Some more notes here on this interesting exoplanet report. Another report was published last month, A cosmic tango: This distant planet's strange orbit points to a violent and chaotic past,
https://phys.org/news/2022-07-cosmic-tango-distant-planet-strange.html
My observation. Presently HD 83443 b semi-major axis = 0.0406 au, e = 0.012. HD 83443c semi-major axis = 8.0 au, e = 0.76. Currently the semi-major axis is some 197x larger for HD 83443 c than HD 83443 b. Given the properties for HD 83443 c with e = 0.76, the periastron ~ 1.92 au, apoastron (apastron) ~ 14 au. The initial birthplace for both exoplanets in HD 83443 system and effect(s) of a near miss or near collision requires some serious modeling to account for the two-exoplanet system using migrating planets in a large disc to explain their present orbits. Using properties shown for HD 83443 b, I calculate P = 3.1491E+00 days, listed P = 2.985628-day orbital period. In 1 Gyr this exoplanet could complete 1.1599E+11 revolutions or about 116 billion if in a stable orbit. No disc is reported at HD 83443 system with age published as 2.94 Gyr old. Using the 1 solar mass MMSN and applying to the host star 0.9 solar mass size, a postulated protoplanetary disc may contain 2.996635E+03 or nearly 3,000 earth masses, total gas and dust. As the phys.org report stated about this two-exoplanet system, “The newly-discovered world, HD83443c, might be the reason its sibling ended up on its current hellish orbit."
I note some unobserved objects (UOs) in the report.
1. Primordial protoplanetary disc around HD 83443
2. The two exoplanets initial birth locations in the disc
3. Planet-planet near miss when the system was young (e.g., Planet–
planet scattering in the upsilon Andromedae system,
https://www.nature.com/articles/nature03427,
14-April-2005
4. Migrations of the two planets to their present orbits.