J/AJ/150/204 Spectroscopy of standard stars (Joner+, 2015)
Standard stars and empirical calibrations for Hα and Hβ photometry.
Joner M.D., Hintz E.G.
<Astron. J., 150, 204 (2015)>
=2015AJ....150..204J 2015AJ....150..204J (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Spectral types
Keywords: open clusters and associations: individual: (Hyades,Pleiades,Coma,
NGC 752) - techniques: photometric - techniques: spectroscopic
Abstract:
We define an Hα photometric system that is designed as a
companion to the well established Hβ index. The new system is
built on spectrophotometric observations of field stars as well as
stars in benchmark open clusters. We present data for 75 field stars,
12 stars from the Coma star cluster, 24 stars from the Hyades, 17
stars from the Pleiades, and 8 stars from NGC 752 to be used as
primary standard stars in the new systems. We show that the system
transformations are relatively insensitive to the shape of the filter
functions. We make comparisons of the Hα index to the Hβ
index and illustrate the relationship between the two systems. In
addition, we present relations that relate both hydrogen indices to
equivalent width and effective temperature. We derive equations to
calibrate both systems for Main Sequence stars with spectral types in
the range O9 to K2 for equivalent width and A2 to K2 for effective
temperature.
Description:
Between 2005 and 2015, spectroscopic data were obtained using the
1.2-m McKellar Telescope of the Dominion Astrophysical Observatory
(DAO). In total, data were secured on 153 nights using the telescope
in robotic mode. Observations were made using the Coude spectrograph
with the 3231 grating, which provided 40.9Å/mm. Using the Site4 CCD
with 15µm pixels gives 0.614Å/pixel. With 4096 pixels along the
dispersion axis, this provided a total coverage of approximately
2500Å. Aligning the grating to give a central wavelength of
5710Å allowed a spectral coverage from 4450 to 6970Å, which
provided coverage of both Hα and Hβ.
In total we examined 75 field stars (table2), 12 stars from the Coma
star cluster (table3), 24 from the Hyades (table4), 17 from the
Pleiades (table5), and 8 from NGC 752 (table6). These stars cover a
spectral type range from O9 to K2.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table2.dat 67 75 Hα and Hβ for selected field stars
table3.dat 67 12 Hα and Hβ for stars in the Coma cluster
table4.dat 67 24 Hα and Hβ for stars in the Hyades cluster
table5.dat 67 17 Hα and Hβ for stars in the Pleiades cluster
table6.dat 57 8 Hα and Hβ for stars in NGC 752
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See also:
J/ApJS/176/262 : VRI photometry in open clusters (Taylor+, 2008)
Byte-by-byte Description of file: table[2345].dat
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Bytes Format Units Label Explanations
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1 A1 --- f_HD Flag "A" indicates an additional star
3- 8 I6 --- HD [1280/285252]? HD number of the star
10- 19 A10 --- Name Star name (1)
21- 28 A8 --- SpT Spectral type
30- 36 F7.5 --- Halpha [2.6/2.91] The Hα index
38- 44 F7.5 --- e_Halpha [0/0.012] Error in Hα (σo)
46- 52 F7.5 --- Hbeta [2.5/2.91] The Hβ index
54- 60 F7.5 --- e_Hbeta [0.00029/0.027] Error in Hβ (σo)
62- 64 I3 --- No [2/191] Total number of observations
66- 67 I2 --- Nn [1/64] Number of nights observed
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Note (1): The star name is:
- Mostly the HR number in Table2;
- The Trumpler number (Trumpler 1938LicOB..18..167T 1938LicOB..18..167T) in Table3;
- The van Bueren number (Van Bueren, 1952BAN....11..385V 1952BAN....11..385V) in Table4;
- The Hertzsprung number (Hertzsprung, 1947AnLei..19A...1H 1947AnLei..19A...1H) or the star
name in Table5.
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Byte-by-byte Description of file: table6.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- BD ? BD number
11- 13 I3 --- Name [126/220] Star identification number from
Heinemann (1926AN....227..193H 1926AN....227..193H)
15- 20 A6 --- SpT Spectral type
22- 28 F7.5 --- Halpha [2.6/2.9] The Hα index
30- 36 F7.5 --- e_Halpha [0.002/0.01] Error in Hα
38- 44 F7.5 --- Hbeta [2.57/2.91] The Hβ index
46- 52 F7.5 --- e_Hbeta [0.0015/0.015] Error in Hβ
54- 55 I2 --- No [4/11] Total number of observations
57 I1 --- Nn [2/6] Number of nights observed
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History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 13-Jun-2016