J/other/IBVS/5633 Miras in Scorpius (Roslund+, 2005)
Periods of 54 known Miras and of 16 new ones in Scorpius.
Roslund C., Larsson A., Schalander P., Radbo M.
=2005IBVS.5633....1R 2005IBVS.5633....1R
ADC_Keywords: Stars, variable
Description:
In the recent IBVS 5633, Roslund et al. give a list of new red variable
stars. The work evidently was done in the early 1970s, but no effort
was made to match the star-list with recent data available from modern
on-line resources in this late publication. Johnson R magnitudes at
maximum are shown for all stars and spectral classifications for about
half. The authors warn that the magnitudes could have a systematic
error, such that they are perhaps a magnitude too bright overall.
Similarly, the coordinates, given to arcsecond precision, are noted as
being poorly determined with "a simple, unpretentious plate-measuring
machine of unproven accuracy." I confirm here both of these problems.
I have gone through the list to recover the stars in modern catalogues.
I matched the source-list in the Strasbourg VizieR utility against
UCAC2 and 2MASS, searching a 20" radius and assuming the brightest
red star in the region is the variable (typical J-K≫1.0). There are
no identification charts published, so misidentifications are possible.
However, the candidates are all very similar in near-IR brightness
(commonly 7<J<10), so it seemed the choices were limited. The original
positions are indeed semi-accurate, being typically 5"-15" in error.
I show improved coordinates in the table below. Nearly all
thepositions come from 2MASS, but a few appear in UCAC2.
That so few stars are present in UCAC2 is a first suggestion that
the Roslund et al red magnitudes are much too bright compared to the
standard system (either Johnson or Cousins R). I matched the corrected
positions again in VizieR with GSC-2.2, USNO-B1.0, and the DENIS
catalogue to obtain at least a "representative" V (or 'mv') magnitude,
sometimes inferred from adjacent colors. Most of these come from the
short-V plate data provided in GSC-2.2, where my experience with the
same sorts of stars suggests the zero-point and scale are under good
control. It was also easy to compare at the same time the Roslund
R(max) magnitudes with the photo-red and I-band data listed in the
three surveys just mentioned. This indicates the Roslund 'R' is at
least one and more likely two full magnitudes too bright even
accounting for the large amplitudes of the variables---the zero-point
is nearly that of the USNO-B1.0 or DENIS I-band magnitudes, rather
than R.
Finally, I matched the stars with the MSX6C and IRAS catalogues and
also GCVS v4.2. Most stars have an MSX link, but probably the bright
IR background close to the galactic center precluded many IRAS
detections. I also searched each position in SIMBAD (3' search
radius): the stars with Terzan links are shown, but the rest of
the stars are not present in the database.
Please note the following: where no reasonably bright red star
appeared near the Roslund position on 2MASS J-band images, I used the
identifications with the Terzan survey of the same region to obtain
improved positions. This allowed all but one star to be recovered
unambiguously.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table.dat 118 70 Periods of 54 known miras and of 16 new ones
in Scorpius
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See also:
V/114 : MSX6C Infrared Point Source Catalog (Egan+ 2003)
II/125 : IRAS catalogue of Point Sources, Version 2.0 (IPAC 1986)
Byte-by-byte Description of file: table.dat
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Bytes Format Units Label Explanations
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1- 9 A9 --- --- Label [RLS2005]
11- 12 I2 --- [RLS2005] Sequential number
13 A1 --- n_[RLS2005] [*] Individual note (1)
16- 17 I2 h RAh ? Right ascension (J2000)
19- 20 I2 min RAm ? Right ascension (J2000)
22- 26 F5.2 s RAs ? Right ascension (J2000)
28 A1 --- DE- Declination sign (J2000)
29- 30 I2 deg DEd ? Declination sign J2000)
32- 33 I2 arcmin DEm ? Declination sign J2000)
35- 38 F4.1 arcsec DEs ? Declination sign J2000)
40 A1 --- r_Pos [MU] Reference for position (2)
42- 58 A17 --- MSX6C MSX-C (Cat. V/114) designation
60- 69 A10 --- IRAS IRAS (Cat. II/125) designation
71- 74 F4.1 mag vmag ? Visual magnitude
77- 78 A2 --- SpType MK spectral type
79 A1 --- u_SpType Uncertainty flag on SpType
81-118 A38 --- Rem Remarks
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Note (1): Individual notes as follows:
[RLS2005] 24 = this is not IRAS 17094-3201 = MSX6C G353.4596+04.1748.
[RLS2005] 52 & 55 = variables 52 and 55 are moderately-close
red pairs of similar brightness and redness that were probably
merged on the plate material used for the survey. It is not
certain which of the stars (or both) is the intended variable.
Note (2): The reference is
M = 2MASS, 2003, Cat. II/246
U = UCAC2, 200Z, Cat. I/289
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Acknowledgements:
Brian Skiff, Lowell Observatory
(End) Patricia Vannier [CDS] 25-Aug-2005