Kaus Media (Delta Sagittarii)

Kaus Media (Delta Sagittarii) is a star in the constellation Sagittarius, magnitude 2.7.

The middle of the Archer’s bow — an orange giant that may hide a white dwarf.

The Archer’s bow is drawn with three stars, and Kaus Media holds the middle — its name joins the Arabic qaws, “bow”, to the Latin media, “middle”. Kaus Borealis marks the bow’s northern tip and Kaus Australis its southern end.

It is an orange giant about three times the Sun’s mass. Though only some 260 million years old, it has already left the main sequence and is most likely fusing helium into carbon in its core.

It may not be alone. It has been listed as having a white dwarf companion — the dense, burnt-out core of a star that has already finished its life. Three much fainter stars, of magnitudes 13 to 15, also appear within a minute of arc of it.

Kaus Media (Delta Sagittarii) is 350 light-years away: the light we see from it set off around 1675, around the time Isaac Newton published his laws of motion and gravity.

Did you know?

• The Winnowing Basket. In Chinese astronomy Kaus Media is the second star of Jī, the Winnowing Basket, a group of four stars around the Teapot’s spout.
• A lunar mansion. In Hindu astrology this star is also called Purvashada, the name of one of the nakshatras, the lunar mansions.

An orange star of magnitude 2.7 where the Teapot’s lid meets its spout in Sagittarius. It is the middle of the three Kaus stars of the Archer’s bow; compare its orange with blue-white Kaus Australis just to the south.

What is a star?

When and where to see it

It is best placed in the evening sky around July, when it crosses the meridian at about 10 pm local time (around midnight in June). It can be seen from everywhere south of 60°N and never sets south of 60°S.

At its highest it stands 10° up from 50°N, 25° up from 35°N, 60° up from the equator, 85° up from 35°S.

Facts

Type

Star

Constellation

Sagittarius

Designations

Delta Sagittarii, δ Sgr, 19 Sgr, HR 6859, HD 168454, HIP 89931

Magnitude

2.7

Position

RA 18h 21.0m, Dec −29° 50′ (J2000)

Spectral type

K2.5IIIaCN0.5

Colour

orange-red (B−V 1.40)

Distance

350 light-years

Discovered

Known since antiquity

Open AstroPilot to see when Kaus Media (Delta Sagittarii) is highest tonight from your location, how easy it is with your telescope or binoculars, and an eyepiece view.