2017A&A...602A..57A


C.D.S. - SIMBAD4 rel 1.7 - 2020.04.09CEST16:52:53

2017A&A...602A..57A - Astronomy and Astrophysics, volume 602A, 57-57 (2017/6-1)

Young, active radio stars in the AB Doradus moving group.

AZULAY R., GUIRADO J.C., MARCAIDE J.M., MARTI-VIDAL I., ROS E., TOGNELLI E., HORMUTH F. and ORTIZ J.L.

Abstract (from CDS):

Context. Precise determination of stellar masses is necessary to test the validity of pre-main-sequence (PMS) stellar evolutionary models, whose predictions are in disagreement with measurements for masses below 1.2M. To improve such a test, and based on our previous studies, we selected the AB Doradus moving group (AB Dor-MG) as the best-suited association on which to apply radio-based high-precision astrometric techniques to study binary systems.
Aims. We seek to determine precise estimates of the masses of a set of stars belonging to the AB Dor-MG using radio and infrared observations.
Methods. We observed in phase-reference mode with the Very Large Array (VLA) at 5GHz and with the European VLBI Network (EVN) at 8.4GHz the stars HD 160934, EK Dra, PW And, and LO Peg. We also observed some of these stars with the near-infrared CCD AstraLux camera at the Calar Alto observatory to complement the radio observations.
Results. We determine model-independent dynamical masses of both components of the star HD 160934, A and c, which are 0.70±0.07M and 0.45±0.04M, respectively. We revised the orbital parameters of EK Dra and we determine a sum of the masses of the system of 1.38±0.08M. We also explored the binarity of the stars LO Peg and PW And.
Conclusions. We found observational evidence that PMS evolutionary models underpredict the mass of PMS stars by 10%-40%, as previously reported by other authors. We also inferred that the origin of the radio emission must be similar in all observed stars, that is, extreme magnetic activity of the stellar corona that triggers gyrosynchrotron emission from non-thermal, accelerated electrons.

Abstract Copyright: © ESO, 2017

Journal keyword(s): binaries: general - stars: pre-main sequence - radio continuum: general - astrometry - astrometry

Status at CDS:  

Simbad objects: 18

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Number of rows : 18

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2020
#notes
1 3C 6 Rad 00 15 06.14740520 +32 16 13.3097781   18.0 16.8 15.61   ~ 26 1
2 V* PW And RS* 00 18 20.8896176716 +30 57 22.127515298   9.78 8.86 8.3 7.78 K2V 106 1
3 ICRF J002914.2+345632 AGN 00 29 14.24246572 +34 56 32.2471186   20.2       ~ 115 1
4 3C 48 QSO 01 37 41.2995845985 +33 09 35.079126038   16.62 16.20     ~ 2472 2
5 HD 36705B ** 05 28 44.4833327579 -65 26 46.034324029     13.0     M5+M5-6 87 0
6 HD 36705C * 05 28 44.83 -65 26 54.9           M8: 58 1
7 HD 36705 TT* 05 28 44.8916324761 -65 26 55.289846904 8.259 7.856 6.999 6.496 5.993 K0V 925 0
8 8C 1435+638 QSO 14 36 45.8021364767 +63 36 37.865982148   17.06 16.86 16.23   ~ 183 1
9 V* EK Dra BY* 14 39 00.2109485496 +64 17 29.977371998   8.243 7.604     G1.5V 373 0
10 NVSS J144158+631833 Rad 14 41 58.66928807 +63 18 33.4377902           ~ 8 1
11 SDSS J173838.64+611411.0 * 17 38 38.6673330179 +61 14 10.956775264           ~ 3 0
12 HD 160934B BD? 17 38 39.6 +61 14 16           M4 8 0
13 HD 160934 Fl* 17 38 39.6170537492 +61 14 16.102424643   11.34 10.15   8.99 K7Ve 90 0
14 8C 1745+624 QSO 17 46 14.03413721 +62 26 54.7383903   20.91 19.51     ~ 105 1
15 QSO J2115+295 QSO 21 15 29.41345556 +29 33 38.3669657     19.5 19.26   ~ 140 1
16 NVSS J212526+244203 Rad 21 25 26.17042529 +24 42 03.5791223           ~ 7 1
17 BD+22 4409 BY* 21 31 01.7141405072 +23 20 07.370852589   10.28 9.253 8.6 7.965 K3Vke 150 0
18 NAME AB Dor Moving Group MGr ~ ~           ~ 344 0

    Equat.    Gal    SGal    Ecl

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2020.04.09-16:52:53

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