We present the distance-calibrated spectral energy distribution ( SED ) of TRAPPIST-1 using a new medium resolution ( R \sim 6000 ) near-infrared FIRE spectrum and its Gaia parallax .
We report an updated bolometric luminosity ( L _ { \mathrm { bol } } ) of -3.216 \pm 0.016 , along with semi-empirical fundamental parameters : effective temperature T _ { \mathrm { eff } } = 2628 \pm 42 K , mass= 90 \pm 8 ~ { } M _ { \mathrm { Jup } } , radius= 1.16 \pm 0.03 ~ { } R _ { \mathrm { Jup } } , and log g = 5.21 \pm 0.06 dex .
It ’ s kinematics point toward an older age while spectral indices indicate youth therefore , we compare the overall SED and near-infrared bands of TRAPPIST-1 to field-age , low-gravity , and low-metallicity dwarfs of similar T _ { \mathrm { eff } } and L _ { \mathrm { bol } } .
We find field dwarfs of similar T _ { \mathrm { eff } } and L _ { \mathrm { bol } } best fit the overall and band-by-band features of TRAPPIST-1 .
Additionally , we present new [ ] spectral indices for the SpeX SXD and FIRE spectra of TRAPPIST-1 , both classifying it as intermediate gravity .
Examining T _ { \mathrm { eff } } , L _ { \mathrm { bol } } , and absolute JHKW 1 W 2 magnitudes versus optical spectral type places TRAPPIST-1 in an ambiguous location containing both field- and intermediate-gravity sources .
Kinematics place TRAPPIST-1 within a subpopulation of intermediate-gravity sources lacking bonafide membership in a moving group with higher tangential and UVW velocities .
We conclude that TRAPPIST-1 is a field-age source with subtle spectral features reminiscent of a low surface gravity object .
To resolve the cause of TRAPPIST-1 ’ s intermediate gravity indicators we speculate two avenues which might be correlated to inflate the radius : ( 1 ) magnetic activity or ( 2 ) tidal interactions from planets .
We find the M8 dwarf LHS 132 is an excellent match to TRAPPIST-1 ’ s spectral peculiarities along with the M9 \beta dwarf 2MASS J10220489 + 0200477 , the L1 \beta 2MASS J10224821 + 5825453 , and the L0 \beta 2MASS J23224684 - 3133231 which have distinct kinematics making all three intriguing targets for future exoplanet studies .