Category: Kumai A.
This week is my final week at the internship, and I already finished my presentation, so I haven’t really had anything to work on. I decided to do some research for myself, like about specific stars and telescopes. I did more research on the James Webb space telescope since it’s so close to release. I wanted to understand it’s workings a lot more. I also spent some time messing around with the program and this cool program that NASA has called “NASA’S EYES” which shows you the galaxy.
This has been a fun experience and I wanted to thank the whole team here at the Steward Observatory for making it memorable.
As many of you know I did my project with two other students and each of us worked on something a little bit different, but I wanna explain a little bit about the overall goal of the project as a whole. The goal of our project was to assess where habitable planets could be around stars within 10 parsecs and prioritize, determine which stars are already known to harbor planets, and create a target list for a future telescope biosignature survey. Our program looked a bit like this:
The results of the program look a bit like this:
The image above shows the habitable zone, in blue, around the star, the dot, and where the earth would be orbiting that star. The earth is meant to give an idea of where another planet with a similar characteristics could be and whether it would be around that stars habitable zone.
The image above shows another star and its habitable zone but in this image the earth is inside the habitable zone. Overall, the point of this is to show where astronomers should search for habitable planets.
As I was coming to the end of my project I had to begin working on my presentation. I needed to find a way to convey my research to an audience that didn’t necessarily know much about astronomy. In order to do that I had to go through my project step by step and see where it was important for my audience to understand a term or method. Luckily, I had done a pretty good job of defining lots of important terms throughout my blog posts but I realized that I never really mentioned what stellar type meant which is why I’m going to do that now.
Stellar type is used to classify stars based off of what elements that star absorbs and what its temperature is. The main one’s to know include O, B, A, F, G, K, M. It goes from O being the coolest to M being the hottest. Our sun is actually a G type star meaning it’s temperature falls between 5300-6000 Kelvin. Also our sun converts element hydrogen to helium in its core. It’s important to know what stellar type a star is to understand where its habitable zone will likely be.
AU – astronomical unit, distance from earth to sun, 92.96 million miles
This week wasn’t really busy since Andrei was working at his new job and Brendan was gone for a good portion of the week. Also we’re almost done with the project so there hasn’t been much to work on. This week at the Steward observatory there was a symposium taking place Monday and Tuesday, and on Thursday there was a joint colloquium series for Jay Farihi. His presentation was titled Exoplanetary Archaeology: Observing the Fossil Record of Rocky Planetary Systems. It was on the ‘archaeological’ method that would provide empirical data on the assembly and chemistry of exo-terrestrial planets that is unavailable for any planetary system orbiting a main−sequence star. I haven’t done any major new research but I’ve been focusing on learning future methods that’ll allow astronomers to characterize exoplanets atmosphere and other properties. Today we had a small meeting to discuss the usual Friday topics but many were unable to attend because they were working on their proposals for telescope time. Overall, this week was a little laid back when it came to my research due to all the presentations that happened.
I wanted to use this blog post to clarify and distinguish my project from that of Brendan and Andrei. As many know, the three of us are working at the same internship with the same overall goal but each of us have a different approach or part of the project. The overall goal of our project is to assess where habitable planets could be around stars within 10 parsecs and prioritize, determine which stars are already known to harbor planets, and create a target list for a future telescope biosignature survey. The project was split into three sub-projects that complement each other to create a final product. Brendan is the theoretical astronomer, Andrei is the observational astronomer, and I’m the instrument scientist. I focus on, as many could extrapolate from my posts, the actual telescopes and their capabilities.
Brendan and Andrei do most of the actual programming since they are far better than me, seeing as how both took computer science while I did not. The target list were working on includes stars and exoplanets that were discovered using many different ground based and space telescopes that I’ve been researching, but 10 parsecs is not that big a range it’s only 1.88 x 10^14 miles, so as telescopes advance the farther astronomers can look for habitable planets. My research is what helps define the limits for our target list and the exoplanets and stars on that list. Monday/ Tuesday I’m gonna post a bit more on some of the limitations that current telescopes have and how far they can really see.
Week 5 I shifted focus towards upcoming space telescope projects. Not only has there been lots of advancements in ground based telescopes but space telescopes as well. Many new and upcoming space telescopes will be able to see far into the depth of the galaxy. One of those upcoming space telescopes is the James Webb space telescope scheduled to launch in October 2018. The James Webb space telescope will provide unprecedented resolution and sensitivity. This telescope will allow for a broad range of research in astronomy and cosmology. The telescope should be able to see some of the most distant events and objects in the Universe, such as the formation of the first galaxies. This is far beyond the capability of any current ground and space based telescopes. It will also be used to study the formation of stars and planets capable of using direct imaging of exoplanets. Unlike other telescopes it will have a greater capacity to perform infrared astronomy which will help accomplish it’s goals better than visible light or ultraviolet astronomy. The astronomical scientists are very excited for the launch of this telescope.
Astronomers have always known that the Hubble space telescope won’t last forever but it sure has lasted longer than expected. If launched the Advanced Technology Large-Aperture Space Telescope (ATLAST) will replace the HST. ATLAST will have the ability to obtain spectroscopic and imaging observations of astronomical objects in the ultraviolet, optical, and infrared wavelengths, but with substantially better resolution than either HST or the James Webb Space Telescope. ATLAST is a planned mission for the 2025-2035 period with the major focus to determine whether there is life elsewhere in the galaxy, many refer to it as the “life-finder.” It will search for biosignatures, molecular oxygen, ozone, water, and methane, on exoplanets. The backronym, ATLAST, is actually a pun referring to how long it took to decide on a true, visible-light, successor for the Hubble Space Telescope, but it’s name will probably change as the project progresses.
Week 4 I focused my research on new projects and advancements for ground based telescopes. Scientists have been making progress when it comes to the image quality of ground based telescopes. One of those upcoming projects is the Thirty Meter Telescope, it was originally planned to be released in 2022 at the Mauna Kea Observatory in Hawaii. The centerpiece of the telescope is to be a Ritchey-Chretien telescope with a 30-metre (98 ft) diameter primary mirror, given by the name. If the telescope were to work as planned it should be able to get an image quality almost ten times better than the Hubble Space telescope. Unfortunately we’ll have to wait a bit longer for the release of this telescope because there have been lots of protest against the production of this telescope because Mauna Kea is the most sacred mountain in Hawaiian culture. The Supreme Court of Hawaii invalidated the TMT’s building permits so the TMT company has begun to look for other places where they could launch this telescope.
There are two more major upcoming ground based telescopes, the Giant Magellan telescope and the European Extremely Large telescope. The Giant Magellan telescope will be constructed in the Las Campanas Observatory in Chile. Commissioning of the telescope is scheduled to begin in 2022 and finish in 2025. The GMT has a unique design that’ll offer several advantages giving it a resolution power ten times greater than the Hubble Space telescope. How the GMT will work: Light from the edge of the universe will first reflect off of the seven primary mirrors, then reflect again off of the seven smaller secondary mirrors, and finally, down through the center primary mirror to the advanced CCD (charge coupled device) imaging cameras. There, the concentrated light will be measured to determine how far away objects are and what they are made of. The telescope will be located on one of the highest and driest locations on earth, Chile’s Atacama Desert, the GMT will have spectacular conditions for more than 300 nights a year. Las Campanas Peak (“Cerro Las Campanas”) has an altitude of over 2,550 meters or approximately 8,500 feet which is where the telescope will be located. The combination of seeing, number of clear nights, altitude, weather and vegetation make Las Campanas Peak an ideal location for the GMT, but the GMT is not the only telescope planned to be located in Chile.
The European Extremely Large telescope is now under construction in Chile. The Telescope will vastly advance astrophysical knowledge, allowing detailed studies of subjects including planets around other stars, the first objects in the Universe, super-massive black holes, and the nature and distribution of the dark matter and dark energy which dominate the Universe. The E-ELT will have an aperture diameter of 39.3 meters which is 9.3 meters bigger than the TMT, this will allow it to get images 15 times sharper than the Hubble space telescope. It is planned to see it’s first light in 2024.
Week 3 was just me and Brendan since Andrei was gone for the first four days due to some summer internship. This week I focused on learning the major differences between space and ground based telescopes. The majority of my research focused on the major differences, but how with future projects NASA is working on improving major downsides to both space and ground based telescopes. Next week I’m working on researching some of those new projects and their advancements. I addressed this a little in my last post but one of the major advantages of ground based telescopes is that they are a lot cheaper. Ground-based telescopes cost about 10 to 20 times less than a comparable space telescope. The costliness of a space telescope such as the Hubble telescope includes the cost of materials, labor and launching it into space. [Picture of hubble]
Telescopes on Earth cost less because they don’t need to be launched into space, and the materials used in creating a ground based telescope are not as expensive. The two ground-based Gemini telescopes each cost about $100 million whereas the Hubble telescope cost U.S. taxpayers approximately $2 billion. [gemini telescopes]
Another big issue is maintenance of the telescope. Despite the quality of the workmanship, all telescopes will require some sort of maintenance. Engineers on Earth can easily maintain and fix malfunctions in ground based telescopes, whereas a team of astronauts and a costly space mission would have to be assembled for any failures in space telescopes. Ground-based telescopes have longer lifetimes because they can be repaired relatively easily.
On Earth, image quality of telescopes is worse than those in space. The elements and particles in the Earth’s atmosphere bend light so that images detected from ground based telescopes appear blurry. The atmosphere causes the apparent twinkling effect of stars, although stars don’t actually twinkle in space. Even with the invention of adaptive optics, a technique that reduces the effect of atmospheric interference on image quality, it still can’t reproduce the image clarity of space telescopes. Images taken by space telescopes like Hubble produce clearer images. [picture contrasting image clarity]
There are a few more major advantages/disadvantages of ground based telescopes but they revolve around similar ideas to those I explained. The week came to an end with the weekly Friday meeting which was extra special because one of the co-authors, Adam Burgasser, of the paper on the seven temperate terrestrial planets around the nearby ultracool dwarf star TRAPPIST-1 gave a short presentation on his paper. Unfortunately I didn’t get a picture with him but his paper discussed the news that NASA came out with on February 22nd. Also the day before the meeting there was a colloquium on exoplanets by Dr. Ruslan Belikov from the NASA Ames Research Center titled Beyond Kepler: Direct Imaging of Exoplanets. It was a great presentation and very useful because I had been doing some research on Direct Imaging and this helped expand my understanding of it.
After the first week, I had begun to get into the flow of things. Since Brendan was gone for the first three days of week 2, Andrei and I were the only ones working on the project. Last week I focused on learning the different methods that astronomers use to detect exoplanets. This week I focused my attention on the telescopes that the astronomers use in order to detect exoplanets. Since there are lots of telescopes I needed to make my search more specific, so I decided to focus on the biggest ground based telescopes on earth currently in use. I did some research and found out that the biggest ground based telescope is the the Gran Telescopio Canarias followed by the Keck I and II, but I realized that I needed to know what the difference between ground based and space based telescopes is.
Space based telescopes are better than ground based telescopes because ground based telescopes are affected from image blurring. All images observed with ground based telescopes are affected by the image blurring that occurs as the light travels the last tiny fraction of its journey from the galaxies through the atmosphere of the Earth. The properties of the atmosphere cause photons to randomly and slightly change their direction, making the images appear fuzzy. Many might be wondering why astronomers continue to make ground based telescopes rather then just have more space based telescopes. The main reason is the cost difference: space based telescopes are extremely expensive compared to ground based telescopes. Also in the near future, ground based telescopes should be more advanced and capable of taking good images compared with those of space based telescopes images. Week 3 recap should dive into the differences between the two types of telescopes and their respective advantages and disadvantages, including examples with pictures.
Week 2 came to an end like the week before with our Friday meeting where we discussed some of the latest news in the science world. One cool news piece was that NASA is crowdsourcing people from the general public to find planet 9. After we discussed the news we dived into some interesting articles that some members wanted to share with the rest of us. Next week’s meeting should be really interesting because NASA had a big announcement planned for February 22nd and I can’t wait to discuss it. Brendan joined me and Andrei for the last two days of the week and on Friday the three of us had a check-up with our adviser where we could ask her questions and she’d see how well we were doing. I’m happy to say that it went well.
The first week of work was a lot of research on the internet, trying to learn a little planetary terminology. While Brendan and Andrei began to work on the basis for the program to calculate the habitable zone around a star, I focused on learning the different methods that astronomers use to detect exoplanets especially, the transit method and direct imaging of exoplanets. The transit method aka photometry has discovered the most planets as of this point, 2703. While direct imaging is a newer way and much harder to use has only discovered 44 planets. The reason direct imaging is difficult is because astronomers are trying to look at the light that a planet emits which is far dimmer than the host star, making looking for the planet difficult. It requires specific and advanced technology in order to try and block out the star’s light. The transit method is much simpler because it measures the minute dimming of a star as an orbiting planet passes between it and the Earth, kind of like a solar eclipse.
The week was brought to an end by the weekly friday meeting where we discuss some of the recent discoveries and after we go over the science news everyone has an opportunity to give a short presentation on a article they found interesting. After the meetings everyone goes back to what they were doing.