TITLE: Recognize this plane curve?
QUESTION [5 upvotes]: 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:

REPLY [11 votes]: 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.

REPLY [7 votes]: Pretty curve...I think it is a Nephroid:
http://en.wikipedia.org/wiki/Nephroid