J/AJ/141/53 Lick indices of type II Cepheid candidates (Schmidt+, 2011)
Spectra of type II Cepheid candidates and related stars.
Schmidt E.G., Rogalla D., Thacker-Lynn L.
<Astron. J., 141, 53 (2011)>
=2011AJ....141...53S 2011AJ....141...53S
ADC_Keywords: Stars, variable ; Spectroscopy
Keywords: stars: Population II; stars: variables: Cepheids
Abstract:
We present low-resolution spectra for variable stars in the Cepheid
period range from the ROTSE-I Demonstration Project and the All Sky
Automated Survey, some of which were previously identified as type II
Cepheid candidates. We have derived effective temperatures, gravities,
and metallicities from the spectra. Based on this, three types of
variables were identified: Cepheid strip stars, cool stars that lie
along the red subgiant and giant branch, and cool main-sequence stars.
Many fewer type II Cepheids were found than expected and most have
amplitudes less than 0.4mag. The cool variables include many likely
binaries as well as intrinsic variables. Variation among the
main-sequence stars is likely to be mostly due to binarity or stellar
activity.
Description:
We obtained spectra for 288 stars from Papers I (ANNN) and II (RNNN)
as well as 35 known Cepheids and 30 HD stars.
The spectra were obtained at Kitt Peak National Observatory during 14
nights in 2006 June, 2009 January, and 2009 April using the GoldCam
Spectrograph on the 2.1m telescope.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
stars.dat 34 353 Star list
table1.dat 75 615 Log of observations for 323 stars
table2.dat 200 672 LICK/IDS indices for 353 stars
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See also:
J/AJ/133/665 : Photometry of type II Cepheid candidates (Schmidt+, 2007)
J/AJ/137/4598 : VR light curve of ASAS-North Cepheids (Schmidt+, 2009)
Byte-by-byte Description of file: stars.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- Star Star name
12- 13 I2 h RAh SIMBAD right ascension (J2000)
15- 16 I2 min RAm SIMBAD right ascension (J2000)
18- 22 F5.2 s RAs SIMBAD right ascension (J2000)
24 A1 --- DE- SIMBAD declination sign (J2000)
25- 26 I2 deg DEd SIMBAD declination (J2000)
28- 29 I2 arcmin DEm SIMBAD declination (J2000)
31- 34 F4.1 arcsec DEs SIMBAD ? Declination (J2000)
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Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 18 A18 --- Type Star type (Classical Cepheids, Type II Cepheids,
Other Stars or Group [1-4]) (1)
20- 28 A9 --- Star Star name
29- 37 F9.5 d Per Period of variation
39- 42 F4.2 mag Amp Amplitude of variation
44- 50 F7.2 d HJD Heliocentric Julian Date of mid-exposure minus
2450000 (HJD-2450000)
52- 56 I5 K Teff ? Effective temperature
58- 61 F4.2 [cm/s2] log(g) ? Logarithm of surface gravity
63- 67 F5.2 [-] [Fe/H] ? Metallicity
69- 73 F5.2 mag E(V-R) ? The (V-R) color excess
75 A1 --- Notes [ab] References to notes (2)
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Note (1): The 4 groups are defined in the (Period,<V-R>) diagram (see section 3
of Paper II, Cat. J/AJ/137/4598) as follows:
Group 1 = includes the majority of the classical Cepheids
Group 2 = includes most of the type II Cepheids (P<2.2d)
Group 3 = includes red variables with long periods (could be reddened
Cepheids)
Group 4 = includes variables with periods appropriate with type II Cepheids,
but colors are much redder.
Note (2): Notes as follows:
a = only one reference star was used for the atmospheric parameters.
b = the calculated phase of the spectrum fell near maximum light when
V-R=0.09. This prevented a solution for the atmospheric parameters.
Within the accuracy of the period, the star could have actually been at
the point in its cycle just before the rapid rise to maximum with
V-R=0.32. This color permits a solution: Teff=5720K, log(g)=4.24,
[Fe/H]=-0.32, E(V-R)=-0.04. This would place it within the
Cepheid strip region after correction to the mean color.
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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- 9 A9 --- Star Star name
11- 17 F7.2 d HJD Heliocentric Julian Date (1)
19- 24 F6.3 mag CN1 LICK/IDS CN1 index
26- 31 F6.3 mag CN2 LICK/IDS CN2 index
33- 38 F6.3 0.1nm Ca4227 LICK/IDS Ca4227 index
40- 45 F6.3 0.1nm G4300 LICK/IDS G4300 index
47- 52 F6.3 0.1nm Fe4383 LICK/IDS Fe4383 index
54- 59 F6.3 0.1nm Ca4455 LICK/IDS Ca4455 index
61- 65 F5.3 0.1nm Fe4531 LICK/IDS Fe4531 index
67- 72 F6.3 0.1nm Fe4668 LICK/IDS Fe 4668 index
74- 79 F6.3 0.1nm Hb LICK/IDS Hβ index
81- 86 F6.3 0.1nm Fe5015 LICK/IDS Fe5015 index
88- 93 F6.3 mag Mg1 LICK/IDS Mg1 index
95-100 F6.3 mag Mg2 LICK/IDS Mg2 index
102-107 F6.3 0.1nm Mgb LICK/IDS Mgb index
109-114 F6.3 0.1nm Fe5270 LICK/IDS Fe5270 index
116-121 F6.3 0.1nm Fe5335 LICK/IDS Fe5335 index
123-128 F6.3 0.1nm Fe5406 LICK/IDS Fe5406 index
130-135 F6.3 0.1nm Fe5709 LICK/IDS Fe5709 index
137-142 F6.3 0.1nm Fe5782 LICK/IDS Fe5782 index
144-149 F6.3 0.1nm NaD LICK/IDS Na index
151-156 F6.3 0.1nm TiO1 LICK/IDS TiO1 index
158-163 F6.3 0.1nm TiO2 LICK/IDS TiO2 index
165-170 F6.3 0.1nm HdA LICK/IDS HδA index
172-178 F7.3 0.1nm HgA LICK/IDS HγA index
180-185 F6.3 0.1nm HdF LICK/IDS HδF index
187-192 F6.3 0.1nm HgF LICK/IDS HγF index
194-200 F7.3 0.1nm Ha LICK/IDS Hα index
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Note (1): of mid-exposure minus 2,450,000.
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History:
From electronic version of the journal
References:
Schmidt et al., Paper I, 2007AJ....133..665S 2007AJ....133..665S, Cat. J/AJ/133/665
Schmidt et al., Paper II, 2009AJ....137.4598S 2009AJ....137.4598S, Cat. J/AJ/137/4598
Schmidt et al., Paper IV, 2013AJ....146...61S 2013AJ....146...61S, Cat. J/AJ/146/61
(End) Greg Schwarz [AAS], Patricia Vannier [CDS] 24-Jul-2012