A bright multiple star system with an extinct biosphere discovered on one planet, also site of early star-lifting experiments.
Ishtar (Regulus)
Image from person43
Ishtar, a Gaian world orbiting Regulus B, now successfully terraformed

Regulus -data panel

Star NamesRegulus, α Leonis, 32 Leonis, Cor Leonis, Lion's Heart, Kalb al Asad, HIP49669
Distance from Sol79 light years
RA10h 08m 12.8
Dec11. 59′ 48
Regulus system
Image from Steve Bowers
The four stars of the Regulus system as they existed when the colonists first arrived. Regulus A is rotating rapidly, and was one of the first stars to be modified by starlifting technology.

Quadruple star system

StarsRegulus A: oblate B8 blue-white subgiant
Mass x 3.8 Sol
Luminosity 300 x Sol (150 x Sol in visible light)
Currently undergoing starlifting.
Regulus E white dwarf orbiting Regulus A at 0.35 AU
(this star lost a lot of mass to Regulus A during the last stages of its evolution)
Regulus B K2V orange dwarf orbiting Regulus A at 4200 AU
Mass 0.8 x Sol
Luminosity 0.5 x Sol
Regulus C M4V red dwarf in a binary pair with Regulus B, with a separation of 97 AU.
Mass 0.3 x Sol
Luminosity 0.02 x Sol
Microjovian -Regulus red dwarf
Image from person43
Nergal, a subjovian world orbiting Regulus C


Planets orbiting Regulus A10084+1158a (Metasoft designation; this planet was originally given the name Dumuzid)
Type Areanxeric (a desert world, formerly a Venus-like planet before Regulus E boiled most of its atmosphere away during its red giant phase)
Diameter 12101km
Mass 0.94 x Earth
Surface gravity 0.99 x Earth
Semi-major axis 3.81 AU
Orbital period 3.81 standard years
10084+1158b (Metasoft designation; this planet was originally given the name Ninlil)
Type Ferrinian Type (a small, iron-rich world)
Diameter 5137 km
Mass 0.059 x Earth
Surface gravity 0.36 x Earth
Semi-major axis 6.08 AU
Orbital period 7.69 standard years
The Lion's Mane, an asteroid belt between 7 and 15 AU
10084+1158c (Metasoft designation; this planet was originally given the name Adapa)
Type Selenian (a small dry world)
Diameter 4085 km
Mass 0.028 x Earth
Surface gravity 0.27 x Earth
Semi-major axis 26.3 AU
Orbital period 69 standard years
10084+1158d (Metasoft designation; this planet was originally given the name Uanna)
Type EuJovian Type (a gas giant in 5/4 harmonic resonance with 10084+1158d)
Diameter 120850 km
Mass 129.7 x Earth
Semi-major axis 30.6 AU
Orbital period 86 standard years
10084+1158e (Metasoft designation; this planet was originally given the name Neti)
Type Skolian/Ikarian (a gas giant with an extreme axial tilt and high eccentricity)
Diameter 101090 km
Mass 80.9 x Earth
Semi-major axis 106.84 AU
Eccentricity 0.518
Periastron 51.45 AU
Orbital period 566 standard years
Planets orbiting Regulus BNanshe:
Type SuperCytherian (a super-Venus type world)
Diameter 19376 km
Mass 4.22 x Earth
Surface Gravity 1.84 x Earth
Semi-major axis 0.13 AU
Orbital period 0.052 standard years
Type Gaian (a hot Earth-like type world, now terraformed)
Diameter 11010 km
Mass 0.68 x Earth
Surface Gravity 0.92 x Earth
Semi-major axis 0.13 AU
Orbital period 0.27 standard years
Moons 2;
Nanna 630 km in diameter
Suen 2480 km in diameter
Type MicroJovian Type (a small gas giant)
Diameter 27010 km
Mass 11.8 x Earth
Semi-major axis 1.87 AU
Orbital period 2.85 standard years
Kuiper belt between 3 AU and 30 AU, near the limit of stable orbits around this star
Planets orbiting Regulus CNabu:
Type Hermian (a Mercury-like world)
Diameter 5536 km
Mass 0.073 x Earth
Surface Gravity 0.39 x Earth
Semi-major axis 0.0147 AU
Orbital period 0.0032 standard years
Type SubJovian Type (a small gas giant)
Diameter 30009 km
Mass 27.4 x Earth
Semi-major axis 0.032 AU
Orbital period 0.0104 standard years
Type Arean (a Mars-like world, with evidence of an extinct biosphere. This world has a 2:3 spin-orbit resonance)
Diameter 7190 km
Mass 0.16 x Earth
Surface Gravity 0.5 x Earth
Semi-major axis 0.073 AU
Orbital period 0.036 standard years
Type MicroJovian Type (a small ringed gas giant)
Diameter 29190 km
Mass 19.1 x Earth
Semi-major axis 0.22 AU
Orbital period 0.188 standard years
Type EuJovian Type.
Diameter 140990 km
Mass 434.2 x Earth
Semi-major axis 0.91 AU
Orbital period 1.58 standard years

Kuiper belt between 1.4 AU and 20 AU, near the limit of stable orbits around this star
One of the brightest stars in the Inner Sphere, the Regulus star system consists of a B-type subgiant star with a white dwarf in a relatively close orbit, and an orange dwarf and a red dwarf orbiting each other at thousands of AU from the first pair. Regulus A is unusually bright and massive for a star of its age (around a billion years), since it absorbed a lot of mass from Regulus E when that star left the main sequence.

Each pair of stars was colonized by different group. The primary pair was colonized by vecs (from 39 Leonis) in 2231 AT. The orange dwarf of the outer pair was colonized by a coalition of lazurogened members of the Homo genus, including Erectus, Heidelbergensis, and Neanderthals (from Xi Ursae Majoris) a few years later. The fleets detected each other and were in communication en route. The humans and vecs have had mostly neutral relations over the millennia, but a few minor conflicts and even full-scale wars have occurred on occasion.

Microjovian -Regulus
Image from person43
Anu, a microjovian orbiting Regulus B, and one of its colonised moons.
The humans settled on Ishtar, the second planet of the orange dwarf which was a good terraformation candidate. They also occupied the moons of Anu, its Microjovian third planet.

An extinct biosphere is discovered

Enlil - Regulus
Image from person43
Enlil is a Arean world with xenofossils that indicate the former presence of a now-extinct biosphere
In 2259 a vec probe exploring the red dwarf's system detected signs of ancient water on Enlil, the Arean third planet, and in 2262 it was determined that the planet once possessed a biosphere of simple pre-Prokaryote level organisms, which likely went extinct about 15 million years earlier.
The apparent cause of the biosphere's collapse was the planet's small mass which allowed the atmosphere to slowly leak away, and then at least one major flare from the planet's sun which magnified the damage.

Terraformation of Ishtar

Ishtar - Regulus
Image from person43
The terraformation of Ishtar was completed in 2757 AT
In 2372 the terraformation of Ishtar began, which would be completed 385 years later. In the modern era the planet's surface is divided into low-tech reserves, modern settlements that are inhabited only by the archaic humans, and cosmopolitan settlements inhabited by beings from the rest of the Terragen Sphere.

Starlifting of Regulus A

Regulus- star-lifting
Image from Steve Bowers
The star-lifting rig around Regulus A is powered by statite power collection caps supported by light pressure over the north and south poles; these collectors send energy to the equatorial rings, which scoop mass from the mid-regions and magnetically accelerate it into orbit
A star-lifting operation began in the 2620s on the system's B-type primary (which was initially difficult because of its significant luminosity). Copying them, the archaic-human civilization began mining star B shortly thereafter. In 3086, since the system's main star was beginning to leave the main sequence, the vecs decided to begin an operation to remove mass from this star and extend its main sequence lifetime. This would be one of the first star lifting operations in the Terragen sphere. Since the star was already rotating in only 15.9 hours, it would begin shedding mass if accelerated to 15.35 hours. So a large ring apparatus was built and used to accelerate the star's spin. The two inner planets were dismantled or heavily mined. Mass from the star has been used to create computronium nodes, habitats of several different kinds, and to build and propel spacecraft and starships.

During the Version War the vecs in this system were nominally aligned with the Metasoft side, but they avoided the conflict by adopting an tacit stance of neutrality.

The starlifting operations continued unchecked during this period, and continued until the 6200s, removing a total of 0.4 solar masses from the star. At this point a archailect aligned with the Sophic League took control of the structure. The starlifting op has continued, but more intermittently and at a much lower rate.

The hominid cultures on Ishtar are also aligned with the Sophic League, and the local archailect is known to take a close interest in the welfare of these cultures. Some of the local cultures on this world utilise a typical technology level for Sephirotic modosophont-level cultures, while others are at Lotech or Prim level. Some of the largest and most sophisticated cities on this world have been designed and built by the Neanderthals, who have developed their own idiosyncratic forms of literature, music, architecture and art that are significantly different to those developed by Homo sapiens and their descendants.
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Development Notes
Text by person43
additional material by Steve Bowers
Initially published on 06 June 2019.