Scrutable

Obviously I was tempted to put this in weighty matters.

Asteroid 33 Polyhymnia seems to have a density of around 75 g/cm3 which is way heavier than any element so far discovered, however the observations needed to make this calculation are difficult owing to its small size and have only been done once.

This article seems to suggest that super heavy elements may exist around Z=164 :


I would like to read the research paper it quotes: Superheavy elements and ultradense matter, Evan LaForge, Will Price & Johann Rafelski.
https://link.springer.com/article/10.11 ... 23-04454-8
However this is behind a paywall, anyone know of anywhere with a free copy?

Is this it? https://arxiv.org/abs/2306.11989

Surely measuring the volume of an asteroid must have quite large error bars, unless it’s really well lit.

Grumble wrote: ↑

Mon Oct 16, 2023 5:38 am

Surely measuring the volume of an asteroid must have quite large error bars, unless it’s really well lit.

And it really depends on what the spin axis is. Imagine a cigar shaped object spinning around its long axis, which is pointing almost exactly in your direction, vs a cigar spinning around a short axis at 90 degrees to you.

philip wrote: ↑

Sun Oct 15, 2023 11:52 pm

Is this it? https://arxiv.org/abs/2306.11989

Thanks.

Accessing an obscure source, I find that these data on the mass and size of 33 Polyhymnia were established over a decade ago. In all that time, no other scientists proposed it was made of ultra-dense matter, as opposed to measurement shortcomings. How dull of them.

dyqik wrote: ↑

Mon Oct 16, 2023 7:14 am

Grumble wrote: ↑

Mon Oct 16, 2023 5:38 am

Surely measuring the volume of an asteroid must have quite large error bars, unless it’s really well lit.

And it really depends on what the spin axis is. Imagine a cigar shaped object spinning around its long axis, which is pointing almost exactly in your direction, vs a cigar spinning around a short axis at 90 degrees to you.

It has an orbital period of a little under 5 years. It won't be pointing its spin axis at us all the time. We should have plenty of time when we get side-on views, if we looked.

But it does have a rather eccentric orbit. We'd probably only get a decently close approach for a few weeks about every 10 years or so. And then someone has to be bothered to be trying to look. So you can imagine a scenario where it tends to be pointing its narrow end, if it has one, in roughly our direction around perihelion, or else just whenever we happened to be occasionally looking.

IvanV wrote: ↑

Mon Oct 16, 2023 3:49 pm

Accessing an obscure source, I find that these data on the mass and size of 33 Polyhymnia were established over a decade ago. In all that time, no other scientists proposed it was made of ultra-dense matter, as opposed to measurement shortcomings. How dull of them.

The article cited by Wikipedia acknowledges that the calculated density for 33 Polyhymnia is 'unrealistic' (page 20)
https://arxiv.org/pdf/1203.4336.pdf

The source of the mass is this paper here from 2010 -
https://arxiv.org/pdf/1011.4419.pdf - the method seems to rely on measuring the perturbations in the asteroid's orbit against a dynamic model of the Solar System. I notice that there is no figure for the mass of 33 Polyhymnia in the most recent (2019) paper.