We have recently looked at planetary systems and questioned how they might form. We have seen that
the standard model of accretion does not hold up for many of these systems. So when astronomers
came across this star system which contained one very small star and one giant planet at an extreme
distance it asked more questions than they were able to answer. Let's explore this strange system.
About 450 light years from Earth Astronomers have found one of the strangest star systems ever.
Most binary systems consist of one main star and a companion.
This system appears to be a brown dwarf with another planet orbiting it.
The brown dwarf sits in the lowest end of possible brown dwarf sizes.
The system has the rather catchy name
CFHTWIR-Oph 98. It was discovered a few year ago using ground based observatories
and is located in a region of the galaxy where stars are known to be forming.
It was first observed in 2006 and later in 2012. It was classified as a brown dwarf. These are
objects that are thought to be more massive than a planet but smaller than a typical star. They do
not emit much light. In the electric star model these would be considered under powered stars.
In 2013 astronomers went back to observe the system using the Hubble telescope
and more recently in 2020 using the UKs Infrared Telescope.
When all of these images are compared a clear companion can be seen next to the star.
This made them immediately think that this star must have a companion star.
By examining the images over many years they were able to determine
that the companion was not a background star as it was moving with the star.
This presented another problem. At the distance the star was their clear separation meant these
two bodies were at least 200AU apart. That is over 6 times the distance from Neptune to the Sun.
Using the observations they attempted to get a mass estimate of the two objects
and this raised even more questions. The brown dwarf appeared to have the mass
of 15 Jupiters, this is the lower end of the scale for brown dwarfs. In the standard
model this means they would not be able to fuse deuterium for very long before ‘burning out’.
The companion seemed to have the mass of about 8 Jupiters,
well below Brown Dwarfs so confirming it was likely a planet.
It is important to point out that these mass determinations are highly speculative and based
on what they think the age of these objects might be, not on the dynamics of a moving system. When
we examine other star systems we are able to use a variety of techniques to determine the mass,
because the companions are passing in front of the star and causing the star to wobble.
This is not possible in this system and they only use the luminosity and the fact that they
can place this object as part of a group where new stars are known to be forming.
So based on the data the astronomers think this system is very new about 3 millions years.
The problem this presents is that this is a very low mass system. There is almost
not enough gravity in their model to hold the companion in orbit
and it really wouldn’t take much to pull the planet away from the star.
This in turn raises the question about how such a system could be formed in the first place. In
the standard model Brown Dwarfs form in the same way as stars. A dense cloud collapses creating a
disk surrounding the star at the centre. Planets are formed from the disk surrounding the star.
So here we come across another problem as the gas cloud that would form into a brown
dwarf would not contain enough material to form a planet 8 times the mass of Jupiter.
The second problem is that this disk would not place the planet as far out as it is.
This leaves them with the only option that both formed from direct collapse. But wait there
is a problem here too. In most binary systems that are thought to form from direct collapse
both will tend to end up with a similar mass but here we have one with twice the mass.
This system presents a real problem for the mainstream model of the formation through the
accretion process. In the electric universe brown dwarfs are simply underpowered stars.
Possibly sitting on the outer edge of a filament where the current density is lower.
It is also likely the so-called companion is not a companion at all but simply another star
located nearby on the same filament, possibly a little further back. The motion of this
star also tracks with other objects which are thought to be part of the same group.
Most notably one other member of this group is Rasalhague who some of you will remember from
when we looked at our motion around Arcturus and we saw that its proper motion indicated
that it was moving around the filament which Arcturus is part of. At this stage we do not
know if this star is also part of this filament or lies on a different filament. Further analysis
of the motion of other stars in the vicinity will need to be conducted to help determine this.