Is it a question of waiting ages for one interstellar object and then two turn up at once or are these a lot more frequent than we realised?
Boffins examine interstellar comet Borisov to find out what its home was like. Pretty unpleasant, it seems
Astronomers have for the first time measured the chemical composition of an interstellar comet: 2I/Borisov, which strayed into our Solar System last year. Two separate studies published in Nature Astronomy on Monday revealed the speeding icy ball of gas and dust contained a surprising amount of unpleasant carbon monoxide. …
COMMENTS
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Tuesday 21st April 2020 13:29 GMT mr.K
I can't say that they are more frequent than we realised or not, but they are more frequent than we have been able to detect. Think about it, it has taken us a great while to detect most objects in our solar system. They are here for a long time while these just pass through, quite quickly. To be able to detect them we need several things to happen. They need to come close enough, be big enough and bright enough, and we need to look in their direction over a period of time. If we are really lucky they get so close that they start to send out gas and dust making them much more easy to spot. Also, and here I am guessing it will help if they come in close to the plane of our solar system, since we have more cameras looking for things in that plane. (not sure if plane is the right word here, plane of orbits..dunno)
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Wednesday 22nd April 2020 17:41 GMT Michael Wojcik
Re: Temperature for yokels
Fahrenheit is at least based on a sensible design - reference points (32 and 96) separated by a power of two so that thermometers could be graduated by equal subdivision and then the scale reflected to extend it. Celsius is just the usual powers-of-10 digital rubbish.
And what's wrong with Rankine, eh?1
But as usual Randall got here first.
I think the Reg needs to add a temperature unit to its standard units. Maybe "heat in proportion to a nice cup of tea". My back-of-the-envelope calculations suggests CO freezes at around 0.22 cuppa.2
1OK, in all seriousness, I recognize the utility of Kelvin in SI.
2I arbitrarily decided that a nice cup of tea is about 26 °Rø.
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Tuesday 21st April 2020 16:28 GMT Draco
Why a red dwarf?
The claim is, “We can infer cold temperature from carbon monoxide because carbon monoxide ice has an extremely low freezing temperature ... If we see lots of carbon monoxide preserved in the comet, that means the comet must have both formed under extremely low temperature where lots of carbon monoxide ice could exist, and never heated significantly above that low temperature ever since..."
Ok, I buy that. However, couldn't the comet have formed in a region similar to the Kuiper belt - very far away from the parent star (which may or may not be a red dwarf) - where it is very cold regardless if the star is a red dwarf or not?
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Tuesday 21st April 2020 18:16 GMT mr.K
Re: Why a red dwarf?
“We think it’s more likely to be the latter case – it comes from a cold red dwarf because there are far more red dwarfs in our Milky Way galaxy than other hotter stars. However, we are still far from saying exactly what’s going on around its host star when planets formed there."
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Wednesday 22nd April 2020 08:59 GMT Wilseus
Re: Why a red dwarf?
"they are by their very nature difficult to see"
Yes, it rather puts that into perspective when you realise that none are generally visible to the naked eye, although it's possible that on an exceptionally good night, in an place with zero light pollution some people might just be able to glimpse Lacaille 8760.
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