Xuange is a white star in Boötes, the prototype of a class of stars whose surfaces are strangely poor in heavy elements such as iron.
At a glance
| type | white star (class A) |
|---|---|
| distance from the Sun | 99 light-years (30.4 pc) |
| its light left it | 99 years ago |
| luminosity | 21.6 × the Sun |
| radius | 1.65 × the Sun |
| surface temperature | 9,700 K |
| constellation | Bootes (Herdsman) |
Read off the piece’s own catalogue, the same values it draws with.
About Xuange
Xuange is a white star of class A, hotter and more luminous than the Sun. Its surface shows far less iron and similar metals than a star of its kind should, while lighter elements appear normal. Stars with this odd chemistry are named after it, the Lambda Boötis stars.
Its name comes from Chinese astronomy, from an asterism called the Black Spear, and was adopted by the International Astronomical Union recently.
What you see in the piece
From Earth Xuange is a faint star in Boötes. In the piece its colour is the clean white of its temperature; nothing on its surface reveals the chemistry that made it famous.
Measured or modelled
Why these stars lack heavy elements at their surfaces is not settled; one idea is that they have accreted gas from which dust, carrying the metals, had been removed.
Questions
What is a Lambda Boötis star?
A hot star whose surface is poor in iron and similar elements; Xuange, Lambda Boötis itself, is the prototype.