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DMPP-3 Exoplanet System

Disintegrating rocky planets in a compact binary star system //

DMPP-3 is a real exoplanet system located 153 light years from Earth, consisting of two stars and possibly two planets, one of which is currently unconfirmed. The primary star, DMPP-3 A, is a high-end K0V orange dwarf with 0.9 solar masses, 0.861 solar radii and 51% of the Sun's luminosity. It is significantly older at 9.6 billion years in age. The secondary star, DMPP-3 B, is a much smaller red dwarf barely massive enough to fuse hydrogen, weighing in at just ~0.088 solar masses. It possesses an eccentric and inclined 507-day orbit around the primary, taking it from around 0.5 AU out to 2.0 AU.

DMPP-3 A was of interest to astronomers because its chromospheric emissions seemed to lie well below the expected values for solar-type stars. This was attributed to a shroud of gas absorbing the star’s light, possibly originating from a planet undergoing mass loss. The hypothesis was verified in 2019 with the discovery of DMPP-3 A b—a super-Earth on a short 6.67-day orbit around the primary star. A rocky planet at this distance would be heated so intensely that its surface is vaporised and carried off in the thermal wind. In 2023, an even closer 2.26-day signal was detected from a potential second planet DMPP-3 A c. While yet to be confirmed, this candidate would be hotter and lower in mass than its neighbour and is therefore the more likely source of the circumstellar gas shroud.

The DMPP-3 system is unique due to its unusually compact architecture. It is the tightest known binary star system with an S-type planet (i.e. a planet orbiting one star of the binary). If it began in its current configuration, models predict that the influence of DMPP-3 B would have perturbed the protoplanetary disc around DMPP-3 A, hindering the formation of its current planet(s). Several scenarios have been proposed to explain this, from the objects initially orbiting both stars before being captured around just one, to DMPP-3 B coalescing elsewhere and then migrating inwards to its present position. Overall, DMPP-3 presents a challenge to our models but also offers an opportunity to further understand the mechanisms that sculpt exoplanets throughout our galaxy.

In this simulation, characteristics of the DMPP-3 system are replicated from literature wherever possible or inferred in cases of knowledge gaps:

• Assuming that DMPP-3 A b and DMPP-3 A c orbit on the same plane as the secondary star, they would possess 2.47 and 1.186 Earth masses respectively.
  
• I've designed DMPP-3 A b as a tidally-locked hot arid super-Terra. Its day side is covered with blotches of molten lakes that mould an ever-changing, inhospitable mesa. A thin atmosphere envelops the planet in a choking haze, with dark clouds of vaporised silicates condensing over the night side.
  
• I've designed DMPP 3 A c as a tidally-locked hot airless Ferria. Its surface is heavily cratered and heated much more intensely owing to its closer orbit, creating a global magma ocean spanning half the planet. The relentless bombardment by the stellar wind has stripped its atmosphere and a significant portion of its mass, leaving behind a composition dominated by its iron core.
  
• Two torus rings are used to represent the gas shroud and ablated planetary material around DMPP-3 A, with the inner ring denser to signify higher mass loss rates from DMPP-3 A c. I've reduced the number of particles to balance performance and aesthetics, but if it is still too intensive, feel free to clear them using Ctrl/Cmd + D. This will not affect the simulation.
  
• At its closest approach, DMPP-3 B provides an additional source of light for the planets. This leads to interesting periods of time when they could be entirely illuminated, albeit with a much dimmer twilight on the side facing the secondary star.

HD 42936, GC 7845, MSX LMC 1611, TYC 9172-203-1, AP J06062984-7230451, GEN# +1.00042936, NLTT 16149, UBV 6269, CD-72 312, HIC 28941, PLX 1441, WISEA J060629.84-723049.6, Ci 20 378, HIP 28941, PLX 1441.00, Gaia DR3 5266148569447305600, CPC 21.2 843, LTT 2468, PPM 369038, Gaia DR1 5266148565146677760, CPD-72 451, 2MASS J06062984-7230451, SAO 256269, Gaia DR2 5266148569447305600, DMPP-3, 2MASSI J0606298-723045, TIC 141765836

• Barnes, J.R., Haswell, C.A., Staab, D., Anglada-Escudé, G., Fossati, L., Doherty, J.P., Cooper, J., Jenkins, J.S., Díaz, M.R., Soto, M.G. and Rojas, P.A.P., 2019. An ablating super-Earth in an eccentric binary from the Dispersed Matter Planet Project. arXiv preprint arXiv:1912.10793.
  
• Haswell, C.A., Staab, D., Barnes, J.R., Anglada-Escudé, G., Fossati, L., Jenkins, J.S., Norton, A.J., Doherty, J.P. and Cooper, J., 2020. Dispersed Matter Planet Project discoveries of ablating planets orbiting nearby bright stars. Nature Astronomy, 4(4), pp.408-418.
  
• Stevenson, A.T., Haswell, C.A., Barnes, J.R., Barstow, J.K. and Ross, Z.O., 2023. DMPP-3: confirmation of short-period S-type planet (s) in a compact eccentric binary star system, and warnings about long-period RV planet detections. Monthly Notices of the Royal Astronomical Society, p.stad1441.