[However Schleicher, a planetary astronomer at the Lowell Observatory has come up with three intriguing scenarios to explain origins of Machholz 1, and each one will yield important but differing new constraints on the formation or evolution of comets.

One possible explanation is that Machholz 1 did not originate in our Solar System, but instead escaped from another star. In this scenario, the other star's proto-planetary disk might have had a lower abundance of carbon, resulting in all carbon-bearing compounds having lower abundances. “A large fraction of comets in our own Solar System have escaped into interstellar space, so we expect that many comets formed around other stars would also have escaped,” said Schleicher. “Some of these will have crossed paths with the sun, and Machholz 1 could be an interstellar interloper.”

Another possible explanation for Machholz 1's anomalous composition is that it formed even further from the sun in a colder or more extreme environment than any other comet we have studied thus far. If this was the case, then the scarcity of such objects is likely associated with the significant difficulty of explaining how such comets moved into the inner solar system where they can then be discovered and observed.

A third possibility is that Machholz 1 originated as a carbon-chain depleted comet but that its chemistry was subsequently altered by extreme heat. While no other comet has exhibited changes in chemistry due to subsequent heating by the sun, Machholz 1 has the distinction of having an orbit that now takes it to well inside Mercury's orbit every five years. (Other comets get even closer to the sun, but not as often). “Since its orbit is unusual, we must be suspicious that repeated high temperature cooking might be the cause for its unusual composition,” said Schleicher. “However, the only other comet to show depletion in the abundance of CN did not reach such high temperatures. This implies that CN depletion does not require the chemical reactions associated with extreme heat.” ]

I know and even in that cool realm:

[Currently there are two types of comets, these being identified by a program at the Lowell Obervatory in the early 1990s. One class, containing the majority of observed comets, has a composition called “typical.” Most members of this typical class have long resided in the Oort Cloud at the very fringes of our Solar System but are believed to have originally formed amidst the giant planets, particularly between Saturn, Uranus, and Neptune. Other members of this compositional class arrived from the Kuiper Belt, located just beyond Neptune.]

[Although the location of origin cannot be definitively determined for any single comet, Machholz 1's short orbital period means that astronomers can search for additional carbon-bearing molecular species during future apparitions. “If additional carbon-bearing species are also strongly depleted, then the case for its origin outside of our Solar System would be strengthened,” said Schleicher. The next opportunity for observations will be in 2012.]

Yep, from: Universe Today

I know! Sorry, I'm a believer of an Oort Cloud existance (and now even beyond one).

Amazing what goes on or even went on during our solar system's formation.