SIMBAD references

A sample of 46 deep, low mass ratio (DLMR) overcontact binaries (i.e., q ≤ 0.25 and f ≥ 50%) is statistically analyzed in this paper. It is found that five relations possibly exist among some physical parameters. The primary components are little-evolved main sequence stars that lie between the zero-age main sequence line and the terminal-age main sequence (TAMS) line. Meanwhile, the secondary components may be evolved stars above the TAMS line. The super-luminosities and large radii may result from energy transfer, which causes their volumes to expand. The equations of M-L and M-R for the components are also determined. The relation of P-M_total implies that mass may escape from the central system when the orbital period decreases. The minimum mass ratio may preliminarily be q_min = 0.044 (± 0.007) from the relations of q-f and q-J_spin/J_orb. With mass and angular momentum loss, the orbital period decreases, which finally causes this kind of DLMR overcontact binary to merge into a rapid-rotating single star.