Question: 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:

![Plots](https://i.stack.imgur.com/AoNAF.jpg)

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:

          ![Wiki image](https://upload.wikimedia.org/wikipedia/commons/0/02/EpitrochoidOn2.gif)

Answer: 
Your curve is a *nephroid*, see <http://en.wikipedia.org/wiki/Nephroid>.

The general equation of such a plane curve is $$(x^2+y^2-4a^2)^3=108a^4y^2.$$ Your example corresponds to the value $a=\frac{1}{2}$ of the parameter.
Pretty curve...I think it is a Nephroid:
<http://en.wikipedia.org/wiki/Nephroid>