A spectroscopic survey of Herbig Ae/Be stars with X-Shooter - II. Accretion diagnostic lines

The Herbig Ae/Be stars (HAeBes) allow an exploration of the properties of pre-mainsequence(PMS) stars above the low-mass range (< 2M(circle dot)) and those bordering the high-mass range (> 8M(circle dot)). This paper is the second in a series exploring accretion in 91 HAeBes with Very Large Telescope/X-shooter spectra. Equivalent width measurements are carried out on 32 different lines, spanning the UV (ultraviolet) to NIR (near infrared), in order to obtain their line luminosities. The line luminosities were compared to accretion luminosities that were determined directly from measurements of a UV excess. When detected, emission lines always demonstrate a correlation with the accretion luminosity, regardless of detection frequency. The average relationship between accretion luminosity and line luminosity is found to be L-acc proportional to L-line (1.16 +/- 0.15). This is in agreement with the findings in Classical T Tauri stars, although the HAeBe relationship is generally steeper, particularly towards the Herbig Be mass range. Since all observed lines display a correlation with the accretion luminosity, all of them can be used as accretion tracers. This has increased the number of accretion diagnostic lines in HAeBes 10-fold. However, questions still remain on the physical origin of each line, which may not be due to accretion.