Unfortunately, I edited this page instead of duplicating it to make the Round 3 bracket. That being said, I deleted half of the content and hit save before I realized my mistake, making it unable to be restored. I’ve recovered as much information as I could from my thread on Twitter, but it isn’t as complete as the original. *facepalm*

Round 2 was about “What’s it made of?” and we found that most of our nebulae in the bracket are HII regions—regions of ionized atomic hydrogen gas (H+), a marker of recent star formation. Across the different nebulae, there was a variety of the types of objects within, with star clusters, white dwarfs, or dust helping to give the nebulae their visible characteristics.

The division champs are:

• Birds: Eagle (the Eagle Nebula and the Parrot’s Head Nebula tied, but this face-off ended on the birthday of an astrochemist and Eagle Nebula enthusiast, so happy birthday, Veronica! The Eagle Nebula is moving on!)

• Mammals: Cat’s Paw

• Sea creatures: Crab

• Bugs: Butterfly

Who will move on to the final round? Stay tuned to find out!

BIRDS: Eagle Nebula vs. Parrot’s Head Nebula

The Eagle Nebula, located in the constellation Serpens, is part of a diffuse emission nebula, or HII (“H-two”) region. An emission nebula is formed of partially ionized gas that emit light at various wavelengths. HII is ionized atomic hydrogen, or H⁺, and is present in regions where star formation has recently taken place. The Eagle Nebula is home an estimated 8100 stars that are mostly concentrated to the northwest of the famous “Pillars of Creation”. There are several other active star-forming regions of gas and dust located in the nebula as well.

The Parrot’s Head Nebula, often called the Seagull Nebula, is also an HII region that is actively forming stars in the constellation Monoceros. It is roughly circular and centered about the star HD 53367, but the emission region is often described to include the open clusters NGC 2335 and NGC 2343, along with neighboring dust clouds that help define its birdlike shape.

MAMMALS: Cat’s Paw Nebula vs. Otter Nebula

The Cat’s Paw Nebula is an emission nebula. It is an HII region thought to contain thousands of stars, but many of its stars are concealed by dust. The nebula’s glow is due to a host of hot young stars ten times as massive as the Sun; these stars burn very hot and very fast.

The Otter Nebula—-the unofficial name for NGC 604—is an HII region as well but one located outside the Milky Way in the Triangulum Galaxy. The nebula’s gas is ionized by a cluster of massive stars—around 200 O-type stars (the biggest, hottest, and bluest stars)—at its center.

SEA CREATURES: Crab Nebula vs. Turtle Nebula

The Crab Nebula is a supernova remnant in Taurus. The filaments in the nebula are remnants of the progenitor star, or the star that exploded at its center. These filaments are largely made up of ionized helium and hydrogen but also contain carbon, oxygen, nitrogen, iron, neon, and sulphur, all of which are made in the star.

The Turtle Nebula is a planetary nebula. This type of nebula is an expanding shell of ionized gas ejected from aging red giants. Despite the word “planetary” being in the name of this type of nebula, these nebulae have nothing to do with actual planets except that they are around stars, which most likely have at least one planet orbiting around them. The Turtle Nebula has hot gas jets streaming through an older shell of relatively cool gas. It spits out elements fused in the star’s core.

BUGS: Butterfly Nebula vs. Tarantula Nebula

The Butterfly Nebula is a bipolar planetary nebula extending out from a white dwarf. The bipolar outflows may have been caused by a dense disk of gas and dust. In the nebula, there is evidence of carbonates, crystalline water ice, and quartz.

The Tarantula Nebula is an HII region in the Large Magellenic Cloud. A bright star cluster at its center makes it so bright that if it were as close as the Orion Nebula (about 1300 lightyears away instead of 160,000 lightyears) it would cast visible shadows on the Earth!