The Sunflower Galaxy

The Sunflower Galaxy is a spiral galaxy in the Canes Venatici (the Hunting Dogs) Constellation. It is a bright galaxy in the northern sky that stretches about 100,000 light-years across, roughly the same size as the Milky Way. It has faint star-stream extensions caused by tidally-disrupted satellite galaxies. 

How Did Sunflower Galaxy Get Its Name?

This galaxy gets its name from its look-a-like, the sunflower. The bright yellow central core reminds observers of a sunflower’s middle portion or “head.”  The sunflower head’s florets also form two spirals, reinforcing the name. 

When was the Sunflower Galaxy Discovered?

French astronomer Pierre Méchain discovered the Sunflower Galaxy in 1779. It was the first of 24 celestial objects Méchain contributed to colleague Charles Messier’s catalog. It gained the designation Messier 63 in 1781. 

The Sunflower Galaxy Details

Here is an overview of the Sunflower Galaxy’s details. It is a dominant member of the M51 galaxy group. 

  • Object Names:
    • Messier 63
    • NGC 5055
    • Sunflower Galaxy
  • Galaxy Type: Flocculent Spiral
  • Constellation: Canes Venatici (the Hunting Dogs)
  • Distance From Earth: 37 million light-years
  • Apparent Magnitude: 9.3
  • Best Observation Time: May
sunflower galaxy
Image: NASA Hubble Space Telescope

Sunflower Galaxy’s Characteristics

Nature prefers spirals, and the Sunflower’s galactic arms reinforce this preference. The winding arms show streaks of cosmic dust lanes and shine with the brightness of young blue-white giant stars within the pink star-forming regions. As a result, astronomers think the Sunflower has periods of intense star creation.

How Big Is the Sunflower Galaxy?

The Sunflower Galaxy spans approximately 100,000 light-years, which is about the size of the Milky Way. It contains about 400 billion stars. The vast galaxy has a mass of about 140 billion times that of the Sun. In addition, the Sunflower may have a black hole about the size of 30 million Suns. 

How Bright is the Sunflower Galaxy?

With an apparent magnitude of 9.3, the Sunflower Galaxy appears only as a faint light patch in smaller telescopes. It’s not visible to the naked eye.

A Supernova on the Sunflower’s Arm

On May 24, 1979, a magnitude of 11.8 supernovae appeared on one of the Sunflower Galaxy’s arms. It reached peak light a couple of days later. SN 1971 I gained type I supernova status. 

What Type of Galaxy is the Sunflower?

M63 is a flocculent spiral galaxy. Instead of well-defined arms, as you find in the grand-design spiral Pinwheel Galaxy, the Sunflower only has two non-continuous arms. Each arm wraps 150° around the galaxy and extends from the center to 13,000 light-years.

Flocculent Spiral Galaxies and Star Formation

In the Hubble Space Telescope image below it looks like many arms twist and twirl around the galaxy’s yellow core. The newly formed stars in the arms shine with radiation, appearing blue in infrared imaging.

Astronomers have additional learning ahead about the role flocculent spiral galaxies play in star formation. Interstellar nurseries that birth new stars shape the universe. They provide the raw material for planetary systems and play pivotal roles in galaxy evolution. 

Hubble operators aim for a better understanding of star formation with flocculent spiral galaxies through their infrared images. 

spiral galaxy
Image Credit: NASA

Common Types of Galaxies

Although nature holds many variances, the three most common galaxy types are spiral, elliptical, and irregular.

Spiral Galaxy

Spiral galaxies have shapes like giant pinwheels with arms containing billions of stars. The gas and dust floating around the arms provide raw materials to create them. About 60% of all galaxies are spiral stellar nurseries. Their young stars shine more brightly than older stars since they burn hotter. 

Spirals have two main groups

  1. Standard: The arms that originate from the galaxy’s center.
  2. Barred spirals: A bar of stars passes through the central bulge, and the arms start at the bar’s end rather than from the galaxy’s center.

Examples: Pinwheel and Milky Way galaxies

Irregular Galaxy

Irregular galaxies get their names from having no definitive, common shapes. Their composition is the same as all other galaxies, with stars, gasses, and other raw materials, but they don’t contain much cosmic dust. 

They are among the smallest observed galaxies, and often, two or more collide to become spiral or elliptical galaxies. Irregulars are usually very bright, but they only account for about 20% of all galaxies. 

Example: Magellanic clouds and Sagittarius Dwarf Irregular Galaxy

Elliptical Galaxy

Elliptical galaxies are stretched-out circles or ellipses. While some are circular-shaped, others are elongated, looking long and flat. 

Since they have only small amounts of gas and dust, they are not stellar nurseries. Instead, their stars are generally old, so they aren’t as bright as spiral galaxies. Ellipticals are the biggest and most common galaxies. The largest ellipticals earn the name Giants because they span about 300,000 light-years. 

Example: NGC 4881 and M87

Viewing the Sunflower Galaxy

Find the Sunflower Galaxy in mid-Northern skies during the Springtime for the best viewing opportunities. It may appear as a faint hazy light patch with binoculars and smaller telescopes. 

Astrophotography provides the best results since it allows viewing night skies while capturing digital images. Once you digitally process the images with special software, the Sunflower Galaxy comes alive.

How to Locate the Sunflower Galaxy

During March, April, and May, around 10:00 pm local time, look to the northwest of the Ursa Major Constellation for the Sunflower Galaxy. It resides about two-thirds of the way from Alkaid Cor Caroli. That’s the bright star marking the Big Dipper‘s handle end to Canes Venatici’s brightest shining star.

How to Locate the Sunflower Galaxy
Image Credit: JPL Stellarium

Is the Sunflower Galaxy a Good Neighbor?

The Sunflower Galaxy belongs to the Messier 51 galaxy group, which gets its name from the nearby Whirlpool Galaxy, also known as M51A and NGC 5194, which is a grand spiral shape. 

Astronomers noted a faint arc loop in the Sunflower’s halo in 1979. It wasn’t until 2011 that they determined it was a stellar stream. They believe it appeared after a collision with a nearby dwarf satellite galaxy.

While the Sunflower is a good neighbor and mostly keeps to itself, dwarf galaxy M51B regularly interacts with nearby Whirlpool. The dwarf companion’s gravitational influence creates star formation within the larger Whirlpool Galaxy. 

The 400 million-year-old Whirlpool has a massive center, about 80-light years across. Its mass is approximately 40 million times that of the Sun. It also contains approximately 5,000 times more star concentration than the Milky Way. 

Other M51 galaxy group members include

  • NGC 5023 – An edge-on spiral galaxy
  • NGC 5229 – An edge-on spiral galaxy
  • UGC 8313 – A spiral bar galaxy
  • UGC 8331 – An irregular galaxy

Another galaxy group example is the compact group Stephan’s Quintet in the Pegasus Constellation. 


The Sunflower Galaxy is part of the M51 galaxy group. The bright yellow, dense core helps earn it the sunflower name. This flocculent spiral galaxy has periods of intense star formation within its bright starburst regions and the stellar nurseries of its cosmic dust lanes. 

Look to the northern sky in May for the best viewing of this colorful galaxy. While it is not visible to your naked eye, backyard astronomers appreciate long-exposure telescope images of the Sunflower Galaxy.