Herbig-Haro

"Out of here!" he bawled the instant the airlock doors were sealed behind him. "They have more things to worry about now than us."

Praise of Folly outran the missiles that came streaking after her, sped toward free space. Chang whooped and punched for champagne.

His glee proved short-lived, for the Zanat spacecraft in orbital patrol were more alert than the distracted planetary forces. The radio crackled with challenges, which he ignored. Radar and contragrav detector warned of ship-to-ship missiles, faster and more deadly than ground-based weapons.

"Take 'em out," Chiang said, adding quickly, "Chemical warheads only. One day soon we'll have to deal with these people, and I don't want to be remembered for screwing up a whole planet with an electromagnetic pulse from our atomics."

But he did not want to be shot out of the sky, either, and did not tell Praise of Folly to degrade its countermissiles' performance. With better sensors and stronger contragravs, they easily destroyed the attackers. Small puffs of red and gold flame blossomed astern.

Far sooner than most pilots would have dared, he went over to hyperdrive. He was so exhilarated that the surge was over before he remembered he should have been sick. He gu

"Just have to run them into the ground, then," he muttered. But the bogey refused to disappear. After awhile, another crawled onto the edge of the screen, and then two more. All were prominent echoes, warcraft for certain.

He tried to console himself with the truism fallen back on by every captain in trouble since the days of ships on Terran seas: a stern chase is a long chase. But when he looked at the detectors, he saw that it would not be long enough.

It was several days later, ship's time, when he and the computer finished commiserating with each other over his poor choice of drinking establishments. By then his lead, almost a light-year when he set out, had melted to hardly more than half an AU. The Zanat ships were maneuvering into englobement formation: if they surrounded him and touched his drive field with all theirs at once, they and he would be thrown into normal space together, with all the odds in their favor in the ensuing slugging match.

"I'll have to go sublight myself first," he decided unwillingly: the last resort of an outmatched pilot.

"Maybe," he added without much belief, "they'll lose me." If the ploy would ever work. the Nebula was the place for it. Gas and dust could play merry hell with gadgetry.

Any particularly thick patches close by?" he asked hopefully.

The computer was silent for nearly a minute while it searched its memory and added corrections for several centuries of proper motion. At last it said, "As it happens, yes. We're near a Herbig-Haro object."

"New one on me," the scout pilot admitted. "What is it?"

"A luminous nebula with a denser center that—"

"Say no more that's exactly what we need. They'll have to have their engines linked to their detectors and drop out of hyperdrive the moment we do, or else overshoot and lose me for good. FTL, half an AU is nothing. Set our course so that when we and they break out, they'll be smack in the middle of that denser center." Chang let his optimism run wild. "One of them might even emerge coincident with a rock, and lower the odds. Can we fight three?"

"Not with our store of missiles depleted as it is," the computer answered at once. The scout pilot sighed. Praise of Folly went on. "Reconsider your plan. Herbig-Haro objects are—" Chang was not about to be balked by mechanical mutiny. "Execute, and no chatter," he said harshly. "Override command."

The silence that fell had a reproachful quality to it. Praise of Folly changed course. Like hounds after a rabbit, the Zanat ships followed.

Chang's nails bit into his palms. His lead was a bare half-AU now, hardly seventy-five million kilometers. If this Herbig-Haro whatsit didn't show up soon, the Zanat would force him out of hyperdrive and fight on their own terms.

Praise of Folly gave a sudden, sickening lurch. Her normal-space instruments came back to life—and at that same instant, every alarm in the ship went off. Red lights flared, claxons hooted, bells jangled, a commotion to wake the dead.

Chang did not even notice it. His mouth hanging open, he was staring in disbelief at the view screens. "What the bleeding hell is a star doing there'?" he said in something like a whispered scream. A star it was, a crimson monster. Praise of Folly could hardly have been more than fifteen million kilometers from the edge of its chromosphere. Had Chang been on the surface of a planet at that distance, its great orb would have stretched across almost two-thirds of the sky. He could peer deep through the tenuous gases of its outer atmosphere, could gauge the temperature of the swirling currents by their colors: here a ruby so deep the eye almost refused to register it, there a coruscating up rush of brighter, molten red. It was like looking down on a stormy ocean of flaming wine. The sight held Chung fascinated until he absently wiped his hand across his forehead. It came away slick with sweat, As the alarms could not, that reminded him where he was. Another few seconds and he would cook, no matter how well-shielded the ship was. His finger jabbed the hyperdrive switch. The abused engines groaned, but the wrench that sent Praise of Folly FTL was the most welcome thing he had ever felt. The clamor of alarms faded away. Nothing whatever showed on the hyperdrive detector. Chang shivered. "One thing's certain, they never knew what hit'em." Moths in a blowtorch—

He shivered again as reaction set in. That could have been him emerging in the center of a star . . . a star the computer had not known about. "You almost fried out both!" he howled. There was no reply. He remembered his last command. "Override lifted," he said. "I want to hear what you have to say for yourself. Why did you think you were diving into a nebula instead of a star?"

"That should be obvious even to you," the computer said, testy as usual after an override. "When my navigation data was compiled, that star did not exist."

"Tell me another one," Chang snorted, "one I'll believe."

"Your ignorance is not my problem, except that it almost destroyed Praise of Folly, and you with it. You would not listen to my warning. As long ago as the end of the second century pre-Confederacy, astronomers knew that a Herbig-Haro object was the precursor to a star."

"You really mean it," the scout pilot said in wonder.

"Yes, I really do," The computer seemed determined to get its own back. "Why do you think a Herbig-Haro object is luminous? The energy emitted by the slowly condensing cloud in the center ionizes the gas around it and makes it glow.

"But when gravitational contraction brings the cloud down to about the size of Sol's system—say, eighty AU's across—something new happens. Some of the energy inside stops going into heating the gas of the cloud and starts breaking up hydrogen molecules and such in the center, things are begi

"And when that energy gets diverted, there isn't enough gas pressure left to support the outside of the cloud any more. It falls in on itself over the next half a standard year or so, until it shrinks to a diameter of about eight-tenths of an AU. Then the heat and pressure generated by the collapse restore equilibrium and the new star becomes visible, with a surface temperature of 4,000° K or so."