Exoplanet HAT-P-9b
| RA | 07 20 40 |
| DEC | +37 08 26 |
| Out of transit V magnitude | 12.3 |
| Measured transit duration (mins) | 191.8 ± 4.6 |
| Measured transit depth (mmag) | 15.3 ± 1.1 |
HAT-9-b is a "hot jupiter" planet orbiting a star 480±60 parsecs away in the constellation Auriga. It was discovered in 2008 as part of the HATNet project. The planet has a radius of 1.4±0.06 times Jupiter and orbits it's parent star every 3.92 days. The star is a F type star of mass 1.28±0.13 solar masses.
This transit was observed on Christmas eve with the moon at ~90% and only 40° from the target. I used a Wratten 25A filter (aprox 600nm longpass) to cut down on sky background. Errors on data points are calculated to be ±6.3mmag. Standard deviation on out of transit data is 7.0mmag. Error bars have been omitted from the plot for clarity, however one bar has been added on first data point. Contributions from Poisson noise and scintillation appear to be approximately equal in this run of 60 sec exposures. In future I will be increasing the image scale in order in to increase the exposure time without going beyond the linear part of my CCD response. This should further reduce the main sources of noise.
The plot of the transit may be seen below. I submitted the data to the Exoplanet Transit Database.
A model fit to the data is made and compared with a 7 point running average in the plot below.
The data was analysed using the Exoplanet Transit Database modelling tool and the output can be found here: http://var2.astro.cz/EN/tresca/transit-detail.php?id=1293734706. Measured system parameters appear as below:
Finder chart and atmospheric/observing conditions below
