The current planet count stands at 490

[amalmirando]

The current planet count stands at 490 but can scientists gurantee 100% that they are planets. For instance, isn't it possible to identify a star passing in front of another star (binary) when looking at the light curve?

 

[zhermes]

A few of the large jupiter-like planets are big enough that they might be brown-dwarfs, but most of them are planets. From the light curves (or radial velocities) you can deduce some of the properties of the object and figure out what it is. Also, generally, there would be lots of particular characteristics that its just a binary star system.

 

[Nabeshin]

but can scientists gurantee 100%?

Scientists can't guarantee anything 100%.

 

[Astronuc]

The current planet count stands at 490 but can scientists gurantee 100% that they are planets. For instance, isn't it possible to identify a star passing in front of another star (binary) when looking at the light curve?

For a binary star system, there would be two minima in the light (magnitude) of the star - corresponding to passage of one star in front, and then again when the star passes behind the other. This assumes that the stars revolve such that the line of observation passes through them.

A planet-star system would have one minimum, assuming that the rotational plane is parallel (or nearly so) with the line of observation, i.e. that the planet passes between the star and observer.

One has to wonder how many planets are missed because we're looking perpendicular (or nearly so) to the plane of revolution.

 

[nickthrop101]

binary star systems havnt definative charectaristics. You could also look at if the star wobbles , then you could arguye that a gravitational force from a planet could be their.

 

[nickthrop101]

*have

 

[Borek]

One has to wonder how many planets are missed because we're looking perpendicular (or nearly so) to the plane of revolution.

Assuming angle between axes of rotation for planetary systems and galactic plane is completely random, it should be relatively easy to estimate number of those not seen just considering geometry of the systems involved. No idea if the assumption holds.

 

[amalmirando]

thanks a lot guys...

 

[DaveC426913]

Assuming angle between axes of rotation for planetary systems and galactic plane is completely random, it should be relatively easy to estimate number of those not seen just considering geometry of the systems involved. No idea if the assumption holds.

And it would be huge. The angle between our line of sight and the system's plane must be within a tiny fraction of a minute of a degree. Which means the transiting method is missing 99.99%+ of the planets. That's why we use many other methods.

Transiting misses a lot. But what it does catch is great, because it works on much smaller bodies than wobble and other methods.

 

[amalmirando]

It means there could be millions of planets still hiding from us ...

 

[Vanadium 50]

Of course there are. There are hundreds of billions of stars in the Milky Way Galaxy. Most of these stars have never even been catalog and many of them surely have planets.

 

[DaveC426913]

Of course there are. There are hundreds of billions of stars in the Milky Way Galaxy. Most of these stars have never even been catalog and many of them surely have planets.

That's not the point; the point is this:

We've spotted several hundred stars with planets locally.
And our techniques miss 90% of the stars with planets.
Which implies that there are hundreds more stars with planets right in our own neighbourhood.