With a perihelion distance
of 0.14 a.u., Phaethon comes closer to the Sun than any other named asteroid.
After perihelion distance
, you will see the separate nuclei gradually drifting apart.
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.
While 46P moved closer to Jupiter, the planet's gravity perturbed the comet's orbit, reducing both its perihelion distance
and orbital period.
A retrograde orbit with perihelion distance
of 0.026au was published on MPEC 2001-D07 [2001 Feb 18], though Marsden notes 'The above retrograde orbit solution seems more probable than a direct one.'
4), Peter Tyson refers to the newly discovered interstellar visitor 'Oumuamua as a "near-Earth object." This seems reasonable, as this asteroidal object's perihelion was 0.255 astronomical unit (on September 9, 2017), and the official definition of NEOs is "asteroids and comets with perihelion distance
q less than 1.3 au" (cneos.jpl.nasa.gov/ about/neo_groups.html).
The comet reached its present orbit after a very close encounter (0.05 au) with Jupiter in 1959, which reduced the perihelion distance
from 2.74 to 1.28 au.
Its perihelion distance
is so small that there are very few comparable objects on which to base predictions.
It appears to have been a relatively ordinary Apollo asteroid having a perihelion distance
of 0.8AU and aphelion of 2.5AU.
Since Comet 1973f has a perihelion distance
that is only about a quarter that of Comet Bennett, it should become much brighter; and if it develops a dust tail, it could be the most spectacular comet of the century.
One D/ [destroyed, or disappeared] comet has predictions for a return, though searches at favourable returns in the intervening period have failed to reveal the comet and its orbit has been perturbed by Jupiter to give a larger perihelion distance
. There is however always a chance that it will be rediscovered accidentally by one of the sky survey patrols.
Perhaps the closest analog is Sedna, whose perihelion distance
of 76 a.u.