J16581+2140sdB

SDSSJ165809.14+214046.4 · 16:58:09.14 21:40:46.52 · Culpan knownhsd

χ²/N = 0.96

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

Observed spectrum in black, model in red, offset by line. Balmer series left, helium right.

Line-profile fit — uli

Observed spectrum in black, model in red, offset by line. Balmer series left, helium right.

Results and provenance

Fit — Bamberg

T_eff [K]	31718 ± 162
log g	6.112 ± 0.025
log n(He)/n(H)	-1.916 ± 0.041
reduced χ²	0.956 over 639 points
radial velocity	-72.0 km s⁻¹
resolution (FWHM)	2.00 Å
lines fitted	12
grids	HE-0.041.fits HE-0.125.fits HE-0.300.fits HE-0.550.fits +9 more
fitted	04/09/2026 19:09:48

Fit — uli

T_eff [K]	30502 ± 53
log g	6.074 ± 0.028
log n(He)/n(H)	-1.900 ± 0.039
reduced χ²	0.966 over 639 points
radial velocity	-72.0 km s⁻¹
resolution (FWHM)	2.00 Å
lines fitted	12
grids	h667.grid h909.grid h97.grid h99.grid +1 more
settled	outside the grid
fitted	04/09/2026 18:36:33

Observation

telescope	SDSS 2.5-M
survey / programme	boss
date	2011-04-02
exposure	5405 s in 12
pipeline	v5_13_2
S/N (classifier)	67.6
source file	spec-4178-55653-0182.fits

Gaia astrometry

Gaia DR3 source	4565075422721739648
parallax [mas]	0.7230 ± 0.0424
G	16.039
G_abs	5.344
μ_α [mas/yr]	-2.772
μ_δ [mas/yr]	-2.038
l, b	41.808, 34.112

Published (Culpan et al. 2022)

class (Culpan)	sdB
class (SIMBAD)	sdB0.5He9
T_eff [K]	32110 ± 336
log g	5.93 ± 0.08
log y	-2.13 ± 0.06
reference	2021ApJS..256...28L

Classifier

AGREES

fitted Teff 32110 logg 5.93 logY -2.13 2021ApJS..256...28L

auto: contrast 0.04, within the 0.29 a subdwarf reaches at 29 kK, Mg I b suggests a companion but Ca II does not (0.0 sigma)

Fitted lines

line	λ [Å]	shift [Å]	continuum at	±avg	fitted over
H_β	4861.32	-1.17	-40.0, 40.0	5.0	-45.0, 45.0
H_γ	4340.46	-1.04	-40.0, 36.8	4.5	-43.0, 43.0
H_δ	4101.73	-0.99	-40.0, 31.6	4.2	-43.0, 43.0
H_ε	3970.07	-0.95	-28.0, 30.0	4.1	-30.0, 35.0
H_ζ	3889.05	-0.93	-20.0, 26.2	4.0	-31.8, 32.0
H_η	3835.38	-0.92	-20.0, 14.6	4.0	-20.7, 21.8
H_θ	3797.90	-0.91	-16.0, 16.0	3.9	-15.6, 16.7
H_ι	3770.63	-0.91	-13.0, 13.0	3.9	-11.7, 11.6
He II 4686	4685.70	-1.13	-11.9, 11.9	4.9	-15.0, 13.8
He I 4472	4471.60	-1.07	-15.0, 15.0	4.6	-15.0, 15.0
He I 4026	4026.29	-0.97	-24.2, 15.0	4.2	-15.0, 15.0
He I 4922	4921.93	-1.18	-15.0, 15.0	5.1	-15.0, 15.0

Spectral energy distribution

T_eff 31718 K · log g 6.112 · E(44−55) 0.066 · χ²_r 0.65 over 38 bands

distance 1383 pc · parallax 0.7200 ± 0.0400 mas (6%) · R 0.1122 +0.0072 −0.0064 R☉ · M 0.595 +0.110 −0.091 M☉ — above the 0.47 canonical mass · L 11.5 +1.6 −1.3 L☉

Photometry against the model, with the residual beneath it in units of the error. The horizontal bar on each point is the passband, not an error; a hollow point was not fitted and the tooltip says why. Drag a box to zoom, double-click or Esc to come back out.