# Rotational Velocity of Stars

### Description

A sample of rotational velocities of stars from Hoffleit and
Warren (1991) similar to that previosly considered by Pal, Woodroofe and Meyer (2007)
and used by Koenker and Mizera (2010). The `demo(velo)`

illustrates fitted
densities for three relatively weak concavity constraints corresponding to
*-1/sqrt(f)*, *-1/f* and *-1/f^2* constrained to be concave.
Note that last of these pushes the optimization methods about as far as they can do.

### Usage

1 | ```
velo
``` |

### Format

A numeric vector with 3933 observations on one variable.

`velo`

a numeric vector with rotational velocities.

### Source

Hoffleit, D. and Warren, W. H. (1991). The Bright Star Catalog (5th ed.). Yale University Observatory, New Haven.

### References

Pal, J. K., Woodroofe, M. and Meyer, M. (2007). Estimating a Polya frequency function. In Complex Datasets and Inverse Problems: Tomography, Networks and Beyond, (R. Liu, W. Strawderman, and C.-H. Zhang, eds.). IMS Lecture Notes-Monograph Series 54 239-249. Institute of Mathematical Statistics. Koenker, R. and Mizera, I. (2010) Quasi-Concave Density Estimation, Annals of Statistics, 38, 2998-3027.