stars                 package:rrcov                 R Documentation

_D_a_t_a _f_o_r _t_h_e _H_e_r_t_z_s_p_r_u_n_g-_R_u_s_s_e_l_l _D_i_a_g_r_a_m _o_f _t_h_e _s_t_a_r _c_l_u_s_t_e_r _C_Y_G _O_B_1

_D_e_s_c_r_i_p_t_i_o_n:

     Data for the Hertzsprung-Russell Diagram of the Star Cluster CYG
     OB1,  which contains 47 stars in the direction of Czgnus, from
     C.Doom. The first variable is the logarithm of the effective
     temperature at the surface of  the star (Te) and the second one is
     the logarithm of its light intencity (L/L0).

     In the Hertzsprung-Russell diagram, which is the scatterplot of
     these data points ,  where the log temperature is ploted from left
     to right, two groups of points are seen:  the majority which tend
     to follow a steep band and four stars in the upper corner.  In the
     astronomy the 43 stars are said to lie on the main sequence and
     the four  remaining stars are called giants (the points 11, 20,
     30, 34).

_U_s_a_g_e:

     data(stars)

_F_o_r_m_a_t:

     A data frame with 47 observations on the following 2 variables.

     '_X_1' Logarithm of the effective temperature at the surface of the
          star (Te)

     '_Y' Logarithm of its light intencity (L/L0)

     For convenience, the data sets 'stars.x', a matrix  with the first
     (independent) variable of the data frame,  and 'stars.y', the
     numeric vector giving the second (dependent)  variable, are
     provided as well.

_S_o_u_r_c_e:

     P. J. Rousseeuw and A. M. Leroy (1987)  _Robust Regression and
     Outlier Detection._ Wiley, p.27, table 3.

_E_x_a_m_p_l_e_s:

     data(stars)
     plot(stars)
     covMcd(stars)
     lm.stars <- lm(stars.y ~ stars.x)
     summary(lm.stars)
     plot(lm.stars)
     lts.stars<-ltsReg(stars.x, stars.y)
     plot(lts.stars)

