Picture of the Day · NASA
NGC 3660 and Burçin's Galaxy
2026-05-26
The upper galaxy might be more photogenic, but the lower galaxy is more unusual. The galaxy up top is NGC 3660, a spiral galaxy similar to our own Milky Way galaxy in that it has several bright blue spiral arms and a central bar of stars, dust, and gas. Captured by chance in the featured deep and colorful image, surprisingly, is SN 2026cff, a supernova found just to the right of the central bar. Farther in the distance is the bottom galaxy, known informally as Burçin’s galaxy, but formally cataloged as LEDA 1000714. The center of this galaxy appears to be an old elliptical galaxy, but it is strangely surrounded by not one but two rings of stars. What created Burçin's galaxy is a mystery and remains a continuing topic of research, but it likely involves the accretion of one or more smaller galaxies.
via NASA APOD
Key facts
- Discovered by
- James Craig Watson
- Discovery date
- 25 November 1872
- Pronunciation
- / ˈ n ɛ m ɪ s ɪ s /
- Named after
- Nemesis
- Alternative designations
- A872 WA; 1952 HW 1
- Minor planet category
- main-belt · Nemesis
- Adjectives
- Nemesian / n ə ˈ m iː ʒ ( i ) ə n /
- Observation arc
- 144.93 yr (52,934 d)
- Aphelion
- 3.10 AU (463.69 Gm )
- Perihelion
- 2.40 AU (359.00 Gm)
- Semi major axis
- 2.75 AU (411.35 Gm)
- Orbital period sidereal
- 4.56 years (1,665 d)
- Mean anomaly
Wikidata facts
- Instance of
- asteroid
- Named after
- Nemesis
- Followed by
- 129 Antigone
- Follows
- 127 Johanna
- Parent body
- Sun
- Minor-planet group
- asteroid belt
- Diameter
- +162.515
- Orbital period
- +1665.678187935098
- Image
- 128 Nemesis (orbit).gif
Show 5 more facts
Article
128 Nemesis is a large 180 km main-belt asteroid, of carbonaceous composition. It rotates rather slowly, taking about 78 hours to complete one rotation. Nemesis is the largest member of the Nemesian asteroid family bearing its name. It was discovered by J. C. Watson on 25 November 1872, and named after Nemesis, the goddess of retribution in Greek mythology.
Diagram of Nemesis's orbit This object is orbiting the Sun with a period of 4.56 years and an eccentricity (ovalness) of 0.13. The orbital plane is inclined by 6.2° to the plane of the ecliptic. It is categorized as a C-type asteroid, indicating a primitive carbonaceous composition. Based on IRAS data Nemesis is about 188 km in diameter and is around the 33rd largest main-belt asteroid, while WISE measurements yield a size of ~163 km. The 77.81‑hour rotation period is the second longest for an asteroid more than 150 km in diameter.