The Closest Past Flyby of a Known Star to the Solar System: HD 7977, UCAC4 237-008148 or WISE J072003.20-084651.2?
Abstract
It is argued that the closest past flyby of a known star to the solar system was that of Scholz's star (WISE J072003.20-084651.2). Here, we show that the distribution of distances of closest approach of this star has a median value of 0.330 pc with a 90% probability of coming within 0.317-0.345 pc of the Sun; the associated time of perihelion passage is determined to be between 78.6-81.1 kyr ago with 90% confidence, with a most likely value of 79.9 kyr. Using Gaia DR3 data and the latest planetary ephemerides, we found that UCAC4 237-008148 (RUWE = 0.927) approached even closer with a median perihelion distance of 0.259 pc and a 90% confidence interval of 0.249-0.269 pc, 1.158 Myr ago. HD 7977 might have passed 0.15 pc from the Sun 2.77 Myr ago, but it has RUWE = 2.015.
- Publication:
-
Research Notes of the American Astronomical Society
- Pub Date:
- July 2022
- DOI:
- 10.3847/2515-5172/ac842b
- Bibcode:
- 2022RNAAS...6..152D
- Keywords:
-
- Stellar kinematics;
- Solar system;
- 1608;
- 1528