An aspect of my work led to a plane curve with implicit equation
$$
x^2+y^2 = 3 (y/2)^{2/3} + 1
$$
Actually, I started with the parametrization below and derived from it the
equation above:
```
\begin{eqnarray}
x(t) &=& t (3-2 t^2) \\
y(t) &=& 2(1-t^2)^{3/2}
\end{eqnarray}
```

Here is what it looks like:

If this falls in some classical class of curves, and perhaps even has a name, I would like to reference it appropriately. Does anyone recognize this curve? Thanks!

**Answered**. By Sylvain Bonnot and Francesco Polizzi: It is a type of *nephroid*!
Here's the Wikipedia image from the article they both cited: