J15368+6852sdO

PG1536+690 · 15:36:48.77 68:52:07.50 · Culpan knownhsd

outside the grid χ²/N = 0.97

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.

Results and provenance

Fit — Bamberg

T_eff [K]	58184 ± 624
log g	5.986 ± 0.119
log n(He)/n(H)	0.635 ± 0.170
reduced χ²	0.970 over 745 points
radial velocity	262.0 km s⁻¹
resolution (FWHM)	2.00 Å
lines fitted	15
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 19:09:28

Observation

telescope	SDSS 2.5-M
survey / programme	MWM / mwm_cb
field · MJD	101098 · 59977
date	2023-02-02
catalogid	27021597906720553
exposure	900 s in 1
airmass	1.64
seeing (50%)	1.82″
E(B−V)	0.026
pipeline	v6_2_1
cosmic rays	7 pixels cancelled
S/N (classifier)	29.6
source file	spec-101098-59977-27021597906720553.fits

Gaia astrometry

Gaia DR3 source	1647303168437152128
parallax [mas]	0.6573 ± 0.0314
G	14.619
BP − RP	-0.569
G_abs	3.701
μ_α [mas/yr]	-1.637
μ_δ [mas/yr]	-23.670
l, b	104.310, 41.775

Published (Culpan et al. 2022)

class (Culpan)	He-sdO
class (SIMBAD)	sdOC2VIIIHe40
T_eff [K]	63000 ± 2500
log g	5.80 ± 0.30
log y	1.00 ± 0.00
reference	1990A&A...235..234D

Classifier

DISPUTED

fitted Teff 63000 logg 5.8 logY 1.0 1990A&A...235..234D

auto: He II/He I 11.0, EW 1.66, Mg I b suggests a companion but Ca II does not (-0.5 sigma); contrast 0.03 over the 0.02 expected at 83 kK

Fitted lines

line	λ [Å]	shift [Å]	continuum at	±avg	fitted over
H_β	4861.32	4.25	-40.0, 40.0	5.0	-45.0, 45.0
H_γ	4340.46	3.79	-40.0, 36.8	4.5	-43.0, 43.0
H_δ	4101.73	3.58	-40.0, 31.6	4.2	-43.0, 43.0
H_ε	3970.07	3.47	-28.0, 30.0	4.1	-30.0, 35.0
H_ζ	3889.05	3.40	-20.0, 26.2	4.0	-31.8, 32.0
H_η	3835.38	3.35	-20.0, 14.6	4.0	-20.7, 21.8
H_θ	3797.90	3.32	-16.0, 16.0	3.9	-15.6, 16.7
H_ι	3770.63	3.30	-13.0, 13.0	3.9	-11.7, 11.6
He II 4686	4685.70	4.10	-11.9, 11.9	4.9	-15.0, 13.8
He II 5412	5411.52	4.73	-15.0, 15.0	5.6	-15.0, 15.0
He II 4542	4541.59	3.97	-15.0, 20.0	4.7	-20.0, 20.0
He II 4200	4199.84	3.67	-23.5, 33.8	4.3	-20.0, 20.0
He I 4472	4471.60	3.91	-15.0, 15.0	4.6	-15.0, 15.0
He I 4026	4026.29	3.52	-24.2, 15.0	4.2	-15.0, 15.0
He I 4922	4921.93	4.30	-15.0, 15.0	5.1	-15.0, 15.0