# Paikauhale (Tau Scorpii)

Paikauhale (Tau Scorpii) is a star in the constellation Scorpius, magnitude 2.8.

**The Hawaiian wanderer beside Antares — a young blue star that will become a red supergiant.**

In Hawaiian, Paikauhale means to go gadding about from house to house — a vagabond with no home. The star stands in a line of three with Hōkū-ʻula, Antares, and Au-haele. Arab astronomers saw it and Alniyat as al-niyāṭ, “the arteries”, flanking the Scorpion’s heart.

It is a young, hot [blue-white](https://astropilot.space/glossary/star-colour) star of 15 times the Sun’s mass, about 28,900 K at the surface and some 25,000 times as luminous, and only around 5 million years old. In about 6 million years it is expected to swell into a red supergiant hundreds of times the Sun’s width, much like the Antares it now sits beside.

It is also a puzzle. It spins slowly, once every 41 days, and has a magnetic field that astronomers have mapped across its surface. Its X-rays are unusually energetic, perhaps from clumps of hot gas falling back onto the star.

Paikauhale (Tau Scorpii) is 470 light-years away: the light we see from it set off around 1555, around the time Copernicus put the Sun at the centre of the Solar System.

## Did you know?

- **Wives of Djuit.** The Boorong people of north-western Victoria saw this star and Alniyat as the wives of Djuit, the star Antares.
- **Third star of the Heart.** In Chinese astronomy Paikauhale, Antares and Alniyat make up Xīn, the Heart. Paikauhale is its third star.
- **A family of thousands.** It belongs to the Upper Scorpius group, thousands of young stars that formed together and share a path through space.

A blue-white star of magnitude 2.8 just south-east of Antares; with Alniyat on the other side, it flanks the Scorpion’s red heart. Compare its icy colour with the deep orange-red of Antares.

## When and where to see it

It is best placed in the evening sky around June, when it crosses the meridian at about 10 pm local time (around midnight in June). It can be seen from everywhere south of 62°N and never sets south of 62°S.

At its highest it stands 12° up from 50°N, 27° up from 35°N, 62° up from the equator, 83° up from 35°S.

## Facts

- Type: Star
- Constellation: Scorpius
- Designations: Tau Scorpii, τ Sco, 23 Sco, HR 6165, HD 149438, HIP 81266
- Magnitude: 2.8
- Position: RA 16h 35.9m, Dec −28° 13′ (J2000)
- Spectral type: B0V
- Colour: blue-white (B−V -0.25)
- Distance: 470 light-years
- Discovered: Known since antiquity

Open AstroPilot to see when Paikauhale (Tau Scorpii) is highest tonight from your location, how easy it is with your telescope or binoculars, and an eyepiece view. https://astropilot.space/object/paikauhale