J/MNRAS/459/880 Open clusters in Auriga OB2 (Marco+, 2016)
Open clusters in Auriga OB2.
Marco A., Negueruela I.
<Mon. Not. R. Astron. Soc. 459, 880 (2016)>
=2016MNRAS.459..880M 2016MNRAS.459..880M (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Photometry, infrared ; Photometry, uvby
Keywords: stars: early-type - stars: evolution -
Hertzsprung-Russell and colour-magnitude diagrams -
open clusters and associations: individual: Alicante 11 -
open clusters and associations: individual: Alicante 12 -
open clusters and associations: individual: Stock 8
Abstract:
We study the area around the HII region Sh 2-234, including the young
open cluster Stock 8, to investigate the extent and definition of the
association Aur OB2 and the possible role of triggering in massive
cluster formation. We obtained Stromgren and J, H, Ks photometry for
Stock 8 and Stromgren photometry for two other cluster candidates in
the area, which we confirm as young open clusters and name Alicante 11
and Alicante 12. We took spectroscopy of ∼33 early-type stars in the
area, including the brightest cluster members. We calculate a common
distance of 2.80+0.27-0.24kpc for the three open clusters and
surrounding association. We derive an age 4-6Ma for Stock 8, and do
not find a significantly different age for the other clusters or the
association. The star LS V +34 23, with spectral type O8 II(f), is
likely the main source of ionization of Sh 2-234. We observe an
important population of pre-main-sequence stars, some of them with
discs, associated with the B-type members lying on the main sequence.
We interpret the region as an area of recent star formation with some
residual and very localized ongoing star formation. We do not find
evidence for sequential star formation on a large scale. The classical
definition of Aur OB2 has to be reconsidered, because its two main
open clusters, Stock 8 and NGC 1893, are not at the same distance.
Stock 8 is probably located in the Perseus arm, but other nearby HII
regions whose distances also place them in this arm show quite
different distances and radial velocities and, therefore, are not
connected.
Description:
We present tables with coordinates in J2000, near IR photometry and
Stromgren photometry for stars in the open cluster Stock 8 and in the
two new open clusters: Alicante 11 and Alicante 12
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
tablea1.dat 72 163 Coordinates in J2000 and 2MASS photometry for
stars in the cluster Stock 8
tablea2.dat 66 589 Near IR photometry taken by us for stars in the
cluster Stock 8
tablea3.dat 80 163 Stromgren photometry for stars in the cluster
Stock 8
tablea4.dat 76 57 Coordinates in J2000 and 2MASS photometry for
stars in the new cluster Alicante 11
tablea5.dat 82 57 Stromgren photometry for stars in the new
cluster Alicante 11
tablea6.dat 76 52 Coordinates in J2000 and 2MASS photometry for
stars in the new cluster Alicante 12
tablea7.dat 82 52 Stromgren photometry for stars in the new
cluster Alicante 12
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Byte-by-byte Description of file: tablea1.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- --- [ST]
3- 5 I3 --- ST Identification of the star with optical
photometry in the cluster Stock 8
7- 9 I3 --- STIR ? The identification of the star with our
near IR photometry in the cluster Stock 8 (1)
11- 12 I2 h RAh Right ascension (J2000)
14- 15 I2 min RAm Right ascension (J2000)
17- 21 F5.2 s RAs Right ascension (J2000)
23 A1 --- DE- Declination sign (J2000)
24- 25 I2 deg DEd Declination (J2000)
27- 28 I2 arcmin DEm Declination (J2000)
30- 33 F4.1 arcsec DEs Declination (J2000)
35- 40 F6.3 mag Jmag ?=- 2MASS J magnitude (2)
42- 46 F5.3 mag e_Jmag ?=- rms uncertainty on Jmag (2)
48- 53 F6.3 mag Hmag ?=- 2MASS H magnitude (2)
55- 59 F5.3 mag e_Hmag ?=- rms uncertainty on Hmag (2)
61- 66 F6.3 mag Ksmag ?=- 2MASS Ks magnitude (2)
68- 72 F5.3 mag e_Ksmag ?=- rms uncertainty on Ksmag (2)
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Note (1): This nomenclature is the number of the star in tablea2.dat
corresponding to our Near IR photometry deeper than 2MASS photometry.
Note (2): The 2MASS photometry values are given for stars with no measurement
obtained by us in tablea2.dat.
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Byte-by-byte Description of file: tablea2.dat
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Bytes Format Units Label Explanations
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1- 3 I3 --- STIR The identification of the star with our near
IR photometry in the cluster Stock 8
5- 6 I2 h RAh Right ascension (J2000)
8- 9 I2 min RAm Right ascension (J2000)
11- 15 F5.2 s RAs Right ascension (J2000)
17 A1 --- DE- Declination sign (J2000)
18- 19 I2 deg DEd Declination (J2000)
21- 22 I2 arcmin DEm Declination (J2000)
24- 27 F4.1 arcsec DEs Declination (J2000)
29- 34 F6.3 mag Jmag J magnitude (1)
36- 40 F5.3 mag e_Jmag rms uncertainty on Jmag (1)
42- 47 F6.3 mag Hmag H magnitude (1)
49- 53 F5.3 mag e_Hmag rms uncertainty on Hmag (1)
55- 60 F6.3 mag Ksmag Ks magnitude (1)
62- 66 F5.3 mag e_Ksmag rms uncertainty on Ksmag (1)
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Note (1): Near-IR photometry obtained by us for stars in the cluster Stock8.
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Byte-by-byte Description of file: tablea3.dat
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Bytes Format Units Label Explanations
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1- 2 A2 --- --- [ST]
3- 5 I3 --- ST The identification of the star with optical
photometry in the cluster Stock8
7- 12 F6.3 mag Vmag V-band magnitude
14- 18 F5.3 mag e_Vmag rms uncertainty on Vmag
19 A1 --- n_Vmag [*] Note on Vmag (G1)
21- 25 F5.3 mag b-y Stromgren b-y colour index
27- 31 F5.3 mag e_b-y rms uncertainty on b-y
32 A1 --- n_b-y [*] Note on b-y (G1)
34- 39 F6.3 mag c1 Stromgren c1 index
41- 45 F5.3 mag e_c1 rms uncertainty on c1
46 A1 --- n_c1 [*] Note on c1 (G1)
48 I1 --- o_Vmag Number of measurements for V, b-y and c1
50- 55 F6.3 mag m1 Stromgren m1 index
57- 61 F5.3 mag e_m1 rms uncertainty on m1
62 A1 --- n_m1 [*] Note on m1 (G1)
64 I1 --- o_m1 Number of measurements for m1
66- 70 F5.3 mag beta ?=- beta index
72- 76 F5.3 mag e_beta ?=- rms uncertainty on beta index
77 A1 --- n_beta [*] Note on beta (G1)
80 I1 --- o_beta Number of measurements for beta
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Byte-by-byte Description of file: tablea4.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- --- [Alicante11-]
12- 13 I2 --- Alicante11 The identification of the star with optical
photometry in the cluster Alicante 11
15- 16 I2 h RAh Right ascension (J2000)
18- 19 I2 min RAm Right ascension (J2000)
21- 25 F5.2 s RAs Right ascension (J2000)
27 A1 --- DE- Declination sign (J2000)
28- 29 I2 deg DEd Declination (J2000)
31- 32 I2 arcmin DEm Declination (J2000)
34- 37 F4.1 arcsec DEs Declination (J2000)
39- 44 F6.3 mag Jmag ?=- 2MASS J magnitude
46- 50 F5.3 mag e_Jmag ?=- rms uncertainty on Jmag
52- 57 F6.3 mag Hmag ?=- 2MASS H magnitude
59- 63 F5.3 mag e_Hmag ?=- rms uncertainty on Hmag
65- 70 F6.3 mag Ksmag ?=- 2MASS Ks magnitude
72- 76 F5.3 mag e_Ksmag ?=- rms uncertainty on Ksmag
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Byte-by-byte Description of file: tablea5.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- --- [Alicante11-]
12- 13 I2 --- Alicante11 The identification of the star with optical
photometry in the cluster Alicante 11
15- 20 F6.3 mag Vmag V-band magnitude
22- 26 F5.3 mag e_Vmag rms uncertainty on Vmag
28- 32 F5.3 mag b-y Stromgren b-y colour index
34- 38 F5.3 mag e_b-y rms uncertainty on b-y
39 A1 --- n_b-y [*] Note on b-y (G1)
40- 45 F6.3 mag m1 Stromgren m1 index
48- 52 F5.3 mag e_m1 rms uncertainty on m1
53 A1 --- n_m1 [*] Note on m1 (G1)
54- 59 F6.3 mag c1 Stromgren c1 index
62- 66 F5.3 mag e_c1 rms uncertainty on c1
67 A1 --- n_c1 [*] Note on c1 (G1)
69- 73 F5.3 mag beta beta index
75- 79 F5.3 mag e_beta rms uncertainty on beta index
80 A1 --- n_beta [*] Note on beta (G1)
82 I1 --- o_Vmag Number of measurements for each magnitude,
colour and index
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Byte-by-byte Description of file: tablea6.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 11 A11 --- --- [Alicante12-]
12- 13 I2 --- Alicante12 The identification of the star with optical
photometry in the cluster Alicante 12
15- 16 I2 h RAh Right ascension (J2000)
18- 19 I2 min RAm Right ascension (J2000)
21- 25 F5.2 s RAs Right ascension (J2000)
27 A1 --- DE- Declination sign (J2000)
28- 29 I2 deg DEd Declination (J2000)
31- 32 I2 arcmin DEm Declination (J2000)
34- 37 F4.1 arcsec DEs Declination (J2000)
39- 44 F6.3 mag Jmag 2MASS J magnitude
46- 50 F5.3 mag e_Jmag ?=- rms uncertainty on Jmag
52- 57 F6.3 mag Hmag 2MASS H magnitude
59- 63 F5.3 mag e_Hmag ?=- rms uncertainty on Hmag
65- 70 F6.3 mag Ksmag 2MASS Ks magnitude
72- 76 F5.3 mag e_Ksmag rms uncertainty on Ksmag
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Byte-by-byte Description of file: tablea7.dat
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Bytes Format Units Label Explanations
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1- 11 A11 --- --- [Alicante12-]
12- 13 I2 --- Alicante12 The identification of the star with optical
photometry in the cluster Alicante 12
15- 20 F6.3 mag Vmag V-band magnitude
22- 26 F5.3 mag e_Vmag rms uncertainty on Vmag
28- 32 F5.3 mag b-y Stromgren b-y colour index
34- 38 F5.3 mag e_b-y rms uncertainty on b-y
39 A1 --- n_b-y [*] Note on b-y (G1)
41- 46 F6.3 mag m1 Stromgren m1 index
48- 52 F5.3 mag e_m1 rms uncertainty on m1
53 A1 --- n_m1 [*] Note on m1 (G1)
55- 60 F6.3 mag c1 Stromgren c1 index
62- 66 F5.3 mag e_c1 rms uncertainty on c1
67 A1 --- n_c1 [*] Note on c1 (G1)
69- 73 F5.3 mag beta beta index
75- 79 F5.3 mag e_beta rms uncertainty on beta index
80 A1 --- n_beta [*] Note on beta (G1)
82 I1 --- o_Vmag Number of measurements for each magnitude,
colour and index
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Global notes:
Note (G1): The values with label '*' are not considered in the analysis because
their photometric errors are around 0.1. The error assigned is the standard
deviation for stars with more than one measurement and the photometric errors
from DAOPHOT for stars with only one measurement, with the errors in the colour
indices calculated through error propagation.
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Acknowledgements:
Amparo Marco, amparo.marco(at)ua.es
(End) Patricia Vannier [CDS] 31-May-2016