-74813b3e17f460286df-48b 20220606195330174 hyperscienceij@gmail.com:rcrl hyperscienceij@gmail.com WEB-FORM Hyperscience International Journals HIJ 28213300 06 2022 2 2 Plasma Physics Research Center, Science and Research Branch, Islamic Azad University, Tehran,1477893855, Iran Rezvan Saleh Ghafari https://orcid.org/0000-0003-0255-2282 Bijan Nikouravan https://orcid.org/0000-0003-4308-1632 Mohammad Kazem Salem https://orcid.org/0000-0001-5172-2204 HD 158259 (or HIP 85268) is one of the members of the main sequence in G0 group stars located approximately at 88 ‎light-‎years away in the constellation Draco, discussed with respect to the solar system. HD 158259 was discovered by the ‎SOPHIE ‎échelle spectrograph using the radial velocity method. This system includes five confirmed planets orbiting HD ‎‎158259, ‎together with one unconfirmed planet. The planets orbit in a near 2/3 (or 3:2) orbital resonance. Starting from the innermost ‎pairing, the period ratios are with the period ratios ‎‎1.5757, 1.5146, 1.5296, 1.5128, and 1.4482, respectively, starting from the ‎innermost pairing. Here we theoretically investigate the HD ‎‎158259 system for the Semi-major axis, planet's mass, star ‎luminosity, ‎ inner,‎‏ ‏ ‏center, outer, and ∆(HZ) habitable zone. We account for radial ‎velocity amplitude, planet density, and ‎Laplace’s resonance, theoretically. The existing possibility of the sixth and undetected ‎planet (HD 158259 g) was also ‎investigated. The orbital period and semi-major axis of this planet, computed with 0.047726 years (17.420 ‎days) and 0.135 ‎AU respectively, with 𝑅2 = 0.9964. The radial velocity amplitude of this new and undetected planet was ‎computed to be about ‎‎1.625 km/s. The mass of planets in terms of Solar, Jupiter, and Earth have shown direct direct proportional ‎relation with an ‎approximate increase in their semi-major axis. The lowest mass is closest to the star and the highest mass is farthest from the star. We ‎compare the habitability zone to that of NASA, Kopparapu et.al, and the original Kopparapu estimate. The application of the relative mean motion ration (RMMR) for resonance in the triads of successive planets showed that the mode of RMMR is ‎approximately ‎2/3 (or 3:2) orbital resonance, with the calculated period ratios shown above. we have also calculated the planetary ‎equilibrium temperature (PET) in terms of the size, temperature, Albedo and distance planet to its parent star.‎ 06 2022 46 56 10.55672/hij2022pp46-56 https://hscience.org/index.php/hij/article/view/24