Andromeda's heart
M31* and the double nucleus
Andromeda's heart looks double: two peaks of starlight, P1 and P2, 0.49 arcseconds apart — about 1.8 parsecs (Lauer et al. 1993).
Measured
- Distance
- about 2.5 million light-years
How far, from the Sun
About 2.5 million light-years. To cross it:
- Light2.5 million years
- Voyager 1's speed44.4 billion years
- Driving at 100 km/h27 trillion years
Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.
Facts
- They are one thing: a disc of stars on lopsided, aligned orbits round the central black hole, crowding where they move slowest (Tremaine 1995's eccentric disc; Bender et al. 2005).
- Inside P2 is P3, a tiny cluster of young blue stars — probably born in a burst about 200 million years ago (Bender et al. 2005).
- P3's stars circle the black hole at about 1,700 km/s, 0.19 parsecs out, which weighs it at about 140 million Suns (Bender et al. 2005).
Where this comes from
- Lauer et al. 1993; Tremaine 1995; Lauer et al. 1998; Statler et al. 1999; Peng 2002; Bender et al. 2005
Every catalogue Ouranos draws is credited on the credits page.