Can tiny differences in luminescence lead us to discover alien planets? My research this week yields to answer this question contrary to the answer I expected. I thought that I would find a simple answer of yes, when the moon blocked our sun on August 21st, 2017 it got dark. So, that means that we can find exoplanets by observing the light patterns or luminescence given off by parent stars, right? While this scientific claim is in fact partially true it’s also wrong because this claim doesn’t tell us the whole story. Light observation alone cannot detect an exoplanet orbiting another star outside our solar system.
In a scientific review article by Drake Deming and Sara Seanger I found this bit of information. “The exoplanet, 51 Peg b was discovered by measuring the line-of-sight velocity of the star as it orbited the center-of-mass of the system.” In simpler terms the light detection alone did not lead to the discovery of 51 Peg b. This proves that the discovery of exoplanets has to be done by a combination of factors and mathematical calculations. What these two authors are claiming is that by using the Kepler law of planetary motion as a guide the calculations were able to prove the existence of 51 Peg b. However, they did need to observe the light being blocked from the parent sun of this planate first. This lead scientists to the theory that there was a planate there, but to prove it they had to calculate how much light was blocked in relation to the normal light being emitted from the parent star. From here they could calculate the mass, size and velocity of the star and the planate making a transit in front of the star.
I also found by reading in a second article published by Australian Geographic the same information that I had found in my first article about light only being able to detect the wobble and light radiation discrepancy of stars and not exoplanets. At least, not directly. The article from Australian Geographic brings up an interesting point. If light can be omitted by the exoplanet itself, it will become undetectable. This could also apply if the planate where to have a light reflecting surface such as our moon.
Third, only a small percentage of exoplanets can be detected at this time because only about thirty presents of our observable star systems have planets close enough to their suns for us to detect a light discrepancy. The first exoplanets to be discovered where known as Hot Jupiter’s, large gaseous planets that are extremely close to their stars also block out a significant amount of light compared to an earth sized planate.
Fourth, “The increasing accuracy of spectrometers makes it possible now to detect planets down to masses of a few Earth masses.” However, the problem with these methods is that only planets who are close to their stars are detectible at this present time. Originally, scientists went about looking for exoplanets by looking for a small wobble in the star’s orbital path. The gravitational effect of a planate on its parent star is that the small traces of gravitational attraction pulls the parent star in a small circular path towards the planets that orbit it. Because this method produced not very accurate results it was abandoned. The wobble of a star was hard to detect until recent technology improved detection ability’s. Now the wobble of a star is used as evidence leading to the prof of the presence of an exoplanet but just like light differences, it alone does not prove the presence of an exoplanet either.
Finally, to sum up, I have found that light pattern observation alone cannot discover an exoplanet. However, by building on the knowledge that an exoplanet can indeed block the light of its star we are able to mathematically calculate its presence.
Sources and References:
Article One: Deming, D., & Seager, S. (2009). Light and Shadow from Distant Worlds. Nature, 462(7271), 301-306. doi:10.1038/nature08556, Accessed on 9/29/17,URL: http://web.a.ebscohost.com.byui.idm.oclc.org/ehost/pdfviewer/pdfviewer?vid=7&sid=2e24db39-471c-4832-8838-2f1cfcab8c90@sessionmgr4009
Article Two: Watson, F., (n.d.) Planetary Stealth Mode, Australian Geographic, Accessed on 9/29/17 from URL:
Article Three: Ron, C., (7/5/2005) Space Research and Technology, Accessed on 9/29/17 from URL: <http://web.a.ebscohost.com.byui.idm.oclc.org/ehost/detail/detail?vid=15&sid=2e24db39-471c-4832-8838-2f1cfcab8c90%40sessionmgr4009&bdata=JnNpdGU9ZWhvc3QtbGl2ZQ%3d%3d#AN=33006345&db=aph
Article Four: Beust, H., Bonneau, D., Mourard, D., Lafrasse, S., Mella, G., Duvert, G., & Chelli, A. (2011). On the use of the Virtual Observatory to select calibrators for phase-referenced astrometry of exoplanet-host stars. Monthly Notices Of The Royal Astronomical Society, Accessed on 10/3/17 from URL: http://web.b.ebscohost.com.byui.idm.oclc.org/ehost/pdfviewer/pdfviewer?vid=6&sid=94b2e3c5-1db3-4eaf-a75f-a7ba5116605a%40sessionmgr120
Video One: Crash Course Astronomy Episode 27: Exoplanets
Phil, (August 6th, 2015) Crash Course Astronomy Episode 27: Exoplanets [Video File]. Accessed on 9/30/17 from URL: https://www.youtube.com/watch?v=7ATtD8x7vV0&t=184s
(The reason I have cited this video is that I used it to gain some background information of my topic, the information provided in this video was confirmed by my articles from reputable sources. However, it is a source of information, therefore cited to give credit to where credit is due.)