WD 0810−353

WD 1810−353 is a white dwarf of spectral type DAH^[2] with a very strong magnetic field, perhaps as strong as 30 MG.^[2] It has a mass of 0.63 M_☉ and an age of 2.7 billion years;^[2] its effective temperature is 6,093 K^[2] or 6,273 K.^[10] It is a dim object with an apparent magnitude of 14.5.^[2] Its motion perpendicular to the line of sight is considerable; it is consistently listed as a high proper motion star.^[11]

Both the minimum approach distance and the timing of the star's closest flyby depend strongly on the value of the radial velocity.^[12] Based on a radal velocity measurement from the Gaia DR3 database, WD 1810−353 is moving towards the Solar System at a velocity of −373.74±8.18 km/s, which together with its proper motions would imply it would approach the Solar System 29,000 years from now at a distance of around 0.15 parsecs (0.49 light-years, 31,000 AU), crossing well within the proposed boundaries of the Oort cloud. Considering the values from Gaia DR3, WD 1810−353 would traverse the Oort cloud, disturbing the population of comets there. Given its mass such an encounter like Gliese 710, would cause a negligible orbital change to the Pluto system and Neptune resonant object.^[3] However, this radial velocity was cast in doubt by a 2022 paper, as Gaia does not have the software necessary to accurately derive radial velocity measurements for white dwarfs from the raw data. In this study, an even more extreme radial velocity of −4,248±457 km/s was suggested, implying a closest approach in 2,600 years at a distance of 0.015 parsecs (0.049 ly; 3,100 AU). The extremely high radial velocity could suggest that WD 0810−353 formed after a Type Ia supernova.^[13] However, those values, and the flyby as a whole, were disproven in a 2023 study, which find WD 1810−353 is instead moving away from the Solar System, at a velocity of +83±140 km/s.^[6]