J07488+4549sdB

SDSSJ074852.07+454903.9  ·  07:48:52.08 45:49:03.79  ·  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

profile fit on the Bamberg grid
Observed spectrum in black, model in red, offset by line. Balmer series left, helium right.

Line-profile fit — uli

profile fit on the uli grid
Observed spectrum in black, model in red, offset by line. Balmer series left, helium right.

Results and provenance

Fit — Bamberg

Teff [K]27698 ± 153
log g5.676 ± 0.025
log n(He)/n(H)-2.441 ± 0.043
reduced χ²0.985 over 639 points
radial velocity-174.0 km s−1
resolution (FWHM)2.00 Å
lines fitted12
gridsHE-0.041.fits
HE-0.125.fits
HE-0.300.fits
HE-0.550.fits
+9 more
fitted04/09/2026 19:07:42

Fit — uli

Teff [K]28244 ± 178
log g5.589 ± 0.026
log n(He)/n(H)-2.471 ± 0.045
reduced χ²0.982 over 639 points
radial velocity-174.0 km s−1
resolution (FWHM)2.00 Å
lines fitted12
gridsh667.grid
h909.grid
h97.grid
h99.grid
+1 more
fitted04/09/2026 18:34:50

Observation

telescopeSDSS 2.5-M
survey / programmeboss
date2009-12-13
exposure7203 s in 16
pipelinev5_13_2
S/N (classifier)75.4
source filespec-3673-55178-0190.fits

Gaia astrometry

Gaia DR3 source927227948229851392
parallax [mas]0.4672 ± 0.0464
G16.046
Gabs4.443
μα [mas/yr]-4.041
μδ [mas/yr]-5.123
l, b173.288, 28.738

Published (Culpan et al. 2022)

class (Culpan)sdB
class (SIMBAD)DAB
Teff [K]27217 ± 1129
log g5.51 ± 0.16
log y-2.30 ± 0.20
reference2017OAst...26..164G

Classifier

AGREES

fitted Teff 27217 logg 5.51 logY -2.3 2017OAst...26..164G

auto: contrast 0.11, within the 0.31 a subdwarf reaches at 27 kK, Ca II 8662/8542 = 8.9 -- the star's own Paschen lines, not a companion

Fitted lines

lineλ [Å]shift [Å]continuum at±avgfitted over
Hβ4861.32-2.82-40.0, 40.05.0-45.0, 45.0
Hγ4340.46-2.52-40.0, 36.84.5-43.0, 43.0
Hδ4101.73-2.38-40.0, 31.64.2-43.0, 43.0
Hε3970.07-2.30-28.0, 30.04.1-30.0, 35.0
Hζ3889.05-2.26-20.0, 26.24.0-31.8, 32.0
Hη3835.38-2.23-20.0, 14.64.0-20.7, 21.8
Hθ3797.90-2.20-16.0, 16.03.9-15.6, 16.7
Hι3770.63-2.19-13.0, 13.03.9-11.7, 11.6
He II 46864685.70-2.72-11.9, 11.94.9-15.0, 13.8
He I 44724471.60-2.60-15.0, 15.04.6-15.0, 15.0
He I 40264026.29-2.34-24.2, 15.04.2-15.0, 15.0
He I 49224921.93-2.86-15.0, 15.05.1-15.0, 15.0

Spectral energy distribution

Teff 27698 K · log g 5.676 · E(44−55) 0.048 · χ²r 0.27 over 35 bands

distance 2140 pc · parallax 0.4700 ± 0.0500 mas (11%) · R 0.1916 +0.0214 −0.0174 R☉ · M 0.635 +0.175 −0.128 M☉ — above the 0.47 canonical mass · L 19.5 +4.6 −3.4 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.