| RD1 (0140+326 RD1) | |
| Epoch: | J2000 |
| Constellation Name: | Triangulum |
| Z: | 5.34 |
| Dist Ly: | around 12.5 billion light-years (light travel distance) ~26 billion light-years (present comoving distance) |
| Appmag V: | 26.1 |
| Names: | [DS98] 6C 0140+326 RD1 |
RD1 or 0140+326 RD1 is a distant galaxy, it once held the title of most distant galaxy known.[1] RD1 was discovered in March 1998, and is at z = 5.34,[2] and was the first object found to exceed redshift 5.[3] It bested the previous recordholders, a pair of galaxies at z=4.92 lensed by the galaxy cluster CL 1358+62 (CL 1358+62 G1 & CL 1358+62 G2). It was the most distant object known to mankind for a few months in 1998, until BR1202-0725 LAE was discovered at z = 5.64.
The "distance" of a far away galaxy depends on the chosen distance measurement. With a redshift of 5.34,[2] light from this galaxy is estimated to have taken around 12.5 billion years to reach us.[4] But since this galaxy is receding from Earth, the present comoving distance is estimated to be around 26 billion light-years.[4]