Picture of the Day · NASA
PK 164 +31.1: The Headphone Nebula
2026-05-27
What is a pair of headphones doing in the sky? Today’s image features the Headphone Nebula, also known as PK 164 +31.1 or Jones-Emberson 1. This planetary nebula, the remnant of a dying Sun-like star, faintly occupies an angular region of the Lynx constellation about 1/5th the diameter of the full moon. The red and blue-ish green colors trace hydrogen and oxygen atoms, respectively, that have been excited and ionized by the nebula's central white dwarf. The headphone shape, where two lobes of hydrogen puncture the inner region of oxygen, adds this object to a long list of oddly shaped nebulae. The morphology of such strange nebulae hint at the presence of a stellar or planetary companion, which can stir the material flowing out from the dying star. You can listen to Hubble and JWST sonifications of planetary nebulae through your very own headphones!
via NASA APOD
Key facts
- Discovered by
- James C. Watson
- Discovery site
- Angell Hall Observatory
- Discovery date
- 13 June 1873
- Pronunciation
- / ˈ iː θ r ə /
- Named after
- Aethra
- Alternative designations
Article
132 Aethra is a metallic asteroid and Mars-crosser on an eccentric orbit from the asteroid belt. It was discovered by James Craig Watson on 13 June 1873 at Angell Hall Observatory in Ann Arbor, Michigan. It is the first Mars-crossing asteroid to be identified. It subsequently became a lost asteroid, and was only rediscovered in December 1922. It is named after Aethra, the mother of Theseus in Greek mythology.
Aethra measures approximately 43–44 kilometers in diameter and has a rotation period slightly longer than five hours. It is the largest and brightest of the Mars-crossers and is classified as an M-type asteroid under the Tholen classification scheme. Its surface is relatively reflective and is likely composed of various silicate, hydroxide, and iron-bearing minerals.