Tess Pre Observation Form Example: Fill & Download for Free

What is the reason that the Transit Method of detection of exoplanets suffers from a high rate of false detections?I think the academically approved answer is:“Many points of light in the sky have brightness variations that may appear as transiting planets by flux measurements. Difficulties with false detections in the transit photometry method arise in three common forms: blended eclipsing binary systems, grazing eclipsing binary systems, and transits by planet sized stars.” — Methods of detecting exoplanets - WikipediaAnd… if transit photometry were indeed a valid method of detecting Earth-zone exoplanets, I would add: natural magnitude flux in stars, interstellar medium, and Earth’s own atmospheric conditions; these things also, can sometimes affect the photometric intake of light.However, the problematic word is transit.Let me expound…This is what a transit looks like; below Venus transits the Sun back in 2004:Generally, a planetary transit will last several hours or more.However, transits even in our own solar system are fairly rare, with Mercury transiting about every seven years, and Venus doing a double set of transits (8 years apart) every 105 or 122 years.Now, think about that…Even with the Sun taking up more than half a degree in the sky, and two interior planets on the same orbital plane as Earth, these “guaranteed” transits are still rare.(The reason there must be a transit for the photometric measurement, is because at the distance of planets, stars act as extended light sources, that therefore will limit any occluding planetary shadows.)So, how rare is an exo-transit?According to NASA:“TESS, launched in April 2018 and expected to start operations summer 2018, will observe around 200,000 stars at a 2-minute cadence using selected postage stamps on the pre-selected targets, and will observe at least 2,000,000 stars at a 30 minute cadence in the fullframe images with enough photometric precision to detect planetary transit signals. From the postage stamps alone, simulations have shown that TESS is expected to find ~5000 transit signals, about 35% of which are expected to be real planets for a total yield of ~2000 planets. From the full frame images, the number of transit detections is expected to be an order of magnitude larger with more than ~50,000 candidates and assuming a similar fraction of planetary detections resulting in ~20,000 planets.” — exoplanets.nasa.gov…Two-million stars by the way, is just about every star there is at V~11 and brighter… meaning, that’s just about the whole Tycho-2 catalog, which is almost a complete listing of stars (all stars not more than c. 100,000 times dimmer than Sirius).So… I guess exo-transits happen “all the time” then?No, they do not.The odds for a planetary system to have their star and orbits aligned with Earth are slim…And that is just the orbital plane odds.The odds of measuring of an actual planetary exo-transit are even slimmer, and become astronomically smaller the further out the planet is.…To be fair, there are some really large red super giants stars, with a lot more surface area.For example, if we plug in the numbers for Betelgeuse (assuming Betelgeuse had outer planets not engulfed, and that we knew these hypothetical planets’ orbital plane was miraculously aligned with Earth)… then, we could expect a rather very long transit every few hundred years consistently across Betelgeuse, this based on the length of time our own outer planets take to orbit the Sun… Que buena suerte!Anyhow, I am not sure how academia missed all this. It is similar to claiming to measure the Aristarchus angle at half-moon as something other than 90 degrees based on a non-viable methodology — the lesser angle cannot possibly exist due to the fact that the Sun’s diameter is greater the Moon’s orbital diameter, and due to the nature of light from an extended light source… though, believe me, I have made my share of miscalculations.Alright, that’s all… I hope that was interesting to some.