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Astronomy Picture of the Day - The Images not Posted during the Government Shutdown - 50 Light-years to 51 Pegasi
NASA ^ | 10 Oct, 2025 | Image Credit & Copyright: José Rodrigues

Posted on 11/25/2025 9:47:00 AM PST by MtnClimber

Explanation: It's only 50 light-years to 51 Pegasi. That star's position is indicated in this snapshot from August 2025, taken on a night with mostly brighter stars visible above the dome at Observatoire de Haute-Provence in France. Thirty years ago, in October of 1995, astronomers Michel Mayor and Didier Queloz announced a profound discovery made at the observatory. Using a precise spectrograph, they had detected a planet orbiting 51 Peg, the first known exoplanet orbiting a sun-like star. Mayor and Queloz had used the spectrograph to measure changes in the star's radial velocity, a regular wobble caused by the gravitational tug of the orbiting planet. Designated 51 Pegasi b, the planet was determined to have a mass at least half of Jupiter's mass and an orbital period of 4.2 days. That made the exoplanet much closer to its parent star than Mercury is to the Sun. Their discovery was quickly confirmed and Mayor and Queloz were ultimately awarded the Nobel Prize in physics in 2019. Now recognized as the prototype for the class of exoplanets fondly known as hot Jupiters, 51 Pegasi b was formally named Dimidium, Latin for half, in 2015. Since its discovery 30 years ago, over 6,000 exoplanets have been found.


TOPICS: Astronomy; Science
KEYWORDS: apod; nasa

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1 posted on 11/25/2025 9:47:00 AM PST by MtnClimber
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To: MtnClimber

2 posted on 11/25/2025 9:47:31 AM PST by MtnClimber (For photos of scenery, wildlife and climbing, click on my screen name for my FR home page.)
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To: 21stCenturion; 21twelve; 4everontheRight; A Navy Vet; A_perfect_lady; abb; AFB-XYZ; AFPhys; ...
Pinging the APOD list

🪐 🌟 🌌 🍔

3 posted on 11/25/2025 9:48:13 AM PST by MtnClimber (For photos of scenery, wildlife and climbing, click on my screen name for my FR home page.)
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To: MtnClimber

4 posted on 11/25/2025 10:09:18 AM PST by Diogenesis (Si vis pacem, para bellum)
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To: Diogenesis

A 4 day orbital period…. that’s screaming fast…..😮


5 posted on 11/25/2025 10:43:57 AM PST by telescope115 (Ad Astra, Ad Deum…)
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To: MtnClimber
Oh.

I thought they said 50 Light-years to Pelosi...

Nevermind.

6 posted on 11/25/2025 12:55:14 PM PST by Savage Beast (When the student is ready, the teacher appears.)
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