Found a planet that gets really close to a neutron star

[Ravenov]

It's in a really eccentric orbit, so it only gets this close once every ~16 days.

I was hanging around the area for over a week, since it was on the outward part of the orbit when i first found it.

Was unsure of exactly when the closest pass would be and nearly missed it as the orbit seemed to speed up the closer it got to the star. At 3:30am last night the planet was 26Ls from the neutron, giving an average approach speed nearly 3.5Ls per hour. I calculated it was moving less than 2Ls per hour based on the 10 hours or so that I observed yesterday. The system itself is around 15KLy from Earth.

The orbit itself goes between the jet cones, so no danger of cooking the ship.

This was about the closest i recorded, also showing location and time of day, 11AM on the 15th December. By my estimation, the next close pass will be on January 1st at around 3am GMT.

System map showing orbital details. Of note is the Orbital Eccentricity; A value of 0.0 will be a perfectly circular orbit, the closer the number is to 1 the more elliptical it will be. 0.98 is very elliptical.

 

[Orvidius]

Of note is the Orbital Eccentricity; A value of 0.0 will be a perfectly circular orbit, the closer the number is to 1 the more elliptical it will be. 0.98 is very elliptical.

Wow, that's very eccentric. Without doing any of the actual math, I'm guessing that the apoapsis (aphelion, or furthest extent) is probably at least 100x the distance of the periapsis (perihelion, or closest approach). And yet it's still only 16 days for the entire orbit? It will be moving very quickly during its closest approach.

 

[Ravenov]

Wow, that's very eccentric. Without doing any of the actual math, I'm guessing that the apoapsis (aphelion, or furthest extent) is probably at least 100x the distance of the periapsis (perihelion, or closest approach). And yet it's still only 16 days for the entire orbit? It will be moving very quickly during its closest approach.

Looking through my screenshots, the furthest out i recorded was 142Ls, but i think that was just past or just before apoapsis.

This is the best pic of the orbit i could capture...

Edit, and yep, it was moving fast enough across the sky to be obvious. I was in low orbital cruise looking for somewhere to land and it was difficult because by the time i'd got low enough to drop the star had shifted too much.

 

[Jackie Silver]

Was unsure of exactly when the closest pass would be and nearly missed it as the orbit seemed to speed up the closer it got to the star.

Yeah, they do that.

 

[thundernuns]

EDIT:Nevermind

What's the neutron star's mass, out of interest?

 

[Han Zulu]

Was unsure of exactly when the closest pass would be and nearly missed it as the orbit seemed to speed up the closer it got to the star.

Kepler's law of planetary motions. Learned it in Astronomy class.

If I remember right, the distance and speed relates to the arc-area or something like that.

 

[thundernuns]

Ok, after doing some quick calculations (thanks Wolfram), assuming the neutron star has 0.5 sol masses, at the close approach of 26ls, the planet should be travelling at 117.7km/s or 263,000mph, or 1.7 Helios 2 speeds, the fastest man made object (as of 2017). As a comparison, Earth orbits at 29.8km/s or 66,000 mph.

HOWEVER...take this with a pinch of salt as I am by no means a physicist, plus the equations didn't take into account the mass of the planet as it is fairly negligible compared to the mass of the star. Plus the previously mentioned Kepler laws also mean in reality it will orbit slightly slower than calculated.

Anyway, if anyone thinks I'm wrong then correct me, there were some VERY big numbers involved [big grin]

 

[Ravenov]

Yeah, they do that.

Kepler's law of planetary motions. Learned it in Astronomy class.

If I remember right, the distance and speed relates to the arc-area or something like that.

Yeah i had an inkling that would be the case, hence my fudge factor in when i logged on to check. Right now (~11 hours from closest pass) the planet has moved on to 34Ls from the neutron, so still moving at a fair lick.

What's the neutron star's mass, out of interest?

And the black hole that is the primary body in system, not that it has any impact.

 

[Ravenov]

Ok, after doing some quick calculations (thanks Wolfram), assuming the neutron star has 0.5 sol masses, at the close approach of 26ls, the planet should be travelling at 117.7km/s or 263,000mph, or 1.7 Helios 2 speeds, the fastest man made object (as of 2017). As a comparison, Earth orbits at 29.8km/s or 66,000 mph.

HOWEVER...take this with a pinch of salt as I am by no means a physicist, plus the equations didn't take into account the mass of the planet as it is fairly negligible compared to the mass of the star. Plus the previously mentioned Kepler laws also mean in reality it will orbit slightly slower than calculated.

Anyway, if anyone thinks I'm wrong then correct me, there were some VERY big numbers involved [big grin]

It got to within 0.8 Ls, so i'm guessing it was going significantly faster at that point...

 

[thundernuns]

It got to within 0.8 Ls, so i'm guessing it was going significantly faster at that point...

:O
Well according to that, the planet would be going 1,659,000 mph...with an escape velocity for the system of 1,663,000 mph (for a star of 0.5 sol mass, bearing in mind). That thing is almost out of there. In fact it has 70% of the speed of the escape velocity of the galaxy

Edit:Thanks for neutron star stats, I imagine it would be going even faster if it's that massive. I'm not working it out though again though [haha]

 

[malenfant]

Very nice, I was wondering if there were any planets that got close to a Neutron Star in a similar way to Monde de la Mort's orbit around its WD primary! But if that's 0.14 AU and an eccentricity of 0.9891 then that means the orbit ranges from 0.77 ls to 0.278AU (139 ls)! I don't think that's close enough to get really up close and personal with the neutron star (since it is only about 10 km across) - is that even within the NS' exclusion zone? - but that's still the closest I've ever heard of a planet approaching a WD!

 

[Jackie Silver]

I wonder if there are any circumstances with highly elliptical orbits where you could land on a planet and then ride it *through* the exclusion zone of a star?

 

[osser]

Jackie, I was just thinking the same thing.
How cool would it be to be landed on that when it slings around that Neutron.
Would the dismissed ship be damaged?

 

[Leif_Erikson]

That is a great find.There must be a NS system out there in the stellar forge with a moon that you could land on and watch the Neutron Star rise and set in a minute !

 

[Jackie Silver]

I would love to see this planet at its next close pass. If anybody is likely to be there with a spare crew seat on the 1st of January please let me know!

 

[Ravenov]

I would love to see this planet at its next close pass. If anybody is likely to be there with a spare crew seat on the 1st of January please let me know!

I might still be out here, especially as i have a better chance of knowing when the pass will happen (assuming i worked out the maths properly).

 

[Pyrotiger]

3,000 LY away. Might make a diversion...

 

[Orvidius]

Ok, after doing some quick calculations (thanks Wolfram), assuming the neutron star has 0.5 sol masses, at the close approach of 26ls, the planet should be travelling at 117.7km/s or 263,000mph, or 1.7 Helios 2 speeds, the fastest man made object (as of 2017). As a comparison, Earth orbits at 29.8km/s or 66,000 mph.

Yeah, anything with such a high eccentricity will get very close to its escape velocity. An eccentricity of 1.0 or higher is an escape trajectory instead of an orbit, so at 0.98, it'll get close to the escape velocity at apoapsis. It's interesting to think about how a planetary body might end up in that orbit. A close interaction with another body that flung them both, with one escaping and the other not quite escaping is a possibility, or an interaction with a rogue planet. It's also possible that this was the rogue planet, which was then captured. Cool stuff.

 

[Jackie Silver]

I might still be out here, especially as i have a better chance of knowing when the pass will happen (assuming i worked out the maths properly).

Cool, that would be great - I'd visit myself but I need to be heading the opposite direction to make the DECE meetups.

 

[varonica]

It's also possible that this was the rogue planet, which was then captured. Cool stuff.

Very likely. if it was just the neutron star and the planet no, capture is impossible in a 2 body system (assuming no interference from collisions or dust), but with the black hole easily possible.