J/AJ/150/16 Speckle-interferometry in Melotte 111 (Guerrero+, 2015)
Stellar multiplicity of the open cluster Melotte 111.
Guerrero C.A., Orlov V.G., Monroy-Rodriguez M.A., Borges Fernandes M.
<Astron. J., 150, 16 (2015)>
=2015AJ....150...16G 2015AJ....150...16G (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open ; Interferometry ; Stars, double and multiple ;
Cross identifications ; Photometry, RI
Keywords: binaries: close - techniques: interferometric -
open clusters and associations: individual: Melotte 111
Abstract:
We present a high-angular resolution survey for the search of binary
and multiple stars in the Galactic open cluster Melotte 111. Combining
our own speckle-interferometric observations with data taken from the
literature, we found a ratio of the number of single to multiple stars
to be 29:8:0:0:0:1 for the most probable members, indicating a
multiplicity fraction for this cluster of 25.6%±2%. We also observed
field stars in the vicinity of the cluster and estimated a ratio of
multiplicities of 286:17:1:0:0:0:1 (between one and seven companions),
equivalent to a multiplicity fraction of 5.9%±3%. We showed that the
cumulative distribution of separations for our sample stars is in
agreement with Opik's law.
Description:
Using speckle-interferometry we have initiated a survey of binary
stars and multiple systems in Galactic open clusters. In this article,
we continued our survey with the open cluster Melotte 111. We observed
168 stars among most probable, probable, and possible members of
Melotte 111, over the 8° diameter of the cluster. We separated the
previously known binary stars into two groups: binaries cataloged in
the Washington Double Star (WDS) Catalog (cat. B/wds) in Table1 and
spectroscopic binaries (Table2) reported in the literature.
We obtained our speckle-interferometric data during one observing run
at the 2.1m telescope of the Observatorio Astronomico Nacional (OAN),
Mexico. The diffraction-limited resolution of the 2.1m telescope is
0.07'', for λ=640nm. We performed the observations using the
EMCCD iXon 885 DU from Andor Technology. This is a low noise, high
sensitive EMCCD camera. The CCD has 1004*1002 pixels of 8µm. During
seven nights, from 2014 April 12 to 18, we used the f/7.5 secondary
mirror, combined with a micro objective, which together provides a
scale of 18.5mas/pixel after calibration, corresponding to a visual
field of 16.65''*16.65'' for the total area of the detector. We
observed a total of 343 stars distributed over sky area with 8°
diameter of Melotte 111. We observed every object using the R
Johnson-Cousins filter. We estimated that the seeing was between 0.6''
and 0.9'' for the whole run and aberrations introduced by the
telescope had similar values. As a result, long exposure images have a
resolution of about 1.5'' and the mean error in the companion
separation is 0.013'' and 1° in the position angle, modulo
180°.
For the whole sample, we were able to resolve systems as close as
0.35'' and detect pairs as wide as 8.91'' in some directions. We
detected speckle-interferometric companions for nine of the stars in
our sample. Table3 contains the results of our measurements.
During data processing, we noted that the data obtained using the
EMCCD showed a good photometric stability. Photometric measurements
were not the initial goal of this publication, so we did not observed
standard stars. However, in the literature we found information about
flux in the R band for 71 of our sample stars, excluding intrinsic
variable stars, which allowed us to perform a flux calibration for our
data. We present the photometric results in Table4, in which we
excluded all binary stars.
File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 59 24 Known stellar multiplicity
table2.dat 93 11 Known spectroscopic binaries
table3.dat 49 10 Speckle measurements
table4.dat 42 311 R photometry
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See also:
B/wds : The Washington Visual Double Star Catalog (Mason+ 2001-2014)
I/280 : All-sky Compiled Catalogue of 2.5 million stars (Kharchenko+ 2009)
I/239 : The Hipparcos and Tycho Catalogues (ESA 1997)
J/AJ/141/45 : Speckel observations of HIP stars (Horch+, 2011)
J/A+A/491/951 : Positions and cross-references in Coma Ber (Mermilliod+ 2008)
J/A+A/438/1163 : Catalogue of Open Cluster Data (COCD) (Kharchenko+, 2005)
J/AN/325/740 : Astrophysical supplements to ASCC-2.5 (Kharchenko+, 2004)
Byte-by-byte Description of file: table1.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- ASCC [684431/778904] Star number in the ASCC-2.5 catalog
(Kharchenko et al. 2009, cat. I/280)
8 A1 --- f_ASCC [abc] Melotte 111 membership flag (G1)
10- 19 A10 --- WDS WDS identification (HHMMS+DDMM, J2000)
21- 22 A2 --- Comp Component
24- 30 A7 --- Disc Discoverer designation adopted by the WDS
32- 34 I3 deg PA [16/328] Measured Position Angle
36- 40 F5.1 arcsec Sep [0.3/447.5] Angular separation
42- 45 F4.2 mag Dmag [0.09/8.47] The companion magnitude difference
47- 52 F6.4 --- Pkin [0/1] Proper motion membership probability (G2)
54- 59 F6.4 --- Pphot [0/1] Membership probability from photometry (G2)
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Byte-by-byte Description of file: table2.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- ASCC [684793/778870] Star number in the ASCC-2.5 catalog
(Kharchenko et al. 2009, cat. I/280)
8 A1 --- f_ASCC [ac] Melotte 111 membership flag (G1)
10- 17 A8 --- BD BD identifier
19- 24 I6 --- HD [107067/109307]? HD identifier
26- 30 I5 --- HIP [60025/61295]? Hipparcos identifier (cat. I/239)
32- 35 A4 --- SB Spectroscopic binarity (SB1, SB10, SB2O) (1)
37- 42 F6.4 --- Pkin [0/1] Proper motion membership probability (G2)
44- 49 F6.4 --- Pphot [0.6/1] Membership probability from photometry (G2)
51- 93 A43 --- Ref Reference for the orbital parameters
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Note (1): The codes for the spectroscopic binarity is defined as below:
SB1 = Single lined spectroscopic binary;
SB2 = Double lined spectroscopic binary;
SB0 = Spectroscopic binary with orbital parameters calculated;
SB = Spectroscopic binary without calculated orbit.
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Byte-by-byte Description of file: table3.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- ASCC [684740/778981] Star number in the ASCC-2.5 catalog
(Kharchenko et al. 2009, cat. I/280)
8 A1 --- f_ASCC [a] Melotte 111 membership flag (G1)
10- 16 A7 --- Disc Discoverer designation adopted by the WDS
18- 26 F9.4 yr Date Epoch of the observation in fractional Besselian
years
28- 30 I3 deg PA [11/167]? Measured Position Angle
32- 35 F4.2 arcsec Sep [0.35/8.91]? Angular separation
37- 42 F6.4 --- Pkin [0/0.36] Membership probability from proper
motion (G2)
44- 49 F6.4 --- Pphot [0/1] Membership probability from photometry (G2)
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Byte-by-byte Description of file: table4.dat
--------------------------------------------------------------------------------
Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 6 I6 --- ASCC [684360/779035] Star number in the ASCC-2.5 catalog
(Kharchenko et al. 2009, cat. I/280)
8 A1 --- f_ASCC [abc] Melotte 111 membership flag (G1)
10- 15 F6.3 mag Bmag [5.071/14.651] The B-band magnitude (1)
17- 22 F6.3 mag Vmag [4.339/13.748] The V-band magnitude (1)
24- 28 F5.2 mag Rmag [3.58/13.36] The R-band magnitude that we estimated
30- 35 F6.4 --- Pkin [0/1] Proper motion membership probability (G2)
37- 42 F6.4 --- Pphot [0/1] Membership probability from photometry (G2)
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Note (1): Taken from the ASCC-2.5 catalog (Kharchenko et al. 2009, cat. I/280).
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Global Notes:
Note (G1): The membership flags are defined as follows:
a = Most probable member star of the open cluster Melotte 111;
b = Probable member star of the open cluster Melotte 111;
c = Possible member star of the open cluster Melotte 111.
Note (G2): Taken from Kharchenko et al. 2004 (cat. J/AN/325/740).
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History:
From electronic version of the journal
(End) Sylvain Guehenneux [CDS] 26-Oct-2015