J/AJ/122/1486 NGC 2451A proper motions and membership (Platais+, 2001)
WIYN open cluster study. VII. NGC 2451A and the Hipparcos distance scale.
Platais I., Kozhurina-Platais V., Barnes S., Girard T.M., Demarque P.,
van Altena W.F., Deliyannis C.P., Horch E.
<Astron. J. 122, 1486 (2001)>
=2001AJ....122.1486P 2001AJ....122.1486P
ADC_Keywords: Clusters, open ; Proper motions ; Radial velocities ;
Photometry, UBV
Keywords: astrometry - color-magnitude diagrams -
open clusters and associations: individual (NGC 2451A)
Abstract:
We provide new evidence that NGC 2451A is undoubtedly a young open
cluster, although sparsely populated. New cluster membership has been
derived from relative proper motions of 5868 stars. In total, 136
stars down to V∼15 5 have membership probability Pµ≥2%. New CCD BV
photometry indicates that about 70 stars are indeed main-sequence
stars of NGC 2451A. This is also supported by our measurements of
radial velocities. A total of 34 very likely cluster members yield a
mean heliocentric radial velocity for NGC 2451A equal to +22.9km/s.
The high quality of our BV photometry, a confirmation of cluster
membership from proper motions and radial velocities, and a recently
obtained metallicity estimate for several cluster stars allow us to
perform a precise isochrone fit. The Yale isochrones, updated by the
latest available input physics, have been fitted to the cluster's
color-magnitude diagram, yielding a distance modulus V0-MV in the
range 6.35 to 6.38, which is in excellent agreement with the distance
modulus (m-M)0=6.38 derived from the Hipparcos data recently by van
Leeuwen and Robichon et al. (1998, Cat. J/A+AS/130/157).
We have used the high-resolution spectra acquired using the Hydra
multiobject spectrograph at the WIYN telescope (Kitt Peak, Arizona) in
1997 November and 1998 October.
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table1.dat 65 136 Astrometry and photometry for probable cluster
members in NGC 2451A
table3.dat 34 67 Radial velocities
spm.dat 129 5868 Catalog of positions, relative proper motions
and BV photographic photometry in the region of
open cluster NGC 2451
ccd.dat 71 14836 Catalog of CCD BV photometry in the region of
open cluster NGC 2451
--------------------------------------------------------------------------------
See also:
http://www.astro.yale.edu/astrom : SPM Home Page
I/252 : The USNO-A2.0 Catalogue (Monet+ 1998)
I/277 : SPM catalog 2.0 (Platais+, 1998)
J/AJ/124/601 : WIYN Open Cluster Study. VIII (Platais+, 2002)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- PKB Running identification number,
Cl* NGC 2451 PKB NNNNN in Simbad
6- 8 I3 --- Will ? The Williams (1967MNSSA..26...30W 1967MNSSA..26...30W) number,
NGC 2451 NNN in Simbad
10 I1 h RAh Right Ascension (J2000, epoch J2000) (1)
12- 13 I2 min RAm Right Ascension (J2000, epoch J2000) (1)
15- 20 F6.3 s RAs Right Ascension (J2000, epoch J2000) (1)
22 A1 --- DE- Declination sign (J2000, epoch J2000) (1)
23- 24 I2 deg DEd Declination (J2000, epoch J2000) (1)
26- 27 I2 arcmin DEm Declination (J2000, epoch J2000) (1)
29- 33 F5.2 arcsec DEs Declination (J2000, epoch J2000) (1)
35- 39 F5.1 mas/yr pmX Relative proper motion along X (2)
41- 44 F4.1 mas/yr pmY Relative proper motion along Y (2)
46- 51 F6.3 mag Vmag The Johnson V band magnitude
53 A1 --- r_Vmag [aeu] Source of Vmag (3)
55- 60 F6.3 mag B-V The (B-V) color
62 I1 --- o_Vmag Number of observations for Vmag
64- 65 I2 % Prob Cluster membership probability
--------------------------------------------------------------------------------
Note (1): Epoch and equinox J2000.
Note (2): Relative proper motions to X, Y directions, specified in spm.dat file.
Note (3): Reference for photometry:
a = B and V photometry adopted from Hipparcos, Cat. I/239
e = B and V photometry from SPM photometry (see Sec.2.2)
u = B and V photometry from Williams (1967MNSSA..26...30W 1967MNSSA..26...30W)
--------------------------------------------------------------------------------
Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 4 I4 --- PKB Running identification number,
Cl* NGC 2451 PKB NNNNN in Simbad
6- 16 F11.3 d HJD Heliocentric Julian date
18- 23 F6.2 km/s HRV Heliocentric radial velocity
24 A1 --- n_HRV [a] indicates a broad cross-correlation peak
27- 30 A4 --- Memb Membership status based on membership
probability (2)
--------------------------------------------------------------------------------
Note (2): Membership status:
ms: star located on the main sequence of NGC 2451A or up to 0.75mag above
B-cl: probable NGC 2451B members
fld: star located below or well above the main sequence of NGC 2451A,
considered as field star
--------------------------------------------------------------------------------
Byte-by-byte Description of file: spm.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
2- 5 I4 --- PKB Running identification number,
Cl* NGC 2451 PKB NNNNN in Simbad
7- 12 F6.2 mm Xpos X position (1)
14- 19 F6.2 mm Ypos Y position (1)
21- 30 F10.7 rad RArad Right ascension for the epoch 1991.25
and in the ICRS reference system
(i.e. equinox 2000.0)
32- 41 F10.7 rad DErad Declination for the epoch 1991.25 and
equinox 2000.0
43- 45 I3 mas e_RArad Estimated standard error in right ascension
multiplied by cos(DE)
47- 49 I3 mas e_DErad Estimated standard error in declination
51- 56 F6.1 mas/yr pmRA Relative proper motion in right ascension
multiplied by cos(DE)
58- 63 F6.1 mas/yr pmDE Relative proper motion in declination
65- 66 I2 --- o_Bmag The number of grating images per star detected
on blue plates (grating image pairs are
counted as one image)
68- 69 I2 --- o_Vmag The number of grating images per star on
visual plates
71- 74 F4.1 mas/yr e_pmRA Estimated standard error in right ascension's
proper motion
76- 79 F4.1 mas/yr e_pmDE Estimated standard error in declination's
proper motion
81- 85 F5.2 mag Bmag ?=0.00 Photographic B-magnitude
(if missing then set to 0.00)
87- 90 F4.2 mag e_Bmag Estimated standard error of B-magnitude
92- 96 F5.2 mag Vmag ?=0.00 Photographic V-magnitude
(if missing then set to 0.00)
98-101 F4.2 mag e_Vmag Estimated standard error of V-magnitude
103-108 F6.3 mag Vmagc ?=-1.000 CCD V-magnitude
(if missing then set to -1.000)
110-115 F6.3 mag B-Vc ?=-1.000 CCD B-V color
(if missing then set to -1.000)
117-121 F5.3 mag e_Vmagc IRAF generated error in CCD V-magnitude
123-127 F5.3 mag e_B-Vc IRAF generated error in CCD B-V color
129 I1 --- Nframe [0/4]? Number of frames per star (G1)
--------------------------------------------------------------------------------
Note (1): Approximate rectangular coordinates on the SPM plate #18.
The scale of SPM plates is 55.1"/mm. East is in the direction of
increasing X, North is in the direction of Y.
--------------------------------------------------------------------------------
Byte-by-byte Description of file: ccd.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 9 I9 --- Seq Object identifier (1)
11- 19 F9.5 deg RAdeg Right ascension
(mean epoch=1996.6, equinox J2000.0)
21- 29 F9.5 deg DEdeg Declination (mean epoch=1996.6, equinox J2000.0)
31- 36 F6.3 mag Vmag CCD V magnitude
38- 43 F6.3 mag B-V CCD B-V magnitude
45- 49 F5.3 mag e_Vmag IRAF generated error in CCD V-magnitude
51- 55 F5.3 mag e_B-V IRAF generated error in CCD B-V color
57- 62 F6.3 arcsec DRA "CCD-USNOA2.0" (I/252) coordinate difference
in right ascension multiplied by cos(DE)
64- 69 F6.3 arcsec DDE "CCD-USNOA2.0" (I/252) coordinate difference
in declination
71 I1 --- Nframe [1/4] Number of frames per star (G1)
--------------------------------------------------------------------------------
Note (1): Normally, first four digits indicate the probable NGC 2451A member
which usually was placed at the center of CCD chip
--------------------------------------------------------------------------------
Global notes:
Note (G1): Number of frames per star:
If it is 2, 3, or 4 then mean CCD BV magnitudes have been averaged
from 2, 3, or 4 frames. (Note that for spm.dat, many entries entirely
miss this item!)
--------------------------------------------------------------------------------
History:
From electronic version of the journal
References:
Von Hippel & Sarajedini, Pap I 1998AJ....116.1789V 1998AJ....116.1789V
Sarajedini et al., Pap II 1999AJ....118.2894S 1999AJ....118.2894S
Sarajedini, Pap III 1999AJ....118.2321S 1999AJ....118.2321S
Sarajedini et al., Pap IV 1999AJ....118.2894S 1999AJ....118.2894S
Barrado et al., Pap V 2001ApJ...549..452B 2001ApJ...549..452B
Sills & Sarajedini, Pap VI 2000ApJ...544..944S 2000ApJ...544..944S
Platais et al., Pap VIII 2002AJ....124..601P 2002AJ....124..601P, Cat. J/AJ/124/601
Stassun et al., Pap IX 2002A&A...382..899S 2002A&A...382..899S, Cat. J/A+A/382/899
Grocholski & Sarajedini Pap X 2002AJ....123.1603G 2002AJ....123.1603G
von Hippel et al., Pap XI 2002AJ....124.1555V 2002AJ....124.1555V
Deliyannis et al., Pap XII 2002ApJ...577L..39D 2002ApJ...577L..39D
Barnes Pap XIII 2003ApJ...586..464B 2003ApJ...586..464B
Barnes Pap XIV 2003ApJ...586L.145B 2003ApJ...586L.145B
Kafka & Honeycutt, Pap XV 2003AJ....126..276K 2003AJ....126..276K
Grocholski & Sarajedini, Pap XVI 2003MNRAS.345.1015G 2003MNRAS.345.1015G
Platais et al., Pap XVII 2003AJ....126.2922P 2003AJ....126.2922P, Cat. J/AJ/126/2922
Mathieu et al., Pap XVIII 2004ApJ...602L.121M 2004ApJ...602L.121M
Sarajedini, et al., Pap XIX 2004AJ....127..991S 2004AJ....127..991S
Kafka et al., Pap XX 2004AJ....127.1622K 2004AJ....127.1622K
Steinhauer & Deliyannis, Pap XXI 2004ApJ...614L..65S 2004ApJ...614L..65S
Meibom & Mathieu, Pap XXII 2005ApJ...620..970M 2005ApJ...620..970M
von Hippel et al., Pap XXIII 2006ApJ...645.1436V 2006ApJ...645.1436V
Hole et al. Pap XXIV 2009AJ....138..159H 2009AJ....138..159H, Cat. J/AJ/138/159
James et al., Pap XXV
Platais et al., Pap XXVI 2007A&A...461..509P 2007A&A...461..509P, Cat. J/A+A/461/509
Kafka et al., Pap XXVII
Giampapa et al., Pap XXVIII 2006ApJ...651..444G 2006ApJ...651..444G
Meibom et al., Pap XXIX 2006ApJ...653..621M 2006ApJ...653..621M
Jeffery et al., Pap XXX 2007ApJ...658..391J 2007ApJ...658..391J
Meibom et al., Pap XXXI 2007ApJ...665L.155M 2007ApJ...665L.155M
Geller et al., Pap XXXII 2008AJ....135.2264G 2008AJ....135.2264G, Cat. J/AJ/135/2264
Yadav et al., Pap XXXIII 2008A&A...484..609Y 2008A&A...484..609Y, Cat. J/A+A/484/609
Meibom et al., Pap XXXIV 2009ApJ...695..679M 2009ApJ...695..679M, Cat. J/ApJ/695/679
Platais et al., Pap XXXV 2008MNRAS.391.1482P 2008MNRAS.391.1482P, Cat. J/MNRAS/391/1482
Geller et al., Pap XXXVI 2009AJ....137.3743G 2009AJ....137.3743G, Cat. J/AJ/137/3743
Meibom et al., Pap XXXVII 2009AJ....137.5086M 2009AJ....137.5086M, Cat. J/AJ/137/5086
Geller et al., Pap XXXVIII 2010AJ....139.1383G 2010AJ....139.1383G, Cat. J/AJ/139/1383
Anthony-Twarog et al., Pap XXXIX 2010AJ....139.2034A 2010AJ....139.2034A, Cat. J/AJ/139/2034
Sarajedini et al., Pap XL 2009ApJ...698.1872S 2009ApJ...698.1872S
Chumak et al., Pap XLI 2010MNRAS.402.1841C 2010MNRAS.402.1841C
Casetti-Dinescu et al., Pap XLII 2010AJ....139.1889C 2010AJ....139.1889C
James et al., Pap XLIII 2010A&A...515A.100J 2010A&A...515A.100J, Cat. J/A+A/515/A100
Platais et al., Pap XLIV 2011MNRAS.413.1024P 2011MNRAS.413.1024P, Cat. J/MNRAS/413/1024
Meibom et al., Pap XLV 2011ApJ...733..115M 2011ApJ...733..115M, Cat. J/ApJ/733/115
Platais et al., Pap XLVI 2011ApJ...733L...1P 2011ApJ...733L...1P
Gosnell et al., Pap XLVII 2012ApJ...745...57G 2012ApJ...745...57G
Geller & Mathieu Pap XLVIII 2012AJ....144...54G 2012AJ....144...54G
Platais et al., Pap XLIX 2012ApJ...751L...8P 2012ApJ...751L...8P
Cummings et al., Pap L 2012AJ....144..137C 2012AJ....144..137C
Geller et al., Pap LI 2013AJ....145....8G 2013AJ....145....8G
Yang et al., Pap LII 2013ApJ...762....3Y 2013ApJ...762....3Y
Sandquist et al., Pap LIII 2013ApJ...762...58S 2013ApJ...762...58S
Anthony-Twarog, Pap LIV 2013ApJ...767L..19A 2013ApJ...767L..19A
Platais et al., Pap LV 2013AJ....146...43P 2013AJ....146...43P, Cat. J/AJ/146/43
Pap LVI
Maderak et al., Pap LVII 2013AJ....146..143M 2013AJ....146..143M
Pap LVIII
Tofflemire et al., Pap LIX 2014AJ....148...61T 2014AJ....148...61T, Cat. J/AJ/148/61
Milliman et al., Pap LX 2014AJ....148...38M 2014AJ....148...38M, Cat. J/AJ/148/38
Anthony-Twarog et al., Pap LXI 2014AJ....148...51A 2014AJ....148...51A, Cat. J/AJ/148/51
Thompson et al., Pap LXII 2014AJ....148...85T 2014AJ....148...85T, Cat. J/AJ/148/85
Maderak et al., Pap LXIII 2015AJ....149..141M 2015AJ....149..141M
Lee-Brown et al., Pap LXV 2015AJ....149..121L 2015AJ....149..121L, Cat. J/AJ/149/121
Leiner et al., Pap LXVI 2015AJ....150...10L 2015AJ....150...10L, Cat. J/AJ/150/10
Geller et al. Pap LXVII 2015AJ....150...97G 2015AJ....150...97G, cat. J/AJ/150/97
Pap LXVIII
Pap LXIX
Pap LXX
Milliman et al., Pap LXXI 2016AJ....151..152M 2016AJ....151..152M, cat. J/AJ/151/152
Anthony-Twarog et al., Pap LXXII 2016AJ....152..192A 2016AJ....152..192A, cat. J/AJ/152/192
Pap LXXIII
Pap LXXIV
Cummings et al., Pap LXXV 2017AJ....153..128C 2017AJ....153..128C
Anthony-Twarog et al., Pap LXXVI 2018AJ....155..138A 2018AJ....155..138A
(End) Greg Schwarz [AAS], Patricia Bauer [CDS] 14-Jan-2002