Exoplanet XO-1b in CrB

Dear group,

Good weather and very good seeing are finally here and represent an opportunity to brush off a serious amount of rust accumulated during winter and spring due to inactivity thanks to clouds, clouds and more clouds.

I was somewhat apprehensive in pursuing XO-1b due to the rich presence of the twelve-day old moon. As was the case with other occasions involving rich lunar light, I used my Baader IR-Pass filter for the pursuit of this 180-min transit and the resulting light curve exceeded my expectations.

The exoplanet XO-1b is very similar to Jupiter with respect to its mass and radius. Similarly, the host star is also very similar to our sun with respect to its spectral type, mass and radius.

For the result based on five hours total time and which includes 60 minutes pre-ingress, 180 minutes for the transit itself as well as 65 minutes post-ingress, I kindly direct you to www.perseus.gr/Astro-Photometry-XO-1-20090604.htm and where the 17 mmag drop in the magnitude of the parent star (11.19 pre-ingress) is beautifully documented.

I would like to thank my two faithful assistants - my AP160 and AP1200 - whose efforts make all of this possible!

Anthony.

Excellent stuff Anthony

I notice your start time to be 19:55UT and ingress at 20:56UT - Athens being only one hour difference from UT suggests to me that twilight must still have been a threat when you started.

Remarkable.

For planetary transits to be detected requires the Earth, exo-planet and star to be incredibly close to the same plane.
So much so one would think that the probability of detection would be near impossible - and a number have now been detected.
Makes one think that there is a correlation in the planes of planetary orbits and the orbits of their stars around the galaxy.

Mark

Hi Michael,

One small correction: we are two hours ahead of Greenwich.

I had two full hours before the start of ingress and where I used the first hour to very thoroughly test the best combination of filter, exposure length and binning mode.

Surrounding your comment about optical alignment, of the 349 exoplanets detected so far, only 52 or so involve an actual transit as viewed from earth. The other exoplanets have been detected using radial shifts and I will look into this technique myself to see if I can do something similar so as to go after the remaining exoplanets.

The transit method is very useful since it allows for an immediate assessment of the exoplanet's size as well as orbital period.

Anthony.

Thats very serious stuff there Anthony, 1 down 51 to go!
I've never heard of any kind of corrolation between the galactic plane and star system ecliptics, I would imagine more local influences would be domimant during the systems formation like a passing/nearby star.

Dave_Lillis wrote:

Thats very serious stuff there Anthony, 1 down 51 to go!

Excuse me?

We have nineteen captures so far and counting: www.perseus.gr/Astro-Photometry.htm ... with two complete scopes up and running, I sincerely hope to knock all of them off this year.

I have been successful in capturing an exoplanet transit as low as 6 mmag and my next target is an exoplanet in Cassiopeia whose transit depth is 5 mmag. If I can be successful with this one at 5 mmag, we have targets at transit depths of 3 mmag.

My standard errors with these measurements have been as low as 3 mmag which does give me some hope in going below my best capture so far at 6 mmag. However, things are getting very tight at these levels.

We also have a handful of exoplanets whose parent star is mag 16 and higher which is another area and source of experimentation for me since what drives success with this work is a very good S/N ratio and things get ugly at mag 16 and dimmer.

I have a new beast coming (AP 305/f12.5 Mak-Cas) which will help in getting even better S/M owing to the much greater aperture.

I've never heard of any kind of corrolation between the galactic plane and star system ecliptics, I would imagine more local influences would be domimant during the systems formation like a passing/nearby star.

Well, I am certain the Kepler mission will change this area of astronomy dramatically over the next few months since it will be covering a specific area of the sky for such transits and especially involving earth-like planets.

Anthony.

PS. I forgot to mention that a new weapon in my arsenal right now is my ST-10XME which allows me much greater depth (well depth of 77,000 e-) and it is very sensitive as well as NABG. This is contrast to my earlier work involving my ST-2000XM which has lower sensitivity, a lower well-depth (45,000 e-) and which is linear only for the first 22,500 ADU, this seriously limiting my efforts.