Compiled catalogue of the MK spectral classifications, including astrometric and photometric data and its application
The catalogue constructed as a tool for stellar kinematic analysis is described. It contains up-todate information on spectral classifications in the MK system, positions and proper motions in the ICRS system, as well as BV magnitudes for 169 843 single stars. Astrometry and photometry were mainly s...
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| Опубліковано в: : | Кинематика и физика небесных тел |
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| Дата: | 2005 |
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| Мова: | English |
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Головна астрономічна обсерваторія НАН України
2005
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| Цитувати: | Compiled catalogue of the MK spectral classifications, including astrometric and photometric data and its application / S.P. Rybka // Кинематика и физика небесных тел. — 2005. — Т. 21, № 5-додаток. — С. 385-387. — Бібліогр.: 5 назв. — англ. |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine| id |
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Rybka, S.P. 2015-04-03T18:44:48Z 2015-04-03T18:44:48Z 2005 Compiled catalogue of the MK spectral classifications, including astrometric and photometric data and its application / S.P. Rybka // Кинематика и физика небесных тел. — 2005. — Т. 21, № 5-додаток. — С. 385-387. — Бібліогр.: 5 назв. — англ. 0233-7665 https://nasplib.isofts.kiev.ua/handle/123456789/79682 The catalogue constructed as a tool for stellar kinematic analysis is described. It contains up-todate information on spectral classifications in the MK system, positions and proper motions in the ICRS system, as well as BV magnitudes for 169 843 single stars. Astrometry and photometry were mainly selected from the Tycho-2. MK spectral types and luminosity classes were combined after revision of 11 original spectral catalogues, available from CDS. The first results of stellar kinematic analysis based on compiled catalogue are presented. en Головна астрономічна обсерваторія НАН України Кинематика и физика небесных тел MS4: Positional Astronomy and Global Geodynamics Compiled catalogue of the MK spectral classifications, including astrometric and photometric data and its application Article published earlier |
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Digital Library of Periodicals of National Academy of Sciences of Ukraine |
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DSpace DC |
| title |
Compiled catalogue of the MK spectral classifications, including astrometric and photometric data and its application |
| spellingShingle |
Compiled catalogue of the MK spectral classifications, including astrometric and photometric data and its application Rybka, S.P. MS4: Positional Astronomy and Global Geodynamics |
| title_short |
Compiled catalogue of the MK spectral classifications, including astrometric and photometric data and its application |
| title_full |
Compiled catalogue of the MK spectral classifications, including astrometric and photometric data and its application |
| title_fullStr |
Compiled catalogue of the MK spectral classifications, including astrometric and photometric data and its application |
| title_full_unstemmed |
Compiled catalogue of the MK spectral classifications, including astrometric and photometric data and its application |
| title_sort |
compiled catalogue of the mk spectral classifications, including astrometric and photometric data and its application |
| author |
Rybka, S.P. |
| author_facet |
Rybka, S.P. |
| topic |
MS4: Positional Astronomy and Global Geodynamics |
| topic_facet |
MS4: Positional Astronomy and Global Geodynamics |
| publishDate |
2005 |
| language |
English |
| container_title |
Кинематика и физика небесных тел |
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Головна астрономічна обсерваторія НАН України |
| format |
Article |
| description |
The catalogue constructed as a tool for stellar kinematic analysis is described. It contains up-todate information on spectral classifications in the MK system, positions and proper motions in the ICRS system, as well as BV magnitudes for 169 843 single stars. Astrometry and photometry were mainly selected from the Tycho-2. MK spectral types and luminosity classes were combined after revision of 11 original spectral catalogues, available from CDS. The first results of stellar kinematic analysis based on compiled catalogue are presented.
|
| issn |
0233-7665 |
| url |
https://nasplib.isofts.kiev.ua/handle/123456789/79682 |
| citation_txt |
Compiled catalogue of the MK spectral classifications, including astrometric and photometric data and its application / S.P. Rybka // Кинематика и физика небесных тел. — 2005. — Т. 21, № 5-додаток. — С. 385-387. — Бібліогр.: 5 назв. — англ. |
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AT rybkasp compiledcatalogueofthemkspectralclassificationsincludingastrometricandphotometricdataanditsapplication |
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2025-11-25T22:19:41Z |
| last_indexed |
2025-11-25T22:19:41Z |
| _version_ |
1850562652124741632 |
| fulltext |
COMPILED CATALOGUE OF THE MK SPECTRAL CLASSIFICATIONS,
INCLUDING ASTROMETRIC AND PHOTOMETRIC DATA
AND ITS APPLICATION
S. P. Rybka
Main Astronomical Observatory, NAS of Ukraine
27 Akademika Zabolotnoho Str., 03680 Kyiv, Ukraine
e-mail: rybka@mao.kiev.ua
The catalogue constructed as a tool for stellar kinematic analysis is described. It contains up-to-
date information on spectral classifications in the MK system, positions and proper motions in
the ICRS system, as well as BV magnitudes for 169 843 single stars. Astrometry and photometry
were mainly selected from the Tycho-2. MK spectral types and luminosity classes were combined
after revision of 11 original spectral catalogues, available from CDS. The first results of stellar
kinematic analysis based on compiled catalogue are presented.
INTRODUCTION
As is well recognized, the Hipparcos catalogue, provided the best quality proper motions and parallaxes in
the ICRS system, offers completely new possibilities for investigation of local galactic kinematics. Up to now,
there has been one of the most complicated kinematic problem associated with determination of galactic rotation
from proper motions referred to rotation frame. Since the Hipparcos catalogue has been constructed in a frame
with negligible rotation with respect to inertial one, it is possible, for the first time, to solve perfectly such
a problem. Indeed, uses of the Hipparcos data have already given considerable insight into the galactic rotation
problem as well as into the kinematic properties of local stellar populations. Moreover, newly released extensive
catalogues of high quality proper motions in the Hipparcos system can also be used for this purpose. The Tycho-2
is the largest among them. Recall that this all-sky catalogue contains proper motions and homogeneous two-
colour photometry for about 2.5 million stars. Consequently, the aim of the study presented here is to combine
high quality proper motions with astrophysic data into common catalogue in order to revise kinematics of
stars in the vicinity of the Sun. To compose the catalogue we have chosen the Tycho-2 as the main source of
proper motions and BV magnitudes for our compilation of known spectral classifications in the MK system,
is available from the CDS in Strasbourg. So, we attempted to built the compiled catalogue in such a way to
include the largest possible number of stars. The resulting catalogue of about 170 000 stars has been used to
redetermine the kinematic properties of main sequence stars and cool giants as a function of their spectra.
COMPILED CATALOGUE
In order to construct the compiled catalogue eleven spectral catalogues of the MK classifications were selected
from the CDS database. The main selection criteria were the follows: possibility of star identification in
astrometric catalogues and large comprehension of sources. As a result, all selected spectral catalogues contain
about 250 000 single stars in total. They combine MK spectral classifications from a wide variety of literature
sources, published in 1964–1999.
Searching for common stars was based on comparison of their coordinates (right ascension and declination)
from initial spectral catalogues. The coordinates were preliminary transformed to the same equinox (J2000.0)
and then they were sorted in right ascension order. Such a procedure allows to identify common objects in
effective manner. A search radius was adopted in the range of 0.5–1.5 arcminutes due to poor accuracy of
positions in spectral catalogues. The procedure was repeated a few times with increasing separation distance
and with excluding the identified stars. HD numbers or stellar magnitudes were additionally used for position
matches in unreliable cases. The resulting catalogue has no multiple entries for the same star. Data for every
star were extracted from a certain source catalogue in accordance with its priority assigned at the highest level
to the most recent source. The compiled list was then extended by including additional Hipparcos stars with
known MK classifications. Accurate positions, proper motions, and two-colour photometry in the catalogue
c© S. P. Rybka, 2004
385
presented here have been obtained by cross-referencing the Tycho-2 to general spectral catalogue. The ACT
and the Hipparcos catalogues have been additionally used for this purpose. Double, multiple, and variable stars,
as well as erroneous proper motions were excluded from the final version. As a result, it contains equatorial
coordinates and proper motions in the ICRS/J2000.0 system, BT and VT Tycho magnitudes, the MK spectral
classifications, the Tycho-2 identifier, and some other information for 169 843 stars down to VT = 11.5 mag.
Objects in the catalogue appear in order of right ascension increasing. The catalogue presents spectral type
data only as a temperature class, a subclass, and a luminosity class and puts that into identical format for every
star. Such a reformatting is necessary to use spectral classifications in statistical studies. Table 1 gives number
of stars distributed for spectral types and luminosity classes. Among 79 stars not included in the table there
are 40 subdwarfs and 39 carbon stars.
Table 1. Distribution of stars for spectral types and luminosity classes
Spectral type V IV III II I All stars
O 374 39 106 31 116 667
B 12788 3203 4908 1862 1430 24190
A 21210 5859 4053 1008 1010 33140
F 29891 2975 1578 416 423 35283
G 13915 5264 11083 501 276 31039
K 2582 1741 33472 788 267 38850
M 257 10 5887 259 172 6595
All stars 81017 19091 61087 4875 3694 169764
In the average the compiled catalogue is roughly ninety percent complete at VT =10.5 mag. Mean value
of VT is 8.7 and that of BT is 9.5 mag. The catalogue is available to public access on the following URL:
[http://www.mao.kiev.ua/dept/cat3.html].
APPLICATION OF COMPILED CATALOGUE
Starting with pioneering works by Schwarzschild, Lindblad, and Oort, the study of local stellar kinematics is
known to provide important information about the structure and evolution of the Milky Way. Recent advances
in such a study have been mainly achieved due to Hipparcos database, which combines considerable amount of
highly accurate proper motions and parallaxes with astrophysical data. In the present paper we have reanalysed
systematic and random motion of dwarf and giant populations taken from the catalogue compiled by us. Here
we briefly review some key results of the analysis.
The systematic velocity field of about 70 000 B−M type dwarfs and 40 000 G5−K5 type giants within
one kiloparsec of the Sun was investigated from the Ogorodnikov–Milne model of galactic rotation. This is
three-dimensional model, which has the great advantage of being independent of any a priori dynamical model
of the Galaxy. Most recently, Mignard [3] has used the same model to study of about 20 000 stars from
the Hipparcos catalogue. However, here we significantly extend the sample under investigation. For this reason
we are able to divide our sample into various spectral bins of typically 10 000 stars thus reaching more reliable
statistics. Moreover, spectroscopic parallaxes derived in this work have led to considerably larger distances
compared with those based on reliable Hipparcos parallaxes. Each spectral group may also be considered as
statistically unbiased sample, because we applied several criteria for selection of objects to avoid risking to
invalidate the conclusions. These criteria concern velocity, brightness and other properties of stars. Using
three-dimensional kinematic model we have determined its eight parameters and three components of the solar
motion with respect to various spectral groups. From the results it follows that the Oort–Lindblad model with
B, A, f , and K parameters is sufficient to describe the global galactic rotation of both dwarfs and giants,
belonging to disc population in the solar vicinity. Here B and A are the generalized Oort constants, f is
the phase offset, K is the local expansion or contraction. As expected for the first two parameters, they have
been estimated with high level of significance for all spectral groups. However, statistically significant values
of f , K parameters have been only detected for B−A dwarfs and G5−K0 giants. It is especially noteworthy
that there is a very close agreement between corresponding estimates of these parameters derived for young
and old stars. Thus, besides an overall galactic rotation both groups show a remarkably similar irregularities of
the systematic velocity field, characterized by the above parameters. These irregularities can be interpreted as
contracting motion at mean rate K = (−7.8±1.3) km s−1 kpc−1 and rotation around center, which lags by mean
angle f = 8.9◦ ± 1.7◦ from the adopted galactic center. The results are slightly sensitive to various distance
386
estimates based on spectroscopic or Hipparcos parallaxes. This gives some evidence that revealed anomalies of
kinematics may be real. The value of phase offset f determined here is well consistent with the value 6.2◦±1.5◦
obtained by Mignard [3] from three-dimensional analysis of Hipparcos data. However, he has not derived
significant values for K. The most probable cause of the discrepancy is using of different samples of stars due
to different stellar content of the Hipparcos and the Tycho-2 catalogues. Nevertheless, in roughly accordance
with ours negative non-zero values of K parameter can be found in paper [5] for young stars situated outside
the Gould Belt region. On the other hand, the group of K1−K5 giants exhibits only the familiar plane-parallel
galactic rotation described by the Oort’s constants A and B.
Using the estimates of Oort’s constants we calculated their relevant combination V = R(A − B), which
yields rotational speed of the Galaxy at solar distance R = 8.5 kpc [1] from its center. According to such
a relation the rotation velocity V = (202 ± 8) km s−1 for G5−K0 giants is the value slightly smaller than
the value V = (242 ± 7) km s−1 for early type dwarfs, but it is compatible with the V = (190 ± 9) km s−1
for later K1−K5 giants. The relatively slow galactic rotation of K−M giants V = (174 ± 6) km s−1 derived
by Miyamoto and Soma [4] from the ACRS Part 1 agrees quite well with our result for all giants considered.
It should also be noticed that the present determination of circular velocity of early type dwarfs is consistent
within the standard errors with recent value V = (231 ± 9) km s−1 estimated by Feast and Whitelock [1] from
Hipparcos proper motions and parallaxes of cepheids.
The distribution of peculiar velocities is also examined to determine the orientation and the shape of the ve-
locity ellipsoid as a function of stellar spectra. It has long been known that peculiar velocities of disc stars vary
with spectral types. However, due to the lack of accurate kinematic data, a detailed study of such a relation has
not been possible. The availability of Hipparcos parallaxes and proper motions allows to redetermine the ve-
locity distribution functions in the solar vicinity and represents a major advance over earlier work. A number
of studies have been devoted to derive the velocity ellipsoid parameters on this new base. In the present paper
we summarize our results obtained from analysis of significantly larger sample of stars. For all spectral types
we have obtained the classical order of principal axes of the velocity ellipsoid. It was also found that the vertex
deviation (galactic longitude of direction of the largest principal axis) declines and the shape of the velocity
ellipsoid gets rounder from early to late type stars. These conclusions are in a good agreement with those estab-
lished in recent works, for example [2]. The values of derived vertex deviations, commonly used to parameterize
the deviation from dynamical symmetry, are almost the same for both late type dwarfs and giants, thus yielding
mean value of the vertex deviation lv = 11.1◦±1.2◦. According to Gomez et al. [2] this indicates that the mean
age of both groups is also approximately equal and implies that there is dynamically significant evolution of
the Galaxy disc at this age.
CONCLUSIONS
From compiled astrometric and astrophysic data we have redetermined as a function of spectral types the kine-
matics of main sequence stars and cool giants in the solar neighbourhood within about 1 kpc. On account
of the unusually small accidental and systematic errors of the Tycho-2 proper motions we are able to de-
tect significant deviations of stellar systematic motion from Oort’s galactic rotation for early type dwarfs and
G5−K0 giants. We have also performed the study of peculiar velocities of all stars considered. The resulting
mean vertex deviation is 21.9◦ ± 1.4◦ and 11.1◦ ± 1.2◦ for young and old disc stars, respectively. In general,
the presented estimates are close enough to those quoted in recent papers. As noticed by Gomez et al. [2],
the persistence of the vertex deviation to late type stars implies that the Galaxy potential is significantly
non-axisymmetric at the solar radius. They also suggest that spiral arms are mainly responsible for the non-
axisymmetry.
[1] Feast M. W., Whitelock P. A. Hipparcos parallaxes and proper motions of cepheids and their implications //
Hipparcos – Venice 97: Proc. of the ESA Symposium / Ed. B. Battrick.–Noordwijk: ESA Publ., 1997.–P. 625–628.
[2] Gomez A. E., Grenier S., Udry S., et al. Kinematics of disk stars in the Solar neighbourhood // Hipparcos –
Venice 97: Proc. of the ESA Symposium / Ed. B. Battrick.–Noordwijk: ESA Publ., 1997.–P. 621–623.
[3] Mignard F. Local galactic kinematic from Hipparcos proper motions // Astron. and Astrophys.–2000.–354, N 2.–
P. 522–536.
[4] Miyamoto M., Soma M. Is the vorticity vector of the Galaxy perpendicular to the galactic plane? I. Precessional
correction and equinoctial motion correction to the FK5 system // Astron. J.–1993.–105, N 2.–P. 691–701.
[5] Torra J., Gomez A. E., Figueras F., et al. Young stars: irregularities of the velocity field // Hipparcos – Venice 97:
Proc. of the ESA Symposium / Ed. B. Battrick.–Noordwijk: ESA Publ., 1997.–P. 513–518.
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