More about Beecholme


Beecholme is also the first postwar "mixed development" housing scheme in Hackney, with a mixture of houses and flats with the taller block having five storeys and containing one-bedroom and bedsit accommodation. It is featured in Volume 15 of Hackney History and was the site of Beecholme House, the family home of Maj. John André (d. 1780), who was executed as a British spy in the American War of Independence.

Monday 27 December 2010

new planets found?

UPDATE: SEE COMMENT BELOW, thanks to "EDG"





Transit of new planet(s) around a dwarf star
or something else - like an eclipsing binary?


STAR 1

Here's a screen grab of the graph showing the transits I've already marked and numbered:


I dare say I will get confirmation in due course.
It might be a binary star or something else.


• • •

STAR 2

On my third hour I've just found what looks like another star binary system:

APH10025878

Here's a close up of one of the dip in light - notice the single missing reading at 17.7 days - apart from one or two instances, there is a missing reading every 3 days (approx) ie at 8.8, 11.8, 14.8, 17.8, 20.8, 23.8, 26.8, 29.8 and 32.8 - a coincidence or a planet?



and all of them numbered
As you can see, no 1, 3 & 5 look almost identical and are evenly spaced, as are 2, 4 & 6, with a period of only around 12 days?



• • •

STAR 3

After a break and only some 5 searches on I got this.
(app mag 14 at 1.3 sol)




close up



As and when I find out I'll let you know

• • • • • • • •




Here are some of the more usual graphs:











Why not try it yourself.
There are full instuctions (incl videos).



======================================


Comment from EDG

All three of the stars you're asking about are detached eclipsing binary systems - you can tell by the depth and shape of the dips.

A detached eclipsing binary is two stars orbiting eachother at a far enough distance that they're identifiable as two separate objects. If they're too close then one star's shape can get distorted (semi-detached binary) or they could even 'merge' into a peanut-shaped envelope containing both stars, which is an over-contact binary)

The first two are classic detached EBs, because you can see two dips with different depths. The reason you're seeing that is because one star is smaller and dimmer than the other, and as it passes in front of the brighter star it blocks off a certain amount of its light (the bigger dip).

As the stars continue in their orbit around their centre of mass, the brighter star will pass in front of the dimmer one from our point of view, but that won't reduce the total amount of light that we see as much (because the dimmer star is being blocked) - so that's the smaller dip.

So what you end up seeing is the the combined light of both stars (the flat part of the lightcurve, at a value of around 1.008), the big dip (the dimmer star passing in front of the brighter one) then the light from both stars again, and the small dip (the brighter star passing in front of the dimmer one) and then it repeats.

If the two dips are equally spaced then the stars' orbits are circular. If you can see distinct pairs of small dips and large dips, then the stars' orbit is eccentric.

The third system you show is less obviously a detached EB, but I'm pretty sure it is because the depth of the dips is pretty big (from 1.008 to 0.82) - dips that large means that a significant amount of light is being blocked off, implying (if it's a planet) that it's quite a big object - too big to be a planet, in fact.

I think the reason for the waviness of the 'flat' line is that you have two stars here that are not too different in brightness. I think the waviness is caused the brighter star coming towards us and the dimmer star going away from us between transits.

Hopefully that helps you make sense of it!

===========

Thank you "EDG"

Star no 2 (APH10025878) I noticed a missing reading every 3 days (single reading) and have added a note in red above. Seems a bit of a coincidence. Any ideas?



For those of you who do decide to start hunting for planets there is a lot of help out there, readily available.

I found this site useful, with examples of planetary transits: illustrations and explanations with links:

http://evildrganymede.net/tag/extrasolar-planets/






4 comments:

EDG said...

All three of the stars you're asking about are detached eclipsing binary systems - you can tell by the depth and shape of the dips.

A detached eclipsing binary is two stars orbiting eachother at a far enough distance that they're identifiable as two separate objects. If they're too close then one star's shape can get distorted (semi-detached binary) or they could even 'merge' into a peanut-shaped envelope containing both stars, which is an over-contact binary)

The first two are classic detached EBs, because you can see two dips with different depths. The reason you're seeing that is because one star is smaller and dimmer than the other, and as it passes in front of the brighter star it blocks off a certain amount of its light (the bigger dip).

As the stars continue in their orbit around their centre of mass, the brighter star will pass in front of the dimmer one from our point of view, but that won't reduce the total amount of light that we see as much (because the dimmer star is being blocked) - so that's the smaller dip.

So what you end up seeing is the the combined light of both stars (the flat part of the lightcurve, at a value of around 1.008), the big dip (the dimmer star passing in front of the brighter one) then the light from both stars again, and the small dip (the brighter star passing in front of the dimmer one) and then it repeats.

If the two dips are equally spaced then the stars' orbits are circular. If you can see distinct pairs of small dips and large dips, then the stars' orbit is eccentric.

The third system you show is less obviously a detached EB, but I'm pretty sure it is because the depth of the dips is pretty big (from 1.008 to 0.82) - dips that large means that a significant amount of light is being blocked off, implying (if it's a planet) that it's quite a big object - too big to be a planet, in fact.

I think the reason for the waviness of the 'flat' line is that you have two stars here that are not too different in brightness. I think the waviness is caused the brighter star coming towards us and the dimmer star going away from us between transits.

Hopefully that helps you make sense of it!

David White said...

Hi EDG, thank you.
I've since noticed a gap every 3 days, of a single reading for star 2 (APH10025878). I appreciate it could be an artifact, it's just the coincidence needs an explanation.
Any ideas?
David.

EDG said...

Not sure about the missing points... most likely it's a data artefact (maybe it's when data is sent back to Earth, or Kepler's doing some regular diagnostics?). Might be worth asking about it on the PH boards.

David White said...

Hi EDG,
Taken your advice - new discussion started at:
http://talk.planethunters.org/objects/APH10025878/discussions/DPH1003a6i