J/ApJ/885/9 Triple system HD 28363; RVel and visual observations (Torres+, 2019)
Dynamical masses for the Triple system HD28363 in the Hyades Cluster.
Torres G., Stefanik R.P., Latham D.W.
<Astrophys. J., 885, 9 (2019)>
=2019ApJ...885....9T 2019ApJ...885....9T
ADC_Keywords: Stars, double and multiple; Spectra, optical; Radial velocities;
Keywords: Visual binary stars ; Open star clusters ; Spectroscopy ;
Space astrometry ; Stellar masses ; Fundamental parameters of stars ;
Main sequence stars ; Multiple stars ; Radial velocity
Abstract:
The star HD28363 in the Hyades cluster has been known for over a
century as a visual binary with a period of 40yr. The secondary is, in
turn, a single-lined spectroscopic binary with a 21day period. Here we
report extensive spectroscopic monitoring of this hierarchical triple
system that reveals the spectral lines of the third star for the first
time. Combined with astrometric information, this makes it possible to
determine the dynamical masses of all three stars. Only six other
binaries in the Hyades have had their individual component masses
determined dynamically. We infer the properties of the system by
combining our radial-velocity measurements with visual observations,
lunar occultation measurements, and with proper motions from the
Hipparcos and Gaia missions that provide a constraint on the
astrometric acceleration. We derive a mass of
1.341-0.024+0.026M☉ for the visual primary, and
1.210±0.021 and 0.781±0.014 M☉ for the other two stars.
These measurements along with those for the other six systems
establish an empirical mass-luminosity relation in the Hyades that is
in broad agreement with current models of stellar evolution for the
known age and chemical composition of the cluster.
Description:
Our spectroscopic monitoring of HD28363 at the Center for Astrophysics
(CfA), carried out as part of a large survey of the Hyades cluster,
began in 1980 November and continued until 2013 September.
Observations were gathered with four different instruments. Spectra
through 2007 November were made with the CfA Digital Speedometers (DS)
on the 1.5m Tillinghast reflector at the Fred L. Whipple Observatory
(Mount Hopkins, AZ), the 1.5m Wyeth reflector at the Oak Ridge
Observatory (in the town of Harvard, MA), now closed, and the 4.5m
equivalent Multiple Mirror Telescope (also on Mount Hopkins) before
its conversion to a monolithic 6.5m mirror. These echelle instruments
with a resolving power of R∼35000 were equipped with intensified
photon-counting Reticon detectors and recorded a single order 45Å
wide centered at 5187Å, featuring the MgIb triplet. An additional
28 spectra of higher quality were obtained using the Tillinghast
Reflector Echelle Spectrograph (TRES), a bench-mounted fiber-fed
echelle instrument attached to the 1.5m Tillinghast reflector, with a
resolving power of R∼44000. These spectra cover the wavelength range
3800-9100Å in 51 orders.
Since its discovery in 1904 the relative positions of HD28363
(angular separations, and position angles) have been measured
by visual observers about 130 times, not counting another dozen
occasions in which the pair was not resolved. The most recent
observation was obtained at the end of 2016. Measurements until about
1970 were made with filar micrometers, and most observations since
were made using the speckle interferometry technique. A listing of all
measurements was kindly provided to us by Brian Mason (U.S. Naval
Observatory), extracted from the Washington Double Star Catalog (WDS),
with the dates of observation having been uniformly converted from the
traditional Besselian years to Julian years.
Objects:
----------------------------------------------
RA (2000) DE Designation(s)
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04 28 59.75 +16 09 32.7 HD 28363 = HD 28363
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File Summary:
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FileName Lrecl Records Explanations
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ReadMe 80 . This file
table1.dat 61 169 CfA radial velocities for HD 28363
table2.dat 65 131 Visual observations of HD 28363
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See also:
B/wds : The Washington Visual Double Star Catalog (Mason+, 2001-2020)
I/337 : Gaia DR1 (Gaia Collaboration, 2016)
I/345 : Gaia DR2 (Gaia Collaboration, 2018)
J/A+A/341/121 : Visual binary orbits and masses (Soederhjelm 1999
J/AJ/124/1144 : Orbits of 171 single-lined spectroscopic binaries (Latham,2002)
J/AJ/132/111 : BV(RI)Cphotometry of 77 Hyades stars (Joner+, 2006)
J/A+A/498/949 : Velocities 1253 F-K dwarfs in open clusters (Mermilliod+, 2009)
J/ApJ/883/105 : PA & angular separation measurements of 80 Tau (Torres, 2019)
Byte-by-byte Description of file: table1.dat
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Bytes Format Units Label Explanations
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1- 10 F10.4 d HJD [44560/56559] Heliocentric Julian Date, JD-2400000
12- 16 F5.2 km/s RVelA [28.71/46.98] Radial velocity, component A
18- 21 F4.2 km/s e_RVelA [0.1/2.6] Uncertainty in RVel-A
23- 27 F5.2 km/s RVelBa [7.1/91.81] Radial velocity, component Ba
29- 32 F4.2 km/s e_RVelBa [0.09/1.9] Uncertainty in RVel-Ba
34- 39 F6.2 km/s RVelBb [-40.08/94.8]? Radial velocity, component Bb
41- 45 F5.2 km/s e_RVelBb [1.1/16.5]? Uncertainty in RVel-Bb
47- 53 F7.5 --- Phase-I [0.05/0.87] Inner Orbital phase
55- 61 F7.5 --- Phase-O [0.0007/1] Outer Orbital phase
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Byte-by-byte Description of file: table2.dat
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Bytes Format Units Label Explanations
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1- 9 F9.4 yr Date [1904/2017] Julian year
11- 16 F6.2 deg PA [68.8/275]? Position angle
18- 25 F8.6 arcsec e_PA [0.001/0.03]? Uncertainty in PA (1)
27- 31 F5.2 deg (OC)PA [-9.63/23.42]? Residual, Positional Angle
33- 37 F5.2 --- (OC)PA-n [-2.09/2.94]? Normalized Residual,
(O-C)PA/(e_PA/Sep)
39- 44 F6.4 arcsec Sep [0.07/0.49]? Separation
46- 51 F6.4 arcsec e_Sep [0.0002/0.06]? Uncertainty in Sep (1)
53- 59 F7.4 arcsec (OC)Sep [-0.11/0.1]? Residual, separation
61- 65 F5.2 --- (OC)Sep-n [-2.06/2.69]? Normalized Residual,
(O-C)Sep/(e_Sep)
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Note (1): The uncertainties listed in the table correspond to the e_Sep and
e_PA values given in the text multiplied by the error inflation factors,
fSep and fPA, reported in Section 4, and represent the final errors used
in the solution described there.
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History:
From electronic version of the journal
(End) Prepared by [AAS], Coralie Fix, 31-May-2021