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Table 5

Spectral indices from Riddick et al. (2007, and reference therein) adopted in our analysis for spectral type classification.

Index Range of validity Numerator [nm] Denominator [nm]

VO 7445 M5−M8 0.5625 (735.0−740.0) + 0.4375 (751.0−756.0) 742.0−747.0
VO 2 M3−M8 792.0−796.0 813.0−815.0
c81 M2.5−M8 811.5−816.5 (786.5−791.5) + (849.0−854.0)
R1 M2.5−M8 802.5−813.0 801.5−802.5
R2 M3−M8 814.5−846.0 846.0−847.0
R3 M2.5−M8 (802.5−813.0) + (841.5−846.0) (801.5−802.5) + (846.0−847.0)
TiO 8465 M3−M8 840.5−842.5 845.5−847.5
PC3 M3−M8 823.5−826.5 754.0−758.0

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