth would be a nice show of meteors. The Perseid meteor shower occurs every year between August 9 and 13 when the Earth passes through the orbit of Comet Swift-Tuttle. Comet Halley is the source of the Orionid shower in October.
Leonid Elenin is a real person.
Yes, it has been claimed that “Leonid Elenin” does not, in fact, exist, but that instead his name is a ‘coded message’. The poster finishes off a list of what they see as ‘hints’ in the circumstances with the statement:
You know the way TPTB operate. Everything is scripted well in advance and they use Hollywood to drop clues.
Or, it could be that the poster watches too many fictional movies and thinks that they are ‘coded messages’ from “The Powers That Be”.
Does Leonid Elenin even exist? http://www.abovetopsecret.com/forum/thread675535/pg1
Comet Elenin a “smokescreen” for Nibiru: http://humansarefree.com/2011/02/elenin-comet-smokescreen-for-nibiru.html
Don Yeomans on C/2010 X1
Don Yeomans has weighed in on the comet, saying:
“So you’ve got a modest-sized icy dirtball that is getting no closer than 35 million kilometers,” said Yeomans. “It will have an immeasurably miniscule influence on our planet. By comparison, my subcompact automobile exerts a greater influence on the ocean’s tides than comet Elenin ever will.”
NASA’s David Morrison on Comet Elenin claims
“The comet never comes close to the Earth, but it is expected to be visible in binoculars during August and October. Part of the Internet chatter concerns its size. Comets are exceedingly small and enveloped in a tenuous cloud of gas and dust, so the only way to be sure of their actual dimensions is to visit with a spacecraft. This means its mass is less than one billionth the mass of the Earth. Needless to say, we will not be aware of the tiny gravitational pull from Elenin.”
This is a quote from a David’s answer to a question on the “Ask an astrobiologist” page. He has received lots of questions about Elenin as well.
1. Elenin, Leonid. “Новый интересный объект нашей обсерватории | SpaceObs.” Сайт обсерватории ISON-NM / ISON-NM Observatory Site. Web. 06 Apr. 2011. <http://spaceobs.org/ru/2010/12/11/novyj-interesnyj-obekt-otkrytyj-nashej-observtaoriej/>.