J/A+A/630/A119 Gaia DR2 distances to two clusters (Maiz Apellaniz, 2019)
Gaia DR2 distances to Collinder 419 and NGC 2264 and new astrometric orbits for
HD 193322 Aa,Ab and 15 Mon Aa,Ab.
Maiz Apellaniz J.
<Astron. Astrophys. 630, A119 (2019)>
=2019A&A...630A.119M 2019A&A...630A.119M (SIMBAD/NED BibCode)
ADC_Keywords: Clusters, open; Parallaxes, trigonometric; Photometry, G band;
Spectral types; Stars, OB
Keywords: astrometry - binaries: visual - methods: data analysis -
open clusters and associations: individual: Collinder 419 -
open clusters and associations: individual: NGC 2264 -
stars: kinematics and dynamics -
Abstract:
On the one hand, the second data release of the Gaia mission (GaiaDR2,
Cat. I/345) has opened a trove of astrometric and photometric data for
Galactic clusters within a few kpc of the Sun. On the other hand,
lucky imaging has been an operational technique to measure the relative
positions of visual binary systems for a decade and a half, a time
sufficient to apply its results to the calculation of orbits of some
massive multiple systems within ∼1kpc of the Sun.
As part of an ambitious research program to measure distances to
Galactic stellar groups (including clusters) containing O stars,I
start with two of the nearest examples: Collinder 419 in Cygnus and
NGC 2264 in Monoceros. The main ionizing source for both clusters is a
multiple system with an O-type primary: HD 193322 and 15 Mon,
respectively. For each of those two multiple systemsI aim to derive
new astrometric orbits for the Aa,Ab components.
First, I present a method that usesGaiaDR2 G+GBP+GRP photometry,
positions, proper motions, and parallaxes to obtain the membership and
distance of a stellar group and apply it to Collinder 419 and
NGC 2264. Second, I present a new code that calculates astrometric
orbits by searching the whole seven-parameter orbit space and apply it
to HD 193 322 Aa,Ab and 15 Mon Aa,Abusing as input literature data
from the Washington Double Star Catalog (WDS) and the AstraLux
measurements recently presented by Maiz Apellaniz et al. (2019,
Cat. J/A+A/626/A20)
I obtain GaiaDR2 distances of 1006+37-34pc for Collinder 419 and
719±16pc for NGC 2264, with the main contribution to the
uncertainties coming from the spatial covariance of the parallaxes.
The two NGC 2264 subclusters are at the same distance (within the
uncertainties) and they show a significant relative proper motion. The
distances are shown to be robust. HD 193322 Aa,Ab follows an eccentric
(e=0.58+0.03-0.04) orbit with a period of 44±1 a and the three
stars it contains have a total mass of 76.1+9.9-7.4M☉. The
orbit of 15 Mon Aa,Ab is even more eccentric
(e=0.770+0.023-0.030), with a period of 108±12 a and a total
mass of 45.1+3.6-3.3M☉ for its two stars.
Description:
File table8.dat gives the Gaia-DR2-selected cluster membership for
Collinder 419. File table9.dat gives the Gaia-DR2-selected cluster
membership for NGC 2264.
Objects:
-------------------------------------------------------
RA (2000) DE Designation(s)
-------------------------------------------------------
20 18 07 +40 43.9 Collinder 419 = Cl Collinder 419
06 40 58 +09 53.7 NGC 2264 = NGC 2264
-------------------------------------------------------
File Summary:
--------------------------------------------------------------------------------
FileName Lrecl Records Explanations
--------------------------------------------------------------------------------
ReadMe 80 . This file
table8.dat 153 93 Collinder 419 members
table9.dat 155 340 NGC 2264 members
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See also:
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
II/246 : 2MASS All-Sky Catalog of Point Sources (Cutri+ 2003)
J/A+A/626/A20 : MONOS. I. Spectral classifications (Maiz Apellaniz+, 2019)
Byte-by-byte Description of file: table8.dat table9.dat
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Bytes Format Units Label Explanations
--------------------------------------------------------------------------------
1- 23 A23 --- Name Object name for cluster stars
25- 43 I19 --- GaiaDR2 Gaia DR2 ID
45- 61 A17 --- 2MASS 2MASS ID (JHHMMSSss+DDMMSSs)
63- 68 F6.4 mas Plx Gaia DR2 parallax
70- 75 F6.4 mas e_Plx Gaia DR2 parallax uncertainty
77- 82 F6.3 mas/a pmRA* Gaia DR2 proper motion in RA, pmRA*cosDE
84- 88 F5.3 mas/a e_pmRA* Gaia DR2 proper motion in RA uncertainty
90- 95 F6.3 mas/a pmDE Gaia DR2 proper motion in dec
97-101 F5.3 mas/a e_pmDE Gaia DR2 proper motion in dec uncertainty
103-109 F7.4 mag Gmag Gaia DR2 G magnitude
111-116 F6.4 mag e_Gmag Gaia DR2 G magnitude uncertainty
118-124 F7.4 mag BPmag Gaia DR2 BP-RP color
126-131 F6.4 mag e_BPmag Gaia DR2 BP-RP color uncertainty
133-151 A19 --- SpType Spectral type
153 A1 --- r_SpType [GS-] Spectral type source: G(OSSS) or S(imbad)
155 A1 --- subcm [NS-] Subcluster membership: N(orth) or S(outh,
for table9.dat only
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Acknowledgements:
Jesus Maiz Appellaniz, jmaiz(at)cab.inta-csic.es
(End) Patricia Vannier [CDS] 09-Aug-2019