I got excited when I read a short piece from New Scientist about this "huge and previously unknown object entering our solar system that will reach the orbit of Saturn in 2031"! Wanting to know more, I searched and found this from Nasa: https://ssd.jpl.nasa.gov/sbdb.cgi?sstr= ... og=0;cad=0
It will reach "the orbit of Saturn", but that's the furthest it will come in. I don't suppose that far out that it will even develop a comet's tail!
Disapponted!
John
Re: 2014 UN271
Posted: Wed Jun 23, 2021 2:05 pm
by Chris Peterson
JohnD wrote: ↑Wed Jun 23, 2021 9:57 am
I got excited when I read a short piece from New Scientist about this "huge and previously unknown object entering our solar system that will reach the orbit of Saturn in 2031"! Wanting to know more, I searched and found this from Nasa: https://ssd.jpl.nasa.gov/sbdb.cgi?sstr= ... og=0;cad=0
It will reach "the orbit of Saturn", but that's the furthest it will come in. I don't suppose that far out that it will even develop a comet's tail!
Disapponted!
John
It might well develop a tail, particularly if (as is very possible) this is its first visit to the inner system.
JohnD wrote: ↑Wed Jun 23, 2021 9:57 am
I got excited when I read a short piece from New Scientist about this "huge and previously unknown object entering our solar system that will reach the orbit of Saturn in 2031"! Wanting to know more, I searched and found this from Nasa: https://ssd.jpl.nasa.gov/sbdb.cgi?sstr= ... og=0;cad=0
It will reach "the orbit of Saturn", but that's the furthest it will come in. I don't suppose that far out that it will even develop a comet's tail!
Disapponted!
It might well develop a tail, particularly if (as is very possible) this is its first visit to the inner system.
https://en.wikipedia.org/wiki/2014_UN271 wrote:
<<2014 UN271's absolute magnitude of 7.8 suggests the body could be in the range of a 100 km in diameter. However, if cometary activity was present at the time of the original observations it could be significantly smaller. On 22 June 2021, cometary activity was observed and reported by the Las Cumbres Observatory in California and the SkyGems Remote Telescope in Namibia. The object's heliocentric distance was 20.18 AU and it was observed to be brighter than predicted, with a slightly elongated coma reported by SkyGems to be approximately 15 arcseconds wide. Cometary activity has previously been observed as far as 25.8 AU from the Sun on a few comets, for example C/2010 U3 (Boattini). Cometary activity at these distances can be generated by supervolatiles such as CO and CO2.>>
JohnD wrote: ↑Wed Jun 23, 2021 9:57 am
I got excited when I read a short piece from New Scientist about this "huge and previously unknown object entering our solar system that will reach the orbit of Saturn in 2031"! Wanting to know more, I searched and found this from Nasa: https://ssd.jpl.nasa.gov/sbdb.cgi?sstr= ... og=0;cad=0
It will reach "the orbit of Saturn", but that's the furthest it will come in. I don't suppose that far out that it will even develop a comet's tail!
Disapponted!
It might well develop a tail, particularly if (as is very possible) this is its first visit to the inner system.
https://en.wikipedia.org/wiki/2014_UN271 wrote:
<<2014 UN271's absolute magnitude of 7.8 suggests the body could be in the range of a 100 km in diameter. However, if cometary activity was present at the time of the original observations it could be significantly smaller. On 22 June 2021, cometary activity was observed and reported by the Las Cumbres Observatory in California and the SkyGems Remote Telescope in Namibia. The object's heliocentric distance was 20.18 AU and it was observed to be brighter than predicted, with a slightly elongated coma reported by SkyGems to be approximately 15 arcseconds wide. Cometary activity has previously been observed as far as 25.8 AU from the Sun on a few comets, for example C/2010 U3 (Boattini). Cometary activity at these distances can be generated by supervolatiles such as CO and CO2.>>
If I've learned anything from years of comet observation, it's that I can't take predictions about brightness and other features very seriously. Comets are highly unpredictable in their behavior. Some that were barely discussed turned out to be spectacular, others that were predicted to be great fizzled. It's enough to know they're coming; beyond that, we just wait and see.
Just been back to the Nasa page and fiddled with the controls to look from the Ecliptic. That shows that the orbit of 2014 UN271 is almost at right angles to that plane, so it comes from way, way outside! Has the orbit been observed for long enough to tell if it is one of the Sun's children or another Oumuamua?
Re: 2014 UN271
Posted: Thu Jun 24, 2021 11:40 am
by Chris Peterson
JohnD wrote: ↑Thu Jun 24, 2021 10:16 am
Just been back to the Nasa page and fiddled with the controls to look from the Ecliptic. That shows that the orbit of 2014 UN271 is almost at right angles to that plane, so it comes from way, way outside! Has the orbit been observed for long enough to tell if it is one of the Sun's children or another Oumuamua?
It's in an elliptical orbit. Not extrasolar. A body from the Oort cloud.
Re: 2014 UN271
Posted: Thu Jun 24, 2021 12:40 pm
by JohnD
Thanks, Chris.
Nasa's Dragonfly mission will land a flying rover on Titan in 2036. By then, UN271 will be halfway to the orbital distance of Neptune, and well out of the ecliptic. Would you think that anything could be 'piggy-backed' onto the Dragonfly carrier that could be sent towards the comet?
John
Re: 2014 UN271
Posted: Thu Jun 24, 2021 1:26 pm
by neufer
JohnD wrote: ↑Thu Jun 24, 2021 12:40 pm
Nasa's Dragonfly mission will land a flying rover on Titan in 2036. By then, UN271 will be halfway to the orbital distance of Neptune, and well out of the ecliptic. Would you think that anything could be 'piggy-backed' onto the Dragonfly carrier that could be sent towards the comet?
1) The Europeans could always do a rush job on their Comet Interceptor.
2) The Chinese have loads of money and would certainly love to pull off a first.
https://en.wikipedia.org/wiki/Comet_Interceptor wrote:
<<The Comet Interceptor is a robotic spacecraft mission led by the European Space Agency (ESA) planned for launch in 2029. The spacecraft will be "parked" at the Sun-Earth L2 point and wait for up to three years for a long-period comet to flyby at a reachable trajectory and speed.
Long-period comets have highly eccentric orbits and periods ranging from 200 years to thousands of years, so they are usually discovered only months before they pass through the inner Solar System and return to the distant reaches of the outer Solar System, which is too little time to plan and launch a mission. Therefore, ESA will "park" the Comet Interceptor spacecraft on a stable halo orbit around the Sun-Earth L2 point and wait for the discovery of a suitable comet that it can reach for a close flyby.
The mission's primary science goal is stated as "to characterise, a dynamically-new comet, including its surface composition, shape, structure, and the composition of its gas coma." A few weeks before the comet flyby, the main spacecraft (spacecraft A) will deploy two small probes (B1 and B2) to venture even closer to the target, carrying complementary instrument payloads and to sample the coma. Each of the three spacecraft will sample gas composition, dust flux, density, magnetic fields, and plasma and solar wind interactions, to build up a 3D profile of the region around the comet.>>
Re: 2014 UN271
Posted: Thu Jun 24, 2021 1:45 pm
by JohnD
Sun-Earth LaGrange L2 is a LONG way from Saturn's orbit, eve when it is outwards. Is that realistic, neufer?
Re: 2014 UN271
Posted: Thu Jun 24, 2021 2:12 pm
by neufer
JohnD wrote: ↑Thu Jun 24, 2021 1:45 pm
Sun-Earth LaGrange L2 is a LONG way from Saturn's orbit, eve when it is outwards. Is that realistic, neufer?
The only purpose of going to L2 is to wait around for a "comet of interest" but they already have a comet of interest
(Falcon Heavy can launch 6x the payload (into Earth orbit) of the Comet Interceptor's planned Ariane 62 rocket.)
Re: 2014 UN271
Posted: Thu Jun 24, 2021 2:23 pm
by Chris Peterson
JohnD wrote: ↑Thu Jun 24, 2021 12:40 pm
Thanks, Chris.
Nasa's Dragonfly mission will land a flying rover on Titan in 2036. By then, UN271 will be halfway to the orbital distance of Neptune, and well out of the ecliptic. Would you think that anything could be 'piggy-backed' onto the Dragonfly carrier that could be sent towards the comet?
Realistically, no. The Dragonfly mission is on the ecliptic. The delta-V required to match a body that is basically perpendicular to that would be huge. The only possibility of an interception would be some kind of flyby as the comet is crossing the ecliptic. But that seems very unlikely to work out.
If there were some powerful reason to study this object (which I don't think there is) it would be cheaper and easier to launch a dedicated probe from Earth.
Re: 2014 UN271
Posted: Fri Jun 25, 2021 8:57 am
by JohnD
You don't think this minor planet sized comet is of that much interest, Chris? Other missions have been launched (OsirisREX, Hayabusa) to bring back specimens of primordial material. Something from the Oort Cloud is as primordial as they come!
A specimen return mission would seem beyond possibility from so far out. Will you and you astronomy colleagues be able to learn as much from here as a probe could much closer up?
JohnD wrote: ↑Fri Jun 25, 2021 8:57 am
You don't think this minor planet sized comet is of that much interest, Chris? Other missions have been launched (OsirisREX, Hayabusa) to bring back specimens of primordial material. Something from the Oort Cloud is as primordial as they come!
A specimen return mission would seem beyond possibility from so far out. Will you and you astronomy colleagues be able to learn as much from here as a probe could much closer up?
It's not that it isn't an object of interest. It's that it provides no special interest. Pristine comets from the Oort cloud are not uncommon at all. What's unusual about this one is its size, but that alone doesn't seem to offer a reason to inspect it closely. A mission to study an Oort cloud comet would be better specified, prepared, and then launched when a convenient one with a suitable orbit (and probably a perihelion much closer to the Earth) was detected.
JohnD wrote: ↑Fri Jun 25, 2021 8:57 am
You don't think this minor planet sized comet is of that much interest, Chris? Other missions have been launched (OsirisREX, Hayabusa) to bring back specimens of primordial material. Something from the Oort Cloud is as primordial as they come! A specimen return mission would seem beyond possibility from so far out. Will you and you astronomy colleagues be able to learn as much from here as a probe could much closer up?
It's not that it isn't an object of interest. It's that it provides no special interest. Pristine comets from the Oort cloud are not uncommon at all. What's unusual about this one is its size, but that alone doesn't seem to offer a reason to inspect it closely. A mission to study an Oort cloud comet would be better specified, prepared, and then launched when a convenient one with a suitable orbit (and probably a perihelion much closer to the Earth) was detected.
Nothing would better prepare for such a future complex mission than an old fashion comet flyby of C/2014 UN271 with new advanced instruments, power sources and rockets. C/2014 UN271 appears to be either particularly large or particularly active (or both) and it would be a shame if no one took advantage of this opportunity.
JohnD wrote: ↑Fri Jun 25, 2021 8:57 am
You don't think this minor planet sized comet is of that much interest, Chris? Other missions have been launched (OsirisREX, Hayabusa) to bring back specimens of primordial material. Something from the Oort Cloud is as primordial as they come! A specimen return mission would seem beyond possibility from so far out. Will you and you astronomy colleagues be able to learn as much from here as a probe could much closer up?
It's not that it isn't an object of interest. It's that it provides no special interest. Pristine comets from the Oort cloud are not uncommon at all. What's unusual about this one is its size, but that alone doesn't seem to offer a reason to inspect it closely. A mission to study an Oort cloud comet would be better specified, prepared, and then launched when a convenient one with a suitable orbit (and probably a perihelion much closer to the Earth) was detected.
Nothing would better prepare for such a future complex mission than an old fashion comet flyby of C/2014 UN271 with new advanced instruments, power sources and rockets. C/2014 UN271 appears to be either particularly large or particularly active (or both) and it would be a shame if no one took advantage of this opportunity.
Well, flybys are rather limiting. Parking missions are much better, and perfectly possible given a suitable orbit for the cometary body. Which maybe this one has, or maybe doesn't. But I don't see much value in the size of this comet. And like I said, Oort cloud comets are common enough. The important thing is not to compromise an existing mission, and not to cobble together a new mission too quickly.
neufer wrote: ↑Fri Jun 25, 2021 3:50 pm
Nothing would better prepare for such a future complex mission than an old fashion comet flyby of C/2014 UN271 with new advanced instruments, power sources and rockets. C/2014 UN271 appears to be either particularly large or particularly active (or both) and it would be a shame if no one took advantage of this opportunity.
Well, flybys are rather limiting. Parking missions are much better, and perfectly possible given a suitable orbit for the cometary body. Which maybe this one has, or maybe doesn't. But I don't see much value in the size of this comet. And like I said, Oort cloud comets are common enough. The important thing is not to compromise an existing mission, and not to cobble together a new mission too quickly.
If C/2014 UN271 is big then any flyby will have a much better visual view of it.
If it is active then a flyby could gain a much better scientific knowledge of it.
NASA has done an excellent job with its careful slow & steady projects. But they also proves to be both expensive & nail biting while often requiring extensive delays (i.e., JWST).
SpaceX has demonstrated the advantages of a more quick & dirty approach and C/2014 UN271 would seem to be a wonderful opportunity for Falcon Heavy (or the Chinese).
A first is a first is a first. Whether pristine Oort cloud comets are unique or just same old, same old let's find out now
neufer wrote: ↑Fri Jun 25, 2021 3:50 pm
Nothing would better prepare for such a future complex mission than an old fashion comet flyby of C/2014 UN271 with new advanced instruments, power sources and rockets. C/2014 UN271 appears to be either particularly large or particularly active (or both) and it would be a shame if no one took advantage of this opportunity.
Well, flybys are rather limiting. Parking missions are much better, and perfectly possible given a suitable orbit for the cometary body. Which maybe this one has, or maybe doesn't. But I don't see much value in the size of this comet. And like I said, Oort cloud comets are common enough. The important thing is not to compromise an existing mission, and not to cobble together a new mission too quickly.
If C/2014 UN271 is big then any flyby will have a much better visual view of it.
If it is active then a flyby could gain a much better scientific knowledge of it.
NASA has done an excellent job with its careful slow & steady projects. But they also proves to be both expensive & nail biting :ohno: while often requiring extensive delays (i.e., JWST).
SpaceX has demonstrated the advantages of a more quick & dirty approach and C/2014 UN271 would seem to be a wonderful opportunity for Falcon Heavy (or the Chinese).
A first is a first is a first. Whether pristine Oort cloud comets are unique or just same old, same old let's find out now :!:
There is a steady stream of Oort cloud bodies to choose from. My point is that there is nothing obvious that makes this the best choice for such a mission. And if activity is important, we'd likely be better choosing one that will come closer to the Sun. And that also allows for quicker access.
Re: 2014 UN271
Posted: Sat Jun 26, 2021 5:31 pm
by neufer
neufer wrote: ↑Fri Jun 25, 2021 5:04 pm
If C/2014 UN271 is big then any flyby will have a much better visual view of it.
If it is active then a flyby could gain a much better scientific knowledge of it.
NASA has done an excellent job with its careful slow & steady projects. But they also proves to be both expensive & nail biting while often requiring extensive delays (i.e., JWST).
SpaceX has demonstrated the advantages of a more quick & dirty approach and C/2014 UN271 would seem to be a wonderful opportunity for Falcon Heavy (or the Chinese).
A first is a first is a first. Whether pristine Oort cloud comets are unique or just same old, same old let's find out now
Chris Peterson wrote: ↑Fri Jun 25, 2021 5:08 pm
There is a steady stream of Oort cloud bodies to choose from. My point is that there is nothing obvious that makes this the best choice for such a mission. And if activity is important, we'd likely be better choosing one that will come closer to the Sun. And that also allows for quicker access.
There is an irregular stream of Oort cloud bodies to choose from.
We have already seen many comets (up close) that are active because they are quite warm. We have yet to see a comet (up close) that is already visibly active at a solar distance of 20+ AU.
Alternatively, we could cobble together a probe to C/2017 K2:
https://en.wikipedia.org/wiki/C/2017_K2 wrote:
<<C/2017 K2 (PANSTARRS) is an [18 km wide] Oort cloud comet with a hyperbolic orbit, discovered in May 2017 at a distance beyond the orbit of Saturn when it was 16 AU (2.4 billion km) from the Sun. On 17 September 2020, morphological studies of the inner coma, observed on 12 September 2020, were reported, noting that two jet-streamed structure were emitted from the nucleus and, as well, that the length of the tail was about 800,000 km long. Around 6 July 2022, the comet will cross the celestial equator, and then around 14 July 2022, it will pass 1.8 AU from Earth and shining at 7.0 magnitude at that time. It will reach perihelion around 19 December 2022, close to the orbit of Mars, and will possibly be visible to naked eye at 6.0 magnitude.>>
while often requiring extensive delays (i.e., JWST).