See Astron. J. 107, 280 (1994) for more detailed description of the original compilation.
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DESCRIPTION:
The U.S. Naval Observatory Catalog of Positions of Infrared Stellar Sources (CPIRSS) was originally compiled in 1994 to provide astrometry at the sub-arcsecond level for many of the point sources in the 1987 version of the IRAS Point Source Catalog (NASA RP-1190). This was accomplished by the identification of IRAS sources with bright optical stars, checked by requiring the color V-[12] (with [12] being a magnitude derived by the IRAS flux) to be consistent with the optical colors or spectral type. Additionally, the K magnitude (2.2 microns) has been estimated. The latest version, completed in 2001, contains 37,700 stars and includes the Hipparcos and Tycho-2 astrometry and photometry which was unavailable at the time of the original compilation.
The data are available at NASA's Astronomical Data Center by clicking HERE.
For a description of the 1994 compilation, click here HERE.
INTRODUCTION:
The Infrared Astronomical Satellite (IRAS) carried out an all-sky survey at 12, 25, 60 and 100 microns. Approximately 250 000 point sources were identified. However, by the standards of optical astrometry, the positions of these sources are poorly determined, with errors of tens of arc-seconds. Optical astrometric catalogs such as Hipparcos (ESA 1997) and Tycho-2 (Hoeg et al. 2000) have errors in position under 0.1 arc-seconds, some two to three orders of magnitude less than the IRAS positions.
Many of the sources in the IRAS Point Source Catalog (1987, hereafter referred to as PSC) have been identified as stars. Thus it is possible to construct a higher quality astrometric catalog of infrared sources by combining these positions with the IRAS identifications. However, because the IRAS positions have such large errors, the identifications provided in the PSC are suspect. The V-[12] color, with [12] being a magnitude determined from the 12 micron flux, is very sensitive to temperature. If the optical identification of an IRAS source is correct, the V-[12] color should be consistent with optical colors or spectral type. Once a cross-correlation is established, an estimation of the Johnson system K magnitudes is made. Hindsley and Harrington (1994) describe the details on the confirmation identification based on color and the K magnitude determination.
The CPIRSS has had two upgrades following the 1994 release; one in 1996 and one in 2001. In 1996, 4022 new sources were added, bringing the total to 37,700. As with the 33,678 stars in the original CPIRSS, the positional matches were checked by using the optical colors and visual magnitudes to estimate the 12 micron magnitudes, which were compared to the actual IRAS 12 micron measurement. Stars with an estimate that do not match the observations are included in the catalog but flagged so that the user is aware of the questionable identification. Also in 1996, the record number in the IRAS Point Source Catalog was added to each record. The 1996 version also had various errata corrected.
In 2001, better astrometry was substituted. Of the 37,700 stars, all but 105 were found in either the Hipparcos or Tycho-2 catalogs (Cat. , ). Since these surpass the accuracies found in the astrometric catalogs used in earlier versions, their values were added. Given the availability of both for a star, the Hipparcos data take precedence. Both Hipparcos and Tycho-2 numbers are provided, along with several flags that can give users warning of possible multiplicity or non-linear proper motions. At the same time, the V magnitudes from Hipparcos or Tycho-2 were substituted for the poorer values found in the previously used astrometric catalogs. Since much of the original work was performed using those older values, differences between them and the current values are provided for the user.
Earlier versions of this work not put into the Astronomical Data Centers, but were made available through the U.S. Naval Observatory.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
cpirss01.dat 288 37000 The CPIRSS (2001) catalog
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Byte-by-byte Description of file: cpirss01.dat
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Bytes Format Units Label Explanations
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001-010 A10 --- DM_ID Primary Durchmusterung identifier
012-022 A12 --- PSC_ID1 IRAS PSC identifier
024-029 I6 --- PSC_ID2 IRAS PSC record number
031-032 I2 h RAh R.A. (hours), epoch=2000.0, HCRS
033-034 I2 min RAmin R.A. (minutes), epoch=2000.0, HCRS
035-040 F6.3 s RAs R.A. (seconds), epoch=2000.0, HCRS
042-048 F7.3 s/cy pmRA Prop. mot. in RA, seconds/century
050-050 A1 --- Decl. (sign), epoch=2000.0, HCRS
051-052 I2 deg DEd Decl. (degree), epoch=2000.0, HCRS
053-054 I2 arcmin DEm Decl. (minutes), epoch=2000.0, HCRS
055-059 F5.2 arcsec DEs Decl. (seconds), epoch=2000.0, HCRS
061-067 F7.3 arcsec/cy pmDE Prop. mot. in Decl., arcsec/century
069-070 I2 --- r_Pos *Source of position
072-080 E9.7 Jy Fnu_12 IRAS flux density, 12 micron
081-089 E9.7 Jy Fnu_25 IRAS flux density, 25 micron
090-098 E9.7 Jy Fnu_60 IRAS flux density, 60 micron
099-107 E9.7 Jy Fnu_100 IRAS flux density, 100 micron
108-114 F7.3 mag Vmag *Observed V magnitude
115-121 F7.3 mag Vdiff *Vmag(previous) - Vmag(cpirss2001)
123-123 I1 --- r_Vmag *Source of V magnitude
125-139 A15 --- SpType *Spectral type
140-141 I2 --- r_SpType *Source of Spectral Type
143-148 F6.3 mag Color Color
150-150 A1 --- Fcolor *Flag for color
152-157 F6.3 mag Excess *B-V color excess
159-159 I1 --- Method *Method used in color confirmation
161-166 F6.2 mag Deviat *Color deviation
168-168 I1 --- Confrm *Result of color confirmation
170-175 F6.3 mag Kmag Estimated K magnitude
177-177 I1 --- Qual_12 *IRAS Flux quality indicator; 12 microns
178-178 I1 --- Qual_25 *IRAS Flux quality indicator; 25 microns
179-179 I1 --- Qual_60 *IRAS Flux quality indicator; 60 microns
180-180 I1 --- Qual_100 *IRAS Flux quality indicator; 100 microns
182-182 A1 --- Corr_12 *IRAS correlation coeff.; 12 microns
183-183 A1 --- Corr_25 *IRAS correlation coeff.; 25 microns
184-184 A1 --- Corr_60 *IRAS correlation coeff.; 60 microns
185-185 A1 --- Corr_100 *IRAS correlation coeff.; 100 microns
187-188 I2 --- Vari *Probability (0%-99%) of variability
190-196 A7 --- WDS *WDS id code (discoverer & number)
197-201 A5 --- WDS_comp *WDS components
203-206 I4 yr WDS_yr Year of last observation in WDS
208-210 I3 deg WDS_theta Position angle at last obs. in WDS
212-216 F5.1 arcsec WDS_rho Separation at last obs. in WDS
218-222 F5.2 mag WDS_mag1 V magnitude of primary in WDS
224-228 F5.2 mag WDS_mag2 V magnitude of secondary in WDS
230-230 A1 --- WDS_orb *Orbit flag
231-236 I6 --- HIP Hipparcos number
237-237 A1 --- H10 *HIP field 10; double and mult. system
238-238 A1 --- H59 *HIP field 59; annex flag
239-250 I12 --- Tyc2 *Tycho-2 number
251-251 A1 --- T10 *Tycho-1 field 10; Ref. for astrometry
252-252 A1 --- T40 *Tycho-1 field 40; Astrometric Quality
253-253 A1 --- T49 *Tycho-1 field 49; Duplicity from Tycho-1
254-254 A1 Tpflag *Tycho-2 position flag
255-255 A1 --- Tposflg *Tycho-2 posflg, astrometric treatment
256-256 A1 --- dupflg *CPIRSS duplicity flag
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Note on r_Pos:
This field is the source of astrometry.
4 = Astrographic Catalogue Reference Stars (ACRS)
6 = Positions and Proper Motions Catalog (PPM)
7 = Smithsonian Astrophysical Observatory Star Catalog (SAO)
10 = Hipparcos
11 = Tycho-2
Note on Vmag and Vdiff:
These fields give the current, best values for Vmag, as well as
information regarding these parameters in previous releases of
the CPIRSS. It was decided to provide the best V magnitude available,
so many values have been replaced from earlier releases. When the
Vmag data are from Hipparcos, the values from Hipparcos H5
field were used. Where the Vmag data are from Tycho-2, the values
from VT were used with no converversion to the Johnson system attempted.
Since the color confirmation and K magnitude estimates were made using
older data, it was decided to provide users a way to compute these older
values. The field Vdiff is the value of the older Vmag - current Vmag.
Note on r_Vmag:
This field it the source of the observed V magnitude
1 = Mermilliod 1991
2 = Lanz 1986
8 = From Astrographic Catalogue Reference Stars
9 = From the same catalog as the positional information
Data NOT from Mermilliod 1991, Lanz 1986, Hipparcos or Tycho-2 is
deemed somewhat unreliable.
Note on SpType and r_SpType:
These fields are for the spectral type and its source
For r_SpType,
1 = MK Extension catalog (Morris-Kennedy 1983)
2 = Michigan HD catalog (Houk & Cowley 1975)
3 = Henry Draper catalog (Cannon & Pickering 1918-24)
4 = Average of MK Ext. data(1) and Michigan HD data(2)
Positive values of the source mean the raw entries have been
"interpreted" (eg, a spectral subtype of 3+ in the MK Exten-
sion catalog has been converted into 3.5). A negative source
value means that the data are directly from the catalog.
Note that the result of averaging (source = 4) is occasionally
a subclass not represented in either catalog. For example,
K5 & M0 are averaged to produce K7.5, although neither the
MK Extension catalog nor the Michigan HD catalog have any
spectral subtypes between K5 and M0. The spectral types are
used for determining intrinsic colors, and the fictitious
subtype K7.5 is useful for interpolating. Also note that the
result of averaging luminosity classes can be intermediate
between two classes. This is indicated by a value in
bytes 166:168 (eg, .5, .75). Such a value as 'IV .25'
should be interpreted as being 0.25 of the way from luminosity
class IV toward V. Again the point is to allow interpolation,
in this case for calculating absolute magnitudes.
Note on Fcolor:
This field is the flag for the color field.
'1'= Intrinsic (not reddened) B-V
'2'= Observed (reddened) B-V
'3'= Observed (reddened) R-I
Note on Excess:
This field is the B-V color excess. Its interpretation depends on
field 'Confrm' (byte 190). If byte 190 is 1, this
was calculated as the difference (observed color - intrinsic color).
Otherwise this was calculated from the coordinates and the relationships
of Arenou, Grenon, and Gomez (1992). Blank means assumed zero if byte 190
is 1,2,3,4, or 5; otherwise, blank means it cannot be estimated.
Note on Method:
This field indicates the method used in color confirmation
0 = insufficient data available, no color confirmation attempted
1 = both B-V and spectral type available
2 = only spectral type (with luminosity class) available
3 = only spectral type (without luminosity class) available
4 = B-V only available (no spectral type)
5 = R-I used; either no B-V data at all, or not both B-V and spectral type
data (case 1 above). R-I used in this case if available because
it is less sensitive to reddening.
Note on Deviat:
If this value is lower than 20.0, then then this is the deviation
([calculated from color confirmation] - [observed from IRAS])
in magnitudes. For values greater than 20.0, the color confirmation
could not be attempted and the value indicates what data are lacking,
with the following meaning.
21.0 = IRAS 12 micron flux is a lower limit
22.0 = IRAS variability probability > 50%
23.0 = Color data indicates multiplicity
24.0 = Color data indicates variability
25.0 = Spectral type data indicates multiplicity
26.0 = Spectral type data indicates variability
27.0 = Spectral type data indicates peculiarity
(eg, Carbon star, Am star, emission or peculiar)
28.0 = No observed V magnitude
29.0 = No observed color or spectral type data
30.0 = Color too red: (B-V) > 1.60, cannot analyze
31.0 = Reddening < -0.15; indicates spectral type data
or photometry is in error (probably one data set does not apply
to this star or is contaminated by a double).
Note on Confrm:
This field shows the results of the color confirmation.
1 = Optical and IRAS match confirmed
2 = Optical and IRAS match questionable
0 = No color confirmation attempted
Note on Qual_12, Qual_25, Qual_60, Qual_100:
These fields are the IRAS Flux quality indicators.
1 = Upper limit
2 = Moderate quality
3 = High quality
Note on Corr_12, Corr_25, Corr_60, Corr_100:
These fields are the IRAS point source correlation coefficents.
A =100%, B =99%, etc. See IRAS Point Source Catalog, col. 14.
Note on Vari:
This field indicates the percent probability of variability.
A value of -1 means the source was not examined for variability.
Note on WDS:
These fields give data from the Washington Double Stars (WDS) catalog.
(Worley and Douglass 1984)
Note on WDS_comp
This filed gives data on the components. AB means data for components
A and B. A-BC means secondary component consists of a double. Etc.
Note on WDS_orb:
This field indicates an orbit is available in the WDS catalog.
'O' = Orbit available
' ' = No orbit available
Note on H10:
This field is the Hipparcos field 10, reference flag for astrometry
A,B,... = The specified component of multiple system.
@ = Photocenter of multiple system. See HIP-C annex.
+ = Center of mass. See HIP-O annex.
Note on H59:
This field is the Hipparcos field 59, double/multiple system flag.
C = Component solutions available from Hipparcos
G = acceleration terms available from Hipparcos
O = Orbital solutions available from Hipparcos
V = variability induced mover from Hipparcos
Note on Tyc2:
This field gives the Tycho-2 identification number. Note that if the
star was in Tycho-1 but not Tycho-2, the Tycho-1 ID is given.
Blanks are replaced with zeros.
Note on T10
This field is the Tycho-1 field 10, reference flag for Tycho-1 astrometry
'X' = Indication of a dubious astrometric reference star.
Note on T40:
This field is the Tycho-1 field 40, astrometric quality flag
' ' = HIP star not observed by Tycho.
1 to 4 = very high to high quality.
5 = medium quality.
6 = perhaps non-single.
7 = low quality.
8 = perhaps non-stellar.
9 = low quality; position derived from TICR.
Note on T49:
This field is the Tycho-1 filed 49, duplicity flag.
' ' = HIP star not observed by Tycho.
'D' = Duplicity clearly indicated.
'R' = duplicity weakly indicated.
'S' = duplicity suspected.
'Y' = investigation made; no indication of duplicity found.
'Z' = investigation for duplicity not made.
Note on Tpflag:
This field is the Tycho-2 pflag, it has the following meaning.
' ' = normal mean position and proper motion
'P' = astrometry from photocenter of two Tycho-2 stars
'X' = no mean position, proper motion in Tycho-2
Note on Tposflag:
This field is the Tycho-2 posflg, and describes what treatment method the
Tycho-2 data utilized to get position.
' ' = normal treatment in Tycho-2
'D' = double star treatment
'P' = photocenter treatment
Note on dupflg:
This field is an attempt to summarize many of the WDS, Hipparcos,
Tycho-1 and Tycho-2 flags found above into one flag.
' ' = astrometry does not indicate duplicity
'1' = astrometry does indicate duplicity
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REGERENCES:
A tridimensional model of the galactic interstellar extinction, 1992, Arenou, F., Grenon, M., and Gomez, A., Astron & Astrophys., 258, 104. =1992A&A...258..104A
The Henry Draper Catalog, 1918-1924, Cannon, A.J., & Pickering, E.C., Ann. Astron. Obs. Harvard College, 91-99 (from CDROM).
University of Michigan Catalogue of Two-Dimensional Spectral Types for the HD Stars, vol. 1, 1975, Houk, N. and Cowley, A.P., (this and vol. 2, 3, and 4 from CDROM).
IRAS Catalogues and Atlases: The Explanatory Supplement, 1987, eds. C.A. Bechman, G. Neugebauer, H.J. Habing, P.E. Clegg, T.J. Chester, NASA RP-1190, vol. 1.
IRAS Catalogues and Atlases: The Point Source Catalog, 1987, eds. C.A. Bechman, G. Neugebauer, H.J. Habing, P.E. Clegg, T.J. Chester, NASA RP-1190, vol. 2-6 (from CDROM).
Photoelectric Photometric Catalogue in the Johnson UBVRI System, 1986 Lanz, T., A&A Suppl., 6, 195 (from CDROM) =1986A&AS...65..195L
Homogeneous Means in the UBV System, 1991, Mermilliod, J.-C., unpublished (from CDROM)
MK Classification System, 1983, Morris-Kennedy, P., unpublished (from CDROM).
Selected Astronomical Catalogs, 1991, vol. 1, No. 1 (USA_NASA_ADC_CAT_0011), Astronomical Data Center, Goddard Space Flight Center, NASA (CDROM).
Superseded Washington Double Star Catalog, 1984, Worley, C.E., and Douglass, G.G., unpublished (from CDROM).
The U.S. Naval Observatory Catalog of Positions of Infrared Stellar Sources, 1994, Hindsley R. and Harrington R., Astron. Journal 107 280 =1994AJ....107..280H
The Hipparcos and Tycho Catalogues, 1997, ESA SP-1200, =1997HIP...C......0E
The Tycho-2 Catalogue of the 2.5 Million Brightest Stars Hog E., Fabricius C., Makarov V.V., Urban S., Corbin T., Wycoff G., Bastian U., Schwekendiek P., Wicenec A. Astron. Astrophys. 355, 27 (2000), =2000A&A...355L..27H
Last update: September 20, 2001
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