Andromeda
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Planet candidate — not confirmed

PA-99-N2b (candidate)

Open in Ouranos

In 1999 the POINT-AGAPE survey saw a star in Andromeda brighten and fade over months as something passed in front of it and bent its light — and the light curve has a small extra wiggle.

Measured

Distance
about 2.52 million light-years

How far, from the Sun

About 2.52 million light-years. To cross it:

  • Light2.52 million years
  • Voyager 1's speed44.8 billion years
  • Driving at 100 km/h27.2 trillion years

Voyager 1 at the speed it moved outward over the year to 2026-10-25 (JPL Horizons). Driving: nonstop, never refuelling.

Facts

  • PA-99-N2b is a candidate, not a confirmed planet: a single microlensing event in 1999, which can never be watched again.
  • A binary lens whose companion has about a hundredth of the primary's mass fits the wiggle (An et al. 2004).
  • If the lens is an ordinary half-solar-mass star in the disc, the companion is about 6 times Jupiter's mass — a planet (Ingrosso et al. 2009). If the lens is heavier, it could be a brown dwarf or a small star (An et al. 2004).

Where this comes from

  • Paulin-Henriksson et al. 2003 (A&A, doi:10.1051/0004-6361:20030519); An et al. 2004 (ApJ 601, 845); Ingrosso et al. 2009 (MNRAS 399, 219)

Every catalogue Ouranos draws is credited on the credits page.