Astronomy & Space

APOD: 2026 October 21 – New Ghosts Revealed in Cassiopeia

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Astronomers used 100 hours of observation with a special oxygen filter to reveal three previously unknown nebulas in the Cassiopeia constellation, alongside the known IC 59 and IC 63 nebulas near the multi-star system γ Cassiopeia. The newly discovered objects appear blue due to ionized oxygen, with Object 3 potentially representing a bow shock from γ Cassiopeia moving through interstellar material, while Object 1 may be a planetary nebula if a central white dwarf is confirmed. The hydrogen gas in IC 59 and IC 63 glows red from energetic light exposure, while their dust reflects blue-ish white starlight.


This discovery expands our understanding of nebular structures and stellar interactions in our galaxy, particularly how fast-moving star systems can ionize and compress surrounding interstellar material. The findings may help astronomers identify similar bow shock phenomena and planetary nebulas in other regions of space.


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The sky is speckled with stars. Bright tufts of emission nebulae trace across the image's equator. Arcs and smudges of ionized oxygen emission also included.The sky is speckled with stars. Bright tufts of emission nebulae trace across the image's equator. Arcs and smudges of ionized oxygen emission also included. The three new objects visible in oxygen are labeled.

New Ghosts Revealed in Cassiopeia

Explanation: Jinkies, look at all those ghosts! It took 100 hours of observation and a special oxygen filter for today’s image to capture three faint nebulas hidden in the Cassiopeia constellation. IC 59 and IC 63, the original Ghosts of Cassiopeia, haunt the region near multi-star system γ Cassiopeia. Energetic light from γ Cassiopeia causes the hydrogen gas in IC 59 and 63 to glow red. Their dust reflects and scatters some blue-ish white starlight. Newly discovered Objects 1, 2, and 3 appear as blue phantoms, revealing the presence of ionized oxygen. But ionized by what? Like at the bow of a speeding boat, γ Cassiopeia may be piling up material as the system moves through interstellar gas and dust. It follows that Object 3 may be the compressed and heated oxygen of that bow shock. Object 1 could be a planetary nebula if a central white dwarf is identified. The origins of these astronomical apparitions remain a mystery to be solved.

Tomorrow’s picture: it’s not easy being green

Date: October 21, 2026
Credit & Copyright: Louis Leroux-Géré, Thibault Rouillée, Vincent Martin, Cédric de Decker (Starfront Observatories)
Authors & editors: Keighley Rockcliffe, Robert Nemiroff, Jerry Bonnell, Cecilia Chirenti
A service of: ASD at NASA / GSFC,
NASA Science Activation & Michigan Tech. U.

Source: APOD: 2026 October 21 – New Ghosts Revealed in Cassiopeia