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18 July 2018 @ 09:41 am
_Crux_ part 1  
I think I've already posted this, but what the heck, a lot of you are new here.

Crux

Chapter One

In which everyone realizes they miscalculated

The neutrino alarm gave them a split second to dive for the most protected part of the station.

Odessa swung through the hatch and twisted around the shielded corner into the crew sleeping area; Don, on her heels, hit the close button. Clint and Mathew were doing the same from the lab side of the station. Kenya and Lonnie collided as they tumbled out of their respective beds.

Odessa punched off the radiation alarm, and then the temperature alert. It was hot and getting hotter. Already.

Clint Coutts, the Chief Astronomer smiled crookedly. "Well, I guess we should have packed sooner."

They had been scheduled to leave in three months as Alpha Crux B's core approached the Chandrasekar limit. The station, and its unmanned partner loafed along in orbit around Alpha Crux B, the incipient supernova.

_Scratch the incipient._ Odessa thought. Crux B was exploding now and they were much too close. They were only a little further from the A component of the close double star system – they hadn't expected the station to be in use long enough for the unstable orbit to matter.

She turned to the atmospheric controls and switched the cooler circuits to the heat sump. "It's forty degrees in here already." The heat radiator fins were probably melting.

"The station was designed with a safety margin that allowed for possible early ignition." Clint's eyes were on the temperature gauge. Sweat ran down his face.

"Forty-five."

"I don't believe this. It can't have accumulated enough iron to have gone over the limit already." Don protested.

"We have discussed the time lag in detecting the core buildup, Don." Odessa was stripping out of her baggy overalls as she spoke. "As fast as the temperature is rising, I think it's time for the suits." She was dripping with sweat, and jerked her hand back from the hot latch. The metal was even hotter than the air. She grabbed the discarded overalls and used them to insulate her hand as she popped open the suit storage locker.

Kenya wiped her face angrily. "What does it matter? Why are we even bothering? The shockwave will be here in nine days. We're dead."

"A little over nine days, if we are correct about the wavefront blasting out at 0.23c. And on top of that is the time required for the energy to work its way out from the core. The pressure and inertia of the upper layers will slow it. We've never managed to figure out how fast these later stages take." Clint was studying the controls. "The temps are too high for us mere biological beings, but the station keeping engines are still working. Our best bet is to get the bulk of the A pair between us and the Supernova."

Odessa grabbed the first suit and retreated. One size fit all emergency suits. They weren't expected to do any outside work. The one repair they'd needed, they'd hired one of the local asteroid miners to come and deal with.

"The miners." She shoved a hot damp leg into the suit as she hopped away from the locker to give the others room. "Any idea where they were?"

"All over, as usual."

***

There were eight of them brave enough to turn off their electronics and drop through Bosco's magnetosphere to bob for apples. Except the apples they hoped to scoop up were metal. Iridium and Rhodium if they were lucky.

Jamie was deep into the mess, maneuvering gently by sight through the ice chunks of the inner ring, trailing a magnetized net to hopefully make him a rich man when light like the Wrath of God blazed off of every reflective surface. He ducked and tripped the impact shield by feel. Blinked watering eyes. Eyes open or closed, he couldn't see anything but some big white spots. "This is not good." He was sweating like a pig, his nerves making it feel like the whole ship had heated up.

He reached out for the radio, but stopped. If he unpacked it now, and didn't get it packed again before the magnetopause, he'd fry it. "Oh, hell, I'm so screwed anyway." He unclipped the plastic latch, and opened the layered box. Found the power cord by feel, plugged it in ditto. Flipped the switch.

". . . I'll try and get into the shadow, it's the best bet. Out." That was Luke on the Bounding Main.

"Cougar here. I'm in the shadow and dropping to put myself below the rings when I emerge. Out."

Jamie pushed the send button. "Bellefleur here. What was that?"

"B went supernova." Jeri Kanagi's flat voice was easily recognizable. "Couldn't be anything else. God knows how many rads of X-rays and Gamma rays we just picked up."

"Nut here." Allan Almond's voice was high and worried. "The magnetosphere should have protected us. We just got the light and heat, right?"

Silence.

Jamie finally broke it, "I think they get deflected, don't they? The X-rays have something to do with the auroras, they get defected to the north I think, but the gammas are deflected away altogether, aren't they?"

More silence.

"Well, I certainly hope so." That sounded like Althea to him.

"How many of us are here, inside the magnetosphere?" Jamie asked, suddenly wondering how he was going to maneuver to stay inside the magnetosphere. Not to mention out of a suddenly viciously bright sun. He squinted. The white spots were cooling off and had red halos now, and he could see light and dark and linear things that were the edges of his control panel, in between them. A thump shuddered through the ship as it bumped an iceberg. His orbit was just eccentric enough to get him out of the magnetosphere, so as to minimize his velocity difference with the ring rubble. He needed to slow just a bit more, and as Zack had said, get below something. This thump had been substantial enough to be promising – if he could see to maneuver.

"Was that Althea or Melinda a second ago?" Luke asked.

"Althea."

"I'm here too." another feminine voice, "Melinda in Withering High."

"The Wizard of Odd is here, as well." Roslyn had _the_ sexiest voice in space. No argument from anyone who had ever heard her. She claimed to be closing in on eighty years of age.

"OK, eight of us." Jamie said. "Now, how many of us are going to admit to being flash blinded and in trouble?"

After a hesitation, he cleared his throat. "Can anyone see even half decently?"

"Mine's clearing up fast," Zack said, "But I'm on the night side and I don't see anyone else."

"OK, I guess I can maybe see well enough to find a rock to hide under." Jamie unsafed his navigation panel. Swinging his head around, trying look around the blind spots, he finally decided that he'd lucked into one of the larger chunks of ring material. He opened the visual cams as well, dimming them, making sure he could tell which side was sunward. The maneuvering jets hissed as he cautiously dropped and scooted under the iceberg. He could feel the temps drop in the ship and hit the forward thrusters to keep him in the shadow. He was still drifting though, his orbit not matched to the berg's. Back to trying to decipher the navigation panel . . . he rotated the Bellefleur carefully and fired a brief burst from the main engines.

"Well, that'll do for now." He carefully extended the range of his radar. "So, where's everyone else?"

In careful stages, and multiple input, they all managed to get under cover, and their orbits adjusted enough to keep them in the rings.

"But what are we going to do in the long run?" Roslyn asked.

***

They couldn't even leave quarters to erect an antennae. Their quarters were holding steady at 70 to 75 degrees centigrade, the outer parts of the station were running around ninety. They'd used up all their spa and resort, and station-wide sauna jokes two days ago.

The slow steady ion drive had finally pulled them from their orbit and thrown them at the close binary. They'd dropped all the exterior modules, to lower the mass they were moving. All their scientific instruments were fried, anyway and they daren't try a replacement antennae to see if they could pick up any of the more distant stations. Pity the one inhabited station in the chain had been one of the closest.

"The problem is the fuel." Clint poked morosely at the rudimentary control panel. "We use water, and we're going to be out about the time we need to maneuver to get behind the suns."

"So, there's no hope of, say, getting to the wormhole and hanging about hoping someone will come and haul us away?" Odessa hated to ask. She really didn't want to hear the answer.

"No. The jump point's much further out. Even with a full load of water we couldn't reach it. I've maxed the engines out just trying to buy a bit more time." He thumped his helmet with a gloved hand, probably trying to reflexively run his hand through his hair. Or maybe pull it.

"Well," Kenya smiled with forced brightness, "We'll just have to hope the jumpship came early, has seen what we are doing and will come and rescue us."

Don was frowning. "Is there anyway to get close to Bosco? It's got rings of ice, all the outer moons are ice, for that matter."

"We could refuel." Lonnie brightened.

Clive sighed noisily. "Do not mistake a space station for a space ship. We are barely mobile, and not maneuverable by any reasonable definition of the word." He shrugged. "None the less, I'll try to aim for Bosco." his smile looked forced.

Odessa figured they didn't have enough water for even that. They were in an elliptical orbit around the A pair now, an orbit that would take them dangerously close to one of the pair at perihelion, but the gravity well that was pulling them in was also speeding them away from the worse danger at their backs.

How long does it take a star to explode? The question they had come here to study had suddenly become critical to their lives. Somewhere behind them most of the mass of a large star was lifting away from its own core, exploding outward. It would either catch them, or it wouldn't.

Odessa sat down in her cubby, a rotatable space that could be bed, office or entertainment center. The station was still spinning around its axis, so there was still an up and down for them. They had plenty of power for their various gadgets. She fired up her computer and wondered if she should write a letter to her sister. It seemed morbid. And useless, although she supposed that a follow up mission might someday find the station at the far end of its emergency orbit.

<Inventory>

She'd inventoried everything that ought to be available to them, everything in the central core area. She scrolled down and stopped at the radio. A radio frequency communicator. Voice only, integral antennae.

It was stored in the engine room tool closet. If it cooled down enough. If any of the asteroid miners had survived the gamma and X rays of the iron implosion. If they gave a damn, and would bring them any water.

They'd all chatted with them, there was a system wide bulletin board on the navigation satellite. It wasn't supposed to be used for idle chat, but the miners had used it, so the scientists had all introduced themselves, and occasionally exchanged views with the thirty or so diverse souls who had lived here.

She stuck her head back out of her cubby. "When was the last time any of you checked the miner's board? Does anyone have any idea how many of them left the system six months ago?"

Kenya looked up. "At least half of them. They had a betting pool, about whether that one or the next would be the last jump ship before the event. Most of them treated it like a joke. They didn't think it was going to happen at all, but it was a low cost ride. There wasn't anything here to keep any of them, and there are always richer systems to explore."

"I suppose they're all dead." Lonnie said, "The X-rays . . . except they're always dipping into Bosco's magnetosphere, aren't they? Looking for Rhodium in some of the nickel-iron bits mixed in with all the ice."

"So, some of them may have survived. We may be able to contact them, get them to bring us some water for fuel."

***

"That is so mind boggling." Jamie leaned back in the pilot's seat, watching the end of the world. The glowing cloud of the outer surface of the star had bulged out until it loomed over the double spark of the distant stellar pair. He had Horatio out of the cage and on his lap, but the guinea pig didn't seem very impressed. Jamie scratched the nape of his neck anyway, before getting up to put him back in his home, with his wife and children (eight this time). Lucky bugger. Until Jamie needed the air tested in one of the cargo holds.

"It's not as bright as I'd expected." Roslyn's beautiful voice caressed his ears. "And I didn't expect it break up like a solid, in hexagonal tiles like this either."

"I guess at these speeds the relatively cool surface acts more like a solid than a gas," Jamie guessed. "When it gets closer to the pair, I expect it'll stop being so text book neat, and scramble all up."

"Will they explode, too?" Zack joined in.

"Don't think so." Luke said, "Look at Sirius, the White Dwarf is a supernova remnant, didn't bother the star. Well, not long term anyway."

"I'm measuring it at close to a tenth of the speed of light." Roslyn said. "That means it'll be here in another forty days. Anybody have any good ideas?"

"Run for it." Jamie said. "We're out pretty far on the far side of the pair. Unfortunately the wormhole is even further out and off to the side."

"No use hoping a jumpship will show up in the nick of time, anyway." Zack argued.

"Any strong magnetic field will suck us through." Jamie pointed out. "It won't be pleasant, nor anything even resembling safe, but the options are looking pretty poor." And I can steer, sort of. Not that he was going to admit that. He knew all too well what happened to people with pilot talent. Lobotomized and hard wired into a jump ship's computers didn't sound like the sort of career he was interested in. "I grew up on a jump ship. I know how to prep for a jump, how to sync the magnetic fields."

"What would we do for wire? Space knows we've got enough iron for a core." Roslyn hummed a bit under her breath. "We'd have to cannibalize our nets."

"The wormhole's still too far away." Zack protested.

"There are two wormholes." Jamie pointed out. "The beta singularity is in close, the magnetospere is sort of tucked in there, the symmetry of the three star system being what it is, plus it's roughly in a direct line away from the blastfront. Twelve days, I figure. I think I'll see about that core – it's not like I've got anything else to do."

"Nobody's gone through Beta sing, Jamie. They didn't want to spend the money before the supernova – because it was a collapse risk." Zack hesitated. "I'm going to run some numbers, see if we can't make the wormhole. The wormhole. Alpha singularity." he added.

 
 
 
ekuah on July 18th, 2018 09:09 pm (UTC)
Scientific nitpicking
I'm sorry to point it out, but X-Rays and Gamma Rays are magnetically neutral EM radiation. They won't be deflected by magnetic fields. The stuff that causes the auroras are Charged! Particles! in the solar wind.
Best way to shield yourself from X-Rays and Gamma-Rays is to get something massive or dense between yourself and the radiation source.
matapampamuphoff on July 18th, 2018 11:31 pm (UTC)
Re: Scientific nitpicking
I suppose I should make them a little more clued in, since they work in space. Perhaps it would be better to have the bulk of one of the other stars directly between them and the supernova.

Edited at 2018-07-18 11:33 pm (UTC)
(Anonymous) on July 19th, 2018 01:01 am (UTC)
astrophysics
I like the premise of scientists and miners beavering away on top of an active volcano (in space...), but the astrophysics seems a little squiggly.

In a binary star system, A is the brighter star and B the dimmer. In a close binary the two stars affect each other's evolution. https://www.space.com/22509-binary-stars.html You can get a Type I supernova by mass accretion from a larger companion onto a white dwarf. https://www.astronomynotes.com/evolutn/s11.htm

But that is not the same thing as a core collapse supernova, which is what appears to happen in the story. https://en.wikipedia.org/wiki/Type_II_supernova Core collapse causes a huge neutrino pulse of about 1046 joule (1053 erg) over about ten seconds. “Through a process that is not clearly understood” about 1% of this pulse powers the expanding shock wave which blows up the star.

I had trouble finding a description of what a Type II supernova would look like from close up, but https://www.quora.com/How-fast-does-a-stars-mass-move-through-space-right-after-a-supernova-explosion seems reasonably informative. The neutrino flux is so intense that you would want to be at least 4 light years away in order not to die from neutrino radiation poisoning (eek). The shock wave moves at only about 5% light speed so it won't even reach the surface of the star for about a day.

The story locale seems to be somewhat inspired by Alpha Crucis A and B although those stars are at least 430 AU (60 light hours) apart and Crucis B is currently on the main sequence, so it's still good for millions of years.

-TomR
matapampamuphoff on July 19th, 2018 01:08 am (UTC)
Re: astrophysics
I don't recall when I did the research, and reading it myself I couldn't tell if the A component was a single or close double. I'll have to re-research, if i ever go anywhere with this one.
matapampamuphoff on July 19th, 2018 01:25 am (UTC)
Re: astrophysics
Quick and dirty recheck, Alpha 1 is a close double, the larger of which is big enough for an iron core collapse. Alpha 2 is 430+AU distant and likewise a strong B or O with the potential for an iron core collapse causing a Faint II-P supernova.

Going to have to update my terminology, but these look like good candidates to study the phenomena.
(Anonymous) on July 19th, 2018 07:41 pm (UTC)
Re: astrophysics
Hmm. https://what-if.xkcd.com/73/ discusses supernova neutrino radiation poisoning and, citing an actual paper, gets a completely different result from the web site I related earlier. This new web site computes 2.3 AU (0.32 light hour) as the distance at which you would get a 5 sievert radiation dose from a core collapse neutrino burst.

With a single dose of 5 sievert half the population dies within a month (LD50). A dose of 1 sievert makes you quite sick and gives about 5% elevated chance of eventually developing fatal cancer. Compare this to a full body CAT scan, which is a dose of 10 to 30 millisievert.

Since a red supergiant has a radius of about 1 light hour, 2.3 AU would be within the star itself. This is not a likely place from which to observe an incipient supernova. It seems more plausible that the observatory would be 20 times further out, at 46 AU (6 light hour), about the distance of Pluto from the sun. That would cut the neutrino radiation dose by a factor of 400 to 13 millisievert, about the same as a full body CAT scan and thus clearly survivable. Even only 10 times further out, at 23 AU (a little further than Uranus from the sun), would give a dose of 50 millisiervert, which is below the known threshold of increased cancer risk.

So based on this new web site, surviving the neutrino blast looks plausible.

-TomR
(Anonymous) on July 19th, 2018 08:22 pm (UTC)
Re: astrophysics
Oh, I see more info in the story. The scientists think that the shock wave will travel at 0.23 c and reach them in a little over 9 days => hence they are a little over 2.07 light days (358 AU) from the supernova.

Separation of Alpha Crucis A from B is at least 430 AU and "They were only a little further from the A component". Alpha Crucis A is a double with 1 AU separation and "double spark of the distant stellar pair".

Hmm. Human eye angular resolution is about 0.02 degrees. At 430 AU that works out to 0.129 AU. Okay.

Yep, it matches up with the Alpha Crucis B locale all right.

-TomR
matapampamuphoff on July 19th, 2018 08:35 pm (UTC)
Re: astrophysics
Oh good. I hate it when I completely screw up research. Not researching "because I knew" is another irritant.
(Anonymous) on July 20th, 2018 05:58 pm (UTC)
Re: astrophysics
It seems in the story that visible radiation effects commence immediately upon the neutrino blast. After reading up as much as I can stand on type II supernovas (you can find everything on the web, including recordings of physics seminars on supernovas), that does not seem to conform to our current understanding.

As I understand the current theory, the core collapse causes gravitational waves, a ten-second neutrino flash, and an x-ray and gamma ray flash. These can all be observed because the star is relatively transparent to them. But the star is essentially opaque to visible and UV photons, so we don't see much of them until the shock wave reaches the surface of the star, which takes hours (about a day).

When the shock wave gets to the surface of the star, there is a 10 to 20 minute UV flash (of which we actually have a few lucky pictures) followed by rapidly growing visible luminosity as the star swells at about 10,000 km/sec radially (some measurements say 0.05 c). As the shock wave has ionized all the outer-layer hydrogen, which makes it opaque to photons, all you can actually see is the swelling surface until its temperature drops low enough to allow recombination, which takes days.

The luminosity peaks in 10 to 20 days and then starts to fall off linearly (on a log scale) if it is a type II-L. A type II-P drops slightly from the peak but then plateaus for a month or so powered by radioactive decay before falling off.

Of course, science in the story is allowed to be different from our current science. But it seems suspicious to me that the story scientists think that the shock wave will expand at 0.23 c. In our current theory, that is the speed reached by the outer part of the core as the core collapses into degenerate neutronium.

-TomR
matapampamuphoff on July 20th, 2018 08:11 pm (UTC)
Re: astrophysics
What! You mean things have changed since I wrote it!

A quick check of my backups has it present in 2009, so it's at least eight years old.
matapampamuphoff on July 21st, 2018 01:33 am (UTC)
Re: astrophysics
This is always a problem in SF. The science gets outdated. You do the best you can and kick it out the door. If I ever finished this, I'll have to update the supernova. Fortunately the magic handwavium of wormholes will (probably) hold up longer.