Table 4
Lyα values for LTT 1445A and GJ 486.
| LTT 1445A | GJ 486 | |
|---|---|---|
| Reconstruction from STIS/G140M | ||
| log10(Surface flux) (erg cm−2 s−1) |  |
 |
| log10(N(H I)) (cm−2) | 17.8 ± 0.1 | 17 8±0 1 |
| H I radial velocity (km s−1 ) |  |
 |
| Estimate from UV–UV correlations | ||
| log10(Surface flux) from Si III (erg cm−12 s−1) | 5 37 ± 0 23 | 5 48 ± 0 23 |
| log10(Surface Flux) from N V (erg cm−2 s−1) | 5.30 ± 0.35 | 5 49 ± 0 35 |
| log10(Surface Flux) from Si II (erg cm−2 s−1) | 5.02 ± 0.30 | 5 52 ± 0 30 |
| log10(Surface Flux) from C II (erg cm−2 s−1) | 5.48 ± 0.40 | 5 84 ± 0 40 |
| log10(Surface Flux) from Si IV (erg cm−2 s−1) | 5.39 ± 0.38 | 5 14 ± 0 38 |
| log10(Surface Flux) from C IV (erg cm−2 s−1) | 5.36 ± 0.32 | 5 15 ± 0 32 |
| log10(Surface Flux) from He II (erg cm−2 s−1) | 5.47 ± 0.32 | 5 23 ± 0 32 |
| log10(Surface Flux) from Mg II (erg cm−2 s−1) | 5.43 ± 0.19 | 5 22 ± 0 19 |
| log10(Surface flux) mean (erg cm−2 s−1) | 5.35 ± 0.31 | 5 19 ± 0 30(a) |
Notes. Log surface fluxes calculated using distances and stellar radii from Table 1.(a) For GJ 486 we find that lines measured with the COS/G130M grating give systematically higher estimates of the Lyα flux. Given that two large flares were removed from the data taken with this grating, it is possible that the transition region lines we measure with COS/G130M are not completely representative of a quiescent state. We therefore report the Lyα estimate from the UV–UV correlations only with lines in the G160M and G230L gratings for LTT 1445A.
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