239 Adrastea

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

Johann Palisa

Discovery date

18 August 1884

Pronunciation

/ æ d r ə ˈ s t iː ə /

Named after

Adrasteia

Alternative designations

A884 QA, 1915 TD, 1955 MK 1 , 1956 UJ

Minor planet category

Main belt

Observation arc

131.66 yr (48,087 d)

Aphelion

3.66279 AU (547.946 Gm )

Perihelion

2.2695 AU (339.51 Gm)

Semi major axis

2.96616 AU (443.731 Gm)

Orbital period sidereal

5.11 yr (1,865.9 d)

Average orbital speed

17.25 km/s

Mean anomaly

Wikidata facts

Instance of

asteroid

Named after

Adrasteia

Followed by

Q148915

Follows

238 Hypatia

Parent body

Sun

Minor-planet group

asteroid belt

Diameter

+37.609

Orbital period

+1865.423378002167