Antlia
What is Antlia?
Constellations· Spring evenings · empty sky south of Hydra. Lacaille's tribute to the air pump. A quiet patch of a few fourth-magnitude stars, with the Antlia galaxy cluster lying far beyond.
📍 Visible from where you are right now — computed in your browser
Stars of the figure
| Star | Magnitude |
|---|---|
| Alpha Antliae | 4.3 |
The 1 brightest of the 2 stars used in the figure (1 lines). Lower magnitude means brighter.
Constellation basics
| Season | Mar–Apr evenings, low in the south; visible from New York; only the northern part from London |
|---|---|
| Brightest star | α Antliae, mag 4.3 |
| How to find | south of Hydra's body, north of Vela |
| Area rank | 62nd of 88 |
Figures are representative approximations. Source: compiled from NASA and IAU public data.
U Antliae, one of the reddest stars in the sky
Antlia contains a red star called U Antliae. At around magnitude 5 to 6 it can be seen in binoculars. It is a carbon star, an old star that has brought carbon made deep inside up to its surface. Carbon in its atmosphere forms soot-like material that blocks blue light, which makes it one of the reddest-looking stars in the sky.
The ALMA radio telescope in Chile has imaged a thin, round shell of gas around the star, the trace of a short episode thousands of years ago when the star threw off material all at once. Carbon returned to space this way later becomes raw material for new stars and planets. The shell shows how an old star gives its matter back to space.
The constellation in depth
Antlia is one of the constellations Lacaille made in the 1750s to honour scientific instruments. It celebrates the air pump built by the French physicist Denis Papin, and its first name was the Pneumatic Machine. It is a small figure of a few fourth-magnitude stars in the wide, empty sky south of Hydra.
The brightest star, Alpha Antliae, is an orange giant of magnitude 4.3 about 370 light-years away. What makes Antlia interesting, though, lies far beyond its stars. About 130 million light-years away is the Antlia Cluster, a gathering of some 200 galaxies, and the fine spiral NGC 2997 can be seen with an amateur telescope.
Toward Antlia also lies Antlia 2, a satellite galaxy of the Milky Way discovered only in 2018. It is about 400,000 light-years away and spreads over an area as large as the Large Magellanic Cloud, yet its stars are so sparse that it is one of the faintest galaxies known. Sitting behind the Milky Way's dust, it was found only in the precise star positions measured by the Gaia spacecraft.
At declinations of −24° to −40° it can be seen from mid-northern latitudes such as New York, low in the south on March and April evenings. Look below the long body of Hydra and above Vela. In the Sky view, set New York on an April evening and it appears low in the southern sky.
Frequently asked
- When can I see Antlia?
- Antlia is best seen in Mar–Apr evenings, low in the south; visible from New York; only the northern part from London.
- How do I find Antlia?
- To find Antlia, look for south of Hydra's body, north of Vela.
- What is the brightest star in Antlia?
- The brightest star in Antlia is Alpha Antliae, at magnitude 4.3.
Related
Figures are representative approximations. Simulated positions use J2000 mean elements.