Sedna was discovered in 2003 by Caltech astronomer Mike Brown and his group, and was one of a series of possible dwarf worlds (together with similar-sized bodies like Haumea, Makemake, and Eris) whose discovery caused the demotion of Pluto in 2006. As best we can tell from a range, Sedna has to do with the very same size as Ceres, the largest object in the asteroid belt, but its composition and origins are really various. Its chemical makeup recommends it might be covered in deep reddish organic substances called tholins, the very same material seen on Pluto and other Kuiper belt items. Unlike Pluto, it is normally too cold for the methane abundant on its surface area to vaporize and fall back as snow, though Sedna might quickly acquire an atmosphere of nitrogen as it approaches the Sun.
What truly sets Sedna apart from the other known dwarf planet candidates is its huge orbit, which takes it out towards the inner edge of the Oort cloud, the most distant region of the Solar System, where long-period comets prowl. There are several contending theories to explain how Sedna ended up in this position. Perhaps the most high-profile theory is the possibility that a yet unidentified ninth planet, perhaps ten times the size of Earth, interfered with Sednas orbit and swept it and a number of other things out into extremely lengthened orbits. Visiting Sedna most likely will not solve this particular mystery, but it will tell us a lot about the structure of these extreme trans-Neptunian objects.
The orbit of dwarf world prospect 90377 Sedna (red) compared to Jupiter (orange), Saturn (yellow), Uranus (green), Neptune (blue), and Pluto (purple). Credit: Szczureq/kheider/NASA (Wikimedia Commons).
Reaching Sedna with a spacecraft wont be a basic job. Even at its closest technique, Sedna will just come about 76AU from the Sun.
In planning an objective to Sedna, the Voyager spacecraft are okay locations to try to find inspiration. They famously made the most of a lucky positioning of planets to take a grand tour of the outer Solar System, taking energy from Jupiter to gain ground and reach their more far-off targets. Similar gravity helps will be required to make the journey to Sedna workable. A team of scientists led by Vladislav Zubko from the Space Research Institute of the Russian Academy of Sciences recently modeled a series of possible trajectories to Sedna, preferring a 2029 launch date as the most possible option.
The 2029 trajectory, they identified, would take the spacecraft to Venus first, then back to Earth (two times), prior to passing Jupiter en route to Sedna, with flight times as short as 20 years but more optimally in the 30-year range. The longer flight time would increase the altitude of the spacecraft over Jupiter during the gravity assist, decreasing the time spent exposed to the gas giants damaging radiation.
A 30-year flight plan would also indicate passing by Sedna more slowly, supplying more time to collect information on the item. Picking this alternative would provide the spacecraft a relative velocity of 13.70 km/s as it passed Sedna, comparable to the speed at which New Horizons approached Pluto in 2015.
90377 Sedna as seen by the Hubble Space Telescope in 2004. Credit: NASA.
As a perk, this trajectory would also take the spacecraft past a 145km diameter asteroid named Massalia, supplying the team with an additional scientific target to study, in addition to a possibility to test the spacecrafts systems.
A 2nd trajectory proposed by the group would consist of a 2034 launch, and would offer a comparable extra flyby, this time of the metal asteroid 16 Psyche.
At the moment, its unclear whether an objective to Sedna will actually make it to the launch pad with all the contending choices available to mission coordinators in the coming decade, but as its our only opportunity in the next 11,000 years, the idea makes certain to be offered due diligence.
Zubko et al.s paper is available in pre-print format on ArXiv at https://arxiv.org/abs/2112.13017.
Included Image: Artists Rendering of Sedna. Credit: NASA/JPL-Caltech/R. Hurt (SSC-Caltech).
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Object 90377 Sedna– a far-off trans-Neptunian item known best for its extremely elliptical, 11,390-year long orbit– is currently on its method towards perihelion (its closest technique to the Sun) in 2076. There are no missions to Sedna in the works simply yet, however astronomers are beginning to prepare for the possibility, and the ideal launch date for such a mission is approaching fast, with 2 of the finest launch windows coming up in 2029 and 2034.
As finest we can inform from a range, Sedna is about the very same size as Ceres, the largest things in the asteroid belt, however its composition and origins are very various. Possibly the most high-profile theory is the possibility that a yet unidentified ninth planet, perhaps ten times the size of Earth, interfered with Sednas orbit and swept it and a number of other items out into extremely lengthened orbits. Checking out Sedna probably wont resolve this specific mystery, but it will inform us a lot about the structure of these extreme trans-Neptunian things.
Object 90377 Sedna– a distant trans-Neptunian item known finest for its extremely elliptical, 11,390-year long orbit– is presently on its way towards perihelion (its closest method to the Sun) in 2076. After that, Sedna will swing out into deep space once again and wont be back for millennia, making this flyby an once-in-a-lifetime (or, once in ~ 113 life times) chance to study an item from the far reaches of our solar system. There are no objectives to Sedna in the works just yet, but astronomers are starting to plan for the possibility, and the ideal launch date for such an objective is approaching fast, with 2 of the best launch windows showing up in 2029 and 2034.