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alfa015

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About alfa015

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    Astronomy

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  1. As some of you might know, I have designed a crewed interstellar spacecraft that I call Solar One. Basically, large flexible mirrors placed near the Sun would propel a one-mile light sail with a 4–crew spacecraft of 300 tons. To decelerate, an on-board compact fusion reactor would power a photon rocket placed at the front of the spacecraft that would 1) help decelerate and 2) ionize space hydrogen for the nuclear reactor. A Bussard scoop also placed at the front of the spacecraft would 1) collect those protons (ionized hydrogen) and 2) decelerate the spacecraft. Solar One would achieve an average of 22% the speed of light, which would allow the crew to reach the closest potentially habitable exoplanet in less than 19 years. Of course cryo-sleep and artificial gravity must be achieved first. Here is my paper in arXiv: https://arxiv.org/abs/2007.11474 And here a short movie of Solar One: URL deleted Feedback is appreciated!
  2. We report the discovery of a new exoplanet candidate orbiting the star GJ 3470. A total of three transits were detected by OKSky Observatory: the first one on December 23, 2019, the second one on February 27, 2020, and the third one on May 3, 2020. We estimate an average transit depth of 0.84 percent and duration of 1 hour and 2 minutes. Based on this parameter, we calculate a radius of 9.2 Earth radii, which would correspond to the size of a Saturn-like exoplanet. We also estimate an orbital period of 66 days that places the exoplanet inside the habitable zone, near the orbital distance at Earths equivalent radiation. Another twelve potential transits that do not belong to GJ 3470 b are also reported. Despite our candidate for GJ 3470 c still has to be confirmed by the scientific community, the discovery represents a turning point in exoplanet research for being the first candidate discovered through an international project managed by amateur astronomers.ç Sources: https://arxiv.org/abs/2007.07373 http://exoplanet.eu/catalog/gj_3470_b/ https://www.youtube.com/channel/UCdDS4j318UpKjNcpe_LeQxQ/community
  3. Hi everybody, I would like to share with you a crewed interstellar spacecraft which I have designed and called Solar One. It employs a combination of 3 propulsion methods: nuclear fusion, beam-powered propulsion , and photon propulsion. Basically, several compact fusion reactors power a laser system that propels a huge light sail. Physicist Robert Forward already proposed in 1983 to use a 26-TW laser system to propel a 100-km light sail, a fresnel lens to focus the beam of the laser, and decelerate the spacecraft with a secondary light sail. I propose something a bit different, which is to use to use for example a 60 TW-laser to propel a 5-km light sail that would deploy from the spacecraft after the acceleration stage, use parabolic mirrors that gradually change their orientation in order to focus the laser beam, and finally use a photon rocket to decelerate the spacecraft. In theory, it could be possible to achieve 25% the speed of light, reaching the closest potentially habitable exoplanet in less than 20 years. There are of course many challenges, like building high-energy continuous-wave lasers, reducing the weight of the nuclear fusion reactors (and of course achieving effective nuclear fusion first), and minimizing the effects of zero gravity during such a long trip. What do you guys suggest to overcome these challenges? You can find a short video that summarizes all in youtube by searching for The Exoplanets Channel.
  4. Hello, I would like to share with you the info we have so far about habitable exomoons: 1. We have detected 9 exomoon candidates, but none of them are potentially habitable. 2. A habitable exomoon would have a mass between 0.25 and 2 Earth masses. 3. The mass of the host planet has to be at least 3 times the mass of Jupiter, and it should not be tidally locked to the star. 4. A study has identified more than 70 gas giant exoplanets that could host habitable exomoons, but all of them are located far away. 5. Within 100 light years, there could be around 33 habitable exomoons orbiting Sun-like stars, 109 around K-type stars, and 121 in red dwarf star systems. More info about habitable exomoons SPAM LINK DELETED Do you think exomoons could be more habitable than exoplanets?
  5. Guys, I made a short video that some of you might find helpful, especially these times At least it was helpful for me while I was making it. Just some cinema shots with some music; I just put them together. Here it is: video link removed
  6. Book ''Is there life out there?'', by Sara Seager: https://www.saraseager.com/wp-content/uploads/2016/08/book-is-there-life-out-there.pdf SPAM DELETED Search for exoplanets online: https://www.zooniverse.org/projects/nora-dot-eisner/planet-hunters-tess/classify AND https://www.zooniverse.org/projects/ianc2/exoplanet-explorers/classify NASA app Eyes on Exoplanets: https://exoplanets.nasa.gov/eyes-on-exoplanets/#/
  7. Hi, I would like to share with you guys a couple of interesting simulations. This simulation belongs to an Earth-like planet located 4 light-years away, imaged with the European Extremely Large Telescope (ELT), expected in 2025: This other simulation belongs to an Earth-like planet located 40 light-years away, imaged with the Large Ultraviolet Optical Infrared Surveyor (LUVOIR), expected in 2035: SPAM DELETED What is the first exoplanet you would like to see an image of?
  8. Here some mind-blowing possibilities about super habitable exoplanets: 1. The colour of the sky could be light blue, similar to the colour of the sky on Earth in summer. 2. The oceans could be shallow, with a turquoise blue colour. 3. The vegetation could cover more regions than in Earth, and the colour of the trees could be purple. Do you agree with these hypotheses?
  9. I would like to talk about an instrument that has been sometimes overlooked: ESPRESSO. As most of you probably know, ESPRESSO is the only current spectrograph able to detect Earth-sized planets. I think it will be a key instrument for 2 reasons: 1- The majority of the most potentially habitable exoplanets were discovered with the radial velocity method. 2- Only 0.5 % of the Earth-like planets in the Milky Way could be detectable by using transit photometry. Do you think we will find a nearby Earth 2.0 with ESPRESSO in 2020?
  10. I think that Alpha centauri could host the closest Earth-like planet. A study shows that 22% of G and K-type stars could have Earth-like planets orbiting in the habitable zone. There are 9 Sun-like stars within 25 light-years. If we make the calculation, two of those stars could have an Earth-like planet. One of those two exoplanets could be Tau Ceti e. Which exoplanet could be the other one? 7 out of the 9 closest Sun-like stars have low metallicity. The only two stars with high metallicity are Alpha Centauri A and Delta Pavonis, but this star is suspected to be variable. What do you guys think?
  11. Hi, Forbes just published an article about the Habitable Exoplanet Hunting Project: http://www.forbes.com/sites/jamiecartereurope/2019/11/25/inside-the-247-search-for-another-habitable-planet-within-100-light-years-of-earth/#149fbf103442 I hope you find it interesting! We welcome any type of observatory to join us. Cheers!
  12. As some of you probably know, the Square Kilometre Array will become the biggest radio telescope on Earth, with a collecting area of 1 square kilometre. The construction will start in 2021 and the first light is expected to take place in 2027. It will cover the frequencies from 50 MHz to 15 Ghz. But what I wanted to share with you guys is a new study about how far the SKA can 'listen'. A recent study points out that the SKA could detect extraterrestrial airport radars 200 light years away. SPAM DELETED What do you guys think?
  13. In October 2012, astronomers announced the discovery of an exoplanet orbiting the star Alpha Centauri B. However, three years later, they concluded that it probably doesn’t exist. In 2013, astronomers also detected another possible exoplanet, but it hasn’t been confirmed yet. As of today, no exoplanets have been discovered around Alpha Centauri A or B. There are several ongoing projects to search for habitable exoplanets in Alpha Centauri: The Expresso spectrograph, which started operating in October 2018, is able to detect radial velocities of less than 10 cm/s. Another promising instrument is called NEAR, which stands for Near Earths in the AlphaCen Region. NEAR is a thermal infrared coronagraph that blocks most of the light coming from Alpha Centauri in order to resolve possible exoplanets around the star. This coronagraph can detect exoplanets 2 times the radius of the Earth. Project Blue is another interesting project that might help us discover the closest Earth-like planet. It is a small space telescope with a coronagraph that will directly image the habitable zones of the Alpha Centauri system. The telescope will be able to detect exoplanets between 0.5 and 1.5 times the radius of the Earth. The launch of the telescope is expected to take place in 2023. NASA is also working on a space telescope with coronagraph called ACEND, which stands for Alpha Centauri Direct Imager. Breakthrough Initiatives is now working on a space telescope called TOLIBOY that will use astrometry to map the motion of the Alpha Centauri stars and search for a perturbation in the positions. The telescope is expected to be launched in 2021. SPAM DELETED Do you think all the agencies and companies should join efforts and build just 1 big space coronagraph, or, as they seem to be doing now, work on different ones?
  14. The massive planet, which shouldn't exist based on current theories, is prompting astronomers to revisit their models for planetary formation. Source: https://astronomy.com/news/2019/09/giant-planet-found-around-tiny-star-defies-expectations
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