S2 passes pericentre and its light is measurably redshifted
The star S2 made its closest approach to Sagittarius A*, passing within roughly 120 astronomical units at about two and a half per cent of the speed of light. Interferometric astrometry and spectroscopy with the GRAVITY instrument at Paranal detected the combined gravitational redshift and transverse Doppler shift predicted by general relativity, at a level clearly distinguishable from the Newtonian expectation. It was the first detection of that effect in the gravitational field of a supermassive black hole.
Observed — measured or witnessed, with the observation cited.
Subjects
- S2 - the star that measured the Galactic centre · celestial body · Galactic centre, constellation Sagittarius as seen from Earth · not located
- Sagittarius A* - the black hole at the centre of the Milky Way · celestial body · Galactic centre, constellation Sagittarius as seen from Earth · not located
- Paranal Observatory and the GRAVITY interferometer · research facility · Chile
- Time dilation near a horizon · phenomenon · not located
Evidence
Partly verified — Core facts are sourced; some optional detail is deliberately absent.
Detection of the gravitational redshift in the orbit of the star S2 near the Galactic centre massive black hole
Reports the combined gravitational and transverse Doppler shift in S2's spectrum at its 2018 pericentre passage, inconsistent with Newtonian prediction. V55 VERIFICATION BASIS: not consulted in session; no research tool was available. Volume and article number are from recall and must be checked.
Astronomy and Astrophysics (GRAVITY Collaboration) · 2018 · Partly verified
GRAVITY Collaboration, Astronomy and Astrophysics 615, L15 (2018)
Recorded on S2 - the star that measured the Galactic centre
- Oppenheimer and Snyder compute continued gravitational contraction
- A star is tracked through a complete close approach to the Galactic centre
- The Event Horizon Telescope observes M87* and Sagittarius A*
- S2 passes pericentre and its light is measurably redshifted
- The orbit of S2 is shown to precess as general relativity predicts
- The Nobel Prize in Physics recognises black holes twice over
- The black hole at the centre of our own galaxy is imaged
Related
Related because they share a subject in the Atlas — never because the text looks similar.
- The black hole at the centre of our own galaxy is imaged · 2022-05-12
- The Nobel Prize in Physics recognises black holes twice over · 2020-10-06
- The orbit of S2 is shown to precess as general relativity predicts · 2020
- The Event Horizon Telescope observes M87* and Sagittarius A* · 2017-04
- A star is tracked through a complete close approach to the Galactic centre · 2002
- Oppenheimer and Snyder compute continued gravitational contraction · 1939