New Nebula Uncovered by Amateur Astronomers near M31 Andromeda Galaxy

Orion Goodman

The [OIII] emission arc appears very bright in the images, but it is an extremely faint object that can only be adequately visualized by special subtraction techniques, because the signal is almost completely outshone by the light from M31's galactic halo in the unprocessed version.

AstroBin

The Andromeda Galaxy (M31), a well-known night sky object, has a new surprise to offer. A group of amateur astronomers recently discovered an emission nebula that spans half of the width of Andromeda. This previously unknown feature was discovered in images taken with an Oxygen-III (OIII) filter by French astronomer Yann Sainty, which he processed and analyzed with Marcel Drechsler and Xavier Strottner. It was dubbed the Strottner-Drechsler-Sainty Object 1 by the team.

The trio confirmed their discovery with the assistance of professional astronomers and other astrophotographers and published their findings in Research Notes of the AAS last month, along with a stunning image on the astrophotography archive and publishing site Astrobin.

This Andromeda observation began as a side project for the group, who had joined forces for another reason. Drechsler and Strottner kept a catalog of planetary nebulae and asked Sainty to photograph known and candidate objects. Sainty switched to studying the Andromeda Galaxy, using an OIII filter to reveal faint HII regions after traveling across France to find the darkest sites for his mobile observing setup.

Drechsler and Strottner were reviewing the OIII images when they noticed a faint nebulosity at the picture's edge that seemed to extend beyond the photo. Despite initial skepticism, Sainty collected 111 hours of exposure data, and the team grew increasingly confident in their discovery.

The team contacted professional astronomers, including Dartmouth College's Robert Fesen, who was initially skeptical. Fesen was persuaded after other astronomers confirmed the observations with their own telescopes.

Due to its faint and extended nature, previous OIII surveys of M31 on professional telescopes failed to detect the nebula. The MegaCam instrument on Mauna Kea's Canada-France-Hawaii Telescope (CFHT) has a field of view of 1°, which was insufficient to capture the full extent of the new object. Sainty used a narrowband Antlia filter with a bandwidth of 3 nm to isolate the OIII signal from background noise.

Find more on aquisition and ongoing research findings at: https://www.astrobin.com/1d8ivk/

This video produced by the StDr imaging team offers a comprehensive look into their findings: Strottner-Drechsler-Sainty Object