Exoplanets, or extra-solar planets, are planets which orbits stars other than our Sun. Exoplanets are discovered by several detection methods (see this NASA website for clear explanations and cool animations).
One of the exoplanet detection methods is called the Transit Method. When a planet passes in front of a star, it blocks some of the star-light. NASA's space telescope, the Kepler Mission, discovered several thousands of exoplanets using the transit method.
However, the transit method has three limitations:
- Geometrical Limitation: The transit method can only find those exoplanets, whose orbits are aligned from our point-of-view. Technically, the sky-projected inclination of an exoplanet's orbit needs to be close to 90°.
- Detection Biases: Physically, large planets closely orbitting a small quiet star produce a much stronger transit signal-to-noise ratio. This means that planets which are easy to find are found more often, while hard-to-find planets remain elusive.
- Completeness and Reliability: What if any other object, besides a planet, were to periodically transit a star? They may also generate a transit signal. These are called False Positives. We can try to understand these signals and try to get rid of them. But, what if we mis-identify a real exoplanet signal as a false positive? These are called False Negatives. Understanding both false positives and false negatives, allows us a better understanding of true positives and true negatives. This tells us how reliable and complete are the findings of any survey, in general.
Essentially, we want to have a deeper and better understanding of the cosmos and its intricate physical inter-connectedness. To this end, we need to compare our theoretical understanding of any physical phenomenon with nature via experiments or observations.
For Exoplanets: In order to understand how planets are formed, we can simulate the environment in which they are born, namely - protoplanetary disks (check out these deeply moving and fabulous images of protoplanetar disks from ALMA). Using theoretical and numerical calculations we can simulate and study the growth of several thousands of planets.
KOBE is a program which allows theoretically simulated planets to be compared with exoplanets found by the transit method. This allows us to study so-many things, statistically!
KOBE adds the geometrical limitations and the physical detection biases of the transit method (mentioned above) to a given populations of theoretical planets. In addition, it also adds the completeness and reliability of a transit survey.
KOBE has three modules for this: KOBE Shadows, KOBE Transits, and KOBE vetter. Each module takes care of each limitation mentioned above. To read more about the details, see my paper Mishra et. al. 2021.
Here are a few images of synthetic systems as their transit geometry is examined by KOBE. The colored bands shows the Transit Shadow Band for all planets in the system.
You can use KOBE for your studies!
If you want to compare a theoretical population of planets with exoplanets found by a transit survey, you can use KOBE to bias your theoretical population.
KOBE stands for Kepler Observes Bern Exoplanets. The name reflects its origin. The first project where KOBE was used had:
- Transit Survey - Kepler space telescope
- Theoretical planet formation model - Bern Model
The way I imagined it was: that somehow the telescope Kepler was pointing at Earth, in my computer, and looking at the planetary systems formed by the Bern Model. Literally, Kepler Observes Bern Exoplanets.
Yes! KOBE can be, in-principle used for other transit missions/surveys like: PLATO, TESS, etc.
List of publications utilizing KOBE:
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Mishra et al. 2021
Original publication introducing KOBE. Analyze and comparing the architecture of theoretical planetary systems formed by the Bern Model, with the exoplanetary systems found by Kepler. Read more about peas in a pod
For any more details or comments or suggesitons, you can contact me via my website.