J/A+A/551/A31 New spectral classification for hot subdwarfs (Drilling+, 2013)
An MK-like system of spectral classification for hot subdwarfs.
Drilling J.S., Jeffery C.S., Heber U., Moehler S., Napiwotzki R.
<Astron. Astrophys. 551, A31 (2013)>
=2013A&A...551A..31D 2013A&A...551A..31D
ADC_Keywords: Stars, early-type ; Stars, subdwarf ; MK spectral classification
Keywords: stars: early-type - subdwarfs - atmospheres
Abstract:
An MK (Morgan-Keenan)-like system of spectral classification for hot
subdwarfs is presented. We find that a three-dimensional spectral
type, consisting of a 'spectral' class, a 'luminosity' class, and a
'helium' class, is necessary to classify the sdO (subdwarf O) and sdB
(subdwarf B) stars. In addition, the helium-strong stars appear to
form two parallel spectral sequences: one showing strong lines of CII,
CIII, or CIV, and the other with these same lines weak or absent. We
also give a preliminary calibration of the new spectral types in terms
of effective temperature, surface gravity, and surface
helium-to-hydrogen abundance ratio, and show the relation between the
new spectral types and the natural groups defined by the PG
(Palomar-Green) survey.
Description:
The normalized, unsmoothed spectra used to determine all of the
spectral types given in Table 2 of this paper, including those of the
standard stars defining the new system, are included.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 61 76 Standard stars defining the new system
table2.dat 33 181 Spectral types for all stars in our sample
table3.dat 72 50 Atmospheric parameters used in the calibrations
index.dat 39 313 Summary of spectra in spectrum subdirectory
spectrum/* . 313 Individual spectra
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See also:
III/137 : Spectroscopically Identified Hot Subdwarf Stars (Kilkenny+ 1988)
J/A+A/317/689 : Hot subdwarfs proper motions (Thejll+ 1997)
J/AJ/126/1455 : 2MASS photometry of hot subdwarf stars (Stark+, 2003)
J/AJ/138/606 : Hot subdwarf stars in rejected PG catalog (Wade+, 2009)
J/A+A/530/A28 : New hot subdwarf stars (Oreiro+, 2011)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Star name
13- 17 F5.2 mag Bmag B magnitude
18 A1 --- u_Bmag Uncertainty flag on Bmag
20- 21 I2 h RAh Right ascension (J2000)
23- 24 I2 min RAm Right ascension (J2000)
26- 30 F5.2 s RAs Right ascension (J2000)
32 A1 --- DE- Declination sign (J2000)
33- 34 I2 deg DEd Declination (J2000)
36- 37 I2 arcmin DEm Declination (J2000)
39- 42 F4.1 arcsec DEs Declination (J2000)
44- 61 A18 --- SpType MK Spectral type
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Star name
14 A1 --- n_Name Individual note (1)
16- 33 A18 --- SpType MK Spectral type
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Note (1): Notes as follows:
a = lines unusually broad
b = unidentified absorption feature near λ4500Å
c = spectrum very noisy
d = unidentified broad absorption feature near λ4265Å,
λλ4326, 4627, 4703 emission
e = λλ4510, 4671, 4749, 4775 emission
f = λλ4324, 4509, 4637, 4774 emission
g = λλ4360, 4772 emission
h = HeI lines show wind profiles
i = weak G band?
j = λλ4325, 4651 emission
k = λλ4326, 4510-11, 4599-4601, 4615, 4776 emission
l = λλ4508, 4567, 4654-7, 4721, 4758, 4773 emission
m = λλ4326, 4510, 4704, 4760, 4775 emission
n = λλ4326, 4383, 4703, 4774 emission
o = λ4509 emission, weak G band?
p = λλ4369, 4409, 4792 emission
q = unidentified absorption feature near λ4530Å,
broad emission feature near λ4735Å
r = unusually narrow HeI λ4144 and CII λ4267
s = λλ4329, 4365, 4705, 4828 emission
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Byte-by-byte Description of file: table3.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- Name Star name
13- 14 I2 --- Ref Reference (1)
16- 19 F4.1 kK Teff Effective temperature
21- 24 F4.2 [cm/s2] logg Surface gravity
26- 30 F5.2 [-] log(He/H) [-4/2] Helium abundance (log[N(He)/N(H)]
32- 46 A15 --- SpType MK spectral type
49- 78 A30 --- Com Comments
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Note (1): References as follows:
1 = Dreizler et al. (1990A&A...235..234D 1990A&A...235..234D)
2 = Napiwotzki (1993AcA....43..343N 1993AcA....43..343N)
3 = Conlon et al. (1993A&A...269L...1C 1993A&A...269L...1C)
4 = Moehler et al. (1994A&A...282L..29M 1994A&A...282L..29M)
5 = Moehler and Heber (1998A&A...335..985M 1998A&A...335..985M)
6 = Maxted et al. (2001MNRAS.326.1391M 2001MNRAS.326.1391M)
7 = Ahmad and Jeffery (2003A&A...402..335A 2003A&A...402..335A)
8 = Morales-Rueda et al. (2003MNRAS.338..752M 2003MNRAS.338..752M)
9 = Ramspeck et al. (2001A&A...379..235R 2001A&A...379..235R)
10 = Schmidt (1996, Ph.D. Thesis, Universitat Bonn)
11 = Salomon (2003, Diploma thesis, Universitat Erlangen-Nurnberg)
12 = Hirsch (2009, Ph.D. Thesis, Universitat Erlangen-Nurnberg)
13 = Copperwheat et al. (2011MNRAS.415.1381C 2011MNRAS.415.1381C)
14 = this paper
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Byte-by-byte Description of file: index.dat
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Bytes Format Units Label Explanations
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1- 8 A8 --- FileName Spectrum file name in subdirectory spectrum
9- 15 I7 --- N [692/6888] Number of records in spectrum file
19- 29 A11 --- Name Star name (as in table 2)
31- 34 I4 0.1nm lam0 [3461/4572] Lower limit of wavelength range (Å)
36- 39 I4 0.1nm lam1 [4612/5531] Upper limit of wavelength range (Å)
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Byte-by-byte Description of file: spectrum/*
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Bytes Format Units Label Explanations
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1- 7 F7.2 0.1nm lambda Wavelength
8- 18 F11.6 --- Flux ?=* Normalized flux (continuum = 1)
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Acknowledgements:
John Drilling, johndrilling(at)comcast.net
References:
Dreizler et al., 1990A&A...235..234D 1990A&A...235..234D
Jeffery et al., 1997A&AS..125..501J 1997A&AS..125..501J
Moehler et al., 1990A&AS...86...53M 1990A&AS...86...53M
Moehler et al., 1990A&A...239..265M 1990A&A...239..265M
Moehler et al., 1994A&A...282L..29M 1994A&A...282L..29M
Theissen et al., 1993A&A...273..524T 1993A&A...273..524T
Theissen et al., 1995A&A...298..577T 1995A&A...298..577T
History:
* 20-Jul-2013: on-line table2 and spectra
* 22-Oct-2013: tables 1 and 3 added
(End) John Drilling [LSU, USA], Patricia Vannier [CDS] 20-Dec-2012