J16489+2458sdB
PG1646+250 · 16:48:58.78 24:58:01.85 · Culpan knownhsd
χ²/N = 0.98
Spectrum
shaded: the intervals the fit used · │ a cancelled pixeldrag on either panel to zoom · dbl-click or Esc to reset · arrows to pan
The whole reduced spectrum above, the region marked on it below. Shaded bands are the intervals the fit used; a tick under the axis marks a pixel the rejection mask cancelled.
Line-profile fit — Bamberg
Results and provenance
Fit — Bamberg
| Teff [K] | 24694 ± 414 |
| log g | 5.757 ± 0.054 |
| log n(He)/n(H) | -4.784 ± 5.209 |
| reduced χ² | 0.976 over 653 points |
| radial velocity | -77.0 km s−1 |
| resolution (FWHM) | 2.50 Å |
| lines fitted | 13 |
| grids | HE-0.041.fits HE-0.125.fits HE-0.300.fits HE-0.550.fits +9 more |
| fitted | 04/09/2026 18:32:18 |
Fit — Lei (TLUSTY)
| Teff [K] | 23390 ± 370 |
| log g | 5.720 ± 0.040 |
| log n(He)/n(H) | -3.000 ± 0.000 |
| grids | Lei et al. 2018, ApJ 868, 70 SYNSPEC 49 spectra from NLTE TLUSTY 204 model atmospheres, through XTgrid |
| helium | published as a limit |
Observation
| cosmic rays | 39 pixels cancelled |
| S/N (classifier) | 58.2 |
| source file | spec-57874-HD164832N263558M01_sp01-136.fits.gz |
Gaia astrometry
| Gaia DR3 source | 1300121926607765760 |
| parallax [mas] | 0.8972 ± 0.0377 |
| G | 16.046 |
| Gabs | 5.840 |
| μα [mas/yr] | 7.773 |
| μδ [mas/yr] | -10.129 |
| l, b | 44.884, 37.110 |
Published (Culpan et al. 2022)
| class (Culpan) | sdB |
| class (SIMBAD) | sdB |
| Teff [K] | 22001 ± 1143 |
| log g | 5.58 ± 0.16 |
| log y | -2.70 ± 0.20 |
| reference | 2017OAst...26..164G |
Classifier
AGREES
fitted Teff 22001 logg 5.58 logY -2.7 2017OAst...26..164G
auto: contrast 0.14, within the 0.38 a subdwarf reaches at 22 kK, Ca II 8662/8542 = 5.6 -- the star's own Paschen lines, not a companion
Fitted lines
| line | λ [Å] | shift [Å] | continuum at | ±avg | fitted over |
| Hβ | 4861.32 | -1.25 | -40.0, 40.0 | 5.0 | -45.0, 45.0 |
| Hγ | 4340.46 | -1.11 | -40.0, 36.8 | 4.5 | -43.0, 43.0 |
| Hδ | 4101.73 | -1.05 | -40.0, 31.6 | 4.2 | -43.0, 43.0 |
| Hε | 3970.07 | -1.02 | -28.0, 30.0 | 4.1 | -30.0, 35.0 |
| Hζ | 3889.05 | -1.00 | -20.0, 26.2 | 4.0 | -31.8, 32.0 |
| Hη | 3835.38 | -0.99 | -20.0, 14.6 | 4.0 | -20.7, 21.8 |
| Hθ | 3797.90 | -0.98 | -16.0, 16.0 | 3.9 | -15.6, 16.7 |
| Hι | 3770.63 | -0.97 | -13.0, 13.0 | 3.9 | -11.7, 11.6 |
| Hκ | 3750.15 | -0.96 | -10.0, 10.0 | 3.9 | -7.4, 8.7 |
| He II 4686 | 4685.70 | -1.20 | -11.9, 11.9 | 4.9 | -15.0, 13.8 |
| He I 4472 | 4471.60 | -1.15 | -15.0, 15.0 | 4.6 | -15.0, 15.0 |
| He I 4026 | 4026.29 | -1.03 | -24.2, 15.0 | 4.2 | -15.0, 15.0 |
| He I 4922 | 4921.93 | -1.26 | -15.0, 15.0 | 5.1 | -15.0, 15.0 |