J16534+2056sdB

SDSSJ165325.75+205659.1 · 16:53:25.75 20:56:59.17 · Culpan knownhsd

outside the grid χ²/N = 1.00

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]	29700 ± 203
log g	5.628 ± 0.031
log n(He)/n(H)	-5.937 ± 0.949 upper limit
reduced χ²	1.002 over 639 points
radial velocity	-18.0 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
settled	outside the grid
fitted	04/09/2026 19:09:47

Fit — uli

T_eff [K]	30235 ± 151
log g	5.554 ± 0.032
log n(He)/n(H)	-3.398 ± 0.063 upper limit
reduced χ²	1.002 over 639 points
radial velocity	-18.0 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)	62.0
source file	spec-4178-55653-0420.fits

Gaia astrometry

Gaia DR3 source	4564642112060408960
parallax [mas]	0.4114 ± 0.0433
G	16.209
G_abs	4.284
μ_α [mas/yr]	-4.715
μ_δ [mas/yr]	0.705
l, b	40.536, 34.914

Published (Culpan et al. 2022)

class (Culpan)	sdB
class (SIMBAD)	sdO

Classifier

AGREES

auto: contrast 0.11, within the 0.27 a subdwarf reaches at 30 kK, Mg I b suggests a companion but Ca II does not (-0.6 sigma)

Fitted lines

line	λ [Å]	shift [Å]	continuum at	±avg	fitted over
H_β	4861.32	-0.29	-40.0, 40.0	5.0	-45.0, 45.0
H_γ	4340.46	-0.26	-40.0, 36.8	4.5	-43.0, 43.0
H_δ	4101.73	-0.25	-40.0, 31.6	4.2	-43.0, 43.0
H_ε	3970.07	-0.24	-28.0, 30.0	4.1	-30.0, 35.0
H_ζ	3889.05	-0.23	-20.0, 26.2	4.0	-31.8, 32.0
H_η	3835.38	-0.23	-20.0, 14.6	4.0	-20.7, 21.8
H_θ	3797.90	-0.23	-16.0, 16.0	3.9	-15.6, 16.7
H_ι	3770.63	-0.23	-13.0, 13.0	3.9	-11.7, 11.6
He II 4686	4685.70	-0.28	-11.9, 11.9	4.9	-15.0, 13.8
He I 4472	4471.60	-0.27	-15.0, 15.0	4.6	-15.0, 15.0
He I 4026	4026.29	-0.24	-24.2, 15.0	4.2	-15.0, 15.0
He I 4922	4921.93	-0.30	-15.0, 15.0	5.1	-15.0, 15.0

Spectral energy distribution

T_eff 29700 K · log g 5.628 · E(44−55) 0.058 · χ²_r 0.13 over 38 bands

distance 2431 pc · parallax 0.4100 ± 0.0400 mas (10%) · R 0.1904 +0.0226 −0.0182 R☉ · M 0.563 +0.163 −0.118 M☉ · L 25.4 +6.4 −4.7 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.