2020A&A...641L...8O


C.D.S. - SIMBAD4 rel 1.7 - 2020.11.28CET21:20:50

2020A&A...641L...8O - Astronomy and Astrophysics, volume 641, L8-8 (2020/9-1)

Chandra X-ray study confirms that the magnetic standard Ap star KQ Vel hosts a neutron star companion.

OSKINOVA L.M., IGNACE R., LETO P. and POSTNOV K.A.

Abstract (from CDS):


Context. KQ Vel is a peculiar A0p star with a strong surface magnetic field of about 7.5kG. It has a slow rotational period of nearly 8 years. Bailey et al. (A&A, 575, A115) detected a binary companion of uncertain nature and suggested that it might be a neutron star or a black hole.
Aims. We analyze X-ray data obtained by the Chandra telescope to ascertain information about the stellar magnetic field and/or interaction between the star and its companion.
Methods. We confirm previous X-ray detections of KQ Vel with a relatively high X-ray luminosity of 2x1030erg/s. The X-ray spectra suggest the presence of hot gas at > 20 MK and, possibly, of a nonthermal component. The X-ray light curves are variable, but data with better quality are needed to determine a periodicity, if any.
Results. We interpret the X-ray spectra as a combination of two components: the nonthermal emission arising from the aurora on the A0p star, and the hot thermal plasma filling the extended shell that surrounds the "propelling" neutron star .
Conclusions. We explore various alternatives, but a hybrid model involving the stellar magnetosphere along with a hot shell around the propelling neutron star seems most plausible. We speculate that KQ Vel was originally a triple system and that the Ap star is a merger product. We conclude that KQ Vel is an intermediate-mass binary consisting of a strongly magnetic main-sequence star and a neutron star.

Abstract Copyright: © ESO 2020

Journal keyword(s): binaries: spectroscopic - stars: chemically peculiar - stars: individual: KQ Vel - X-rays: binaries - X-rays: individuals: KQ Vel - magnetic fields

Simbad objects: 7

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Number of rows : 7

N Identifier Otype ICRS (J2000)
RA
ICRS (J2000)
DEC
Mag U Mag B Mag V Mag R Mag I Sp type #ref
1850 - 2021
#notes
1 * 14 Aur dS* 05 15 24.3939839964 +32 41 15.363849904   5.217 5.000 6.45   A9V 188 0
2 V* IQ Aur a2* 05 19 00.0284977265 +33 44 54.237390018   5.201 5.371     A0p 272 0
3 * sig Gem RS* 07 43 18.7269793 +28 53 00.642191 6.38 5.41 4.29 3.37 2.79 K1IIIe 448 0
4 V* KQ Vel a2* 10 55 01.0018015910 -42 15 04.062281118 5.78 6.03 6.11     Ap(SiCr) 121 0
5 V* CU Vir a2* 14 12 15.8054758 +02 24 33.953395 4.46 4.90 5.02 5.10 5.23 ApSi 353 0
6 * rho Oph A * 16 25 35.1182364594 -23 26 49.827436721 4.3 5.22 5.05     B2/3V 394 0
7 HD 224085 RS* 23 55 04.0516465022 +28 38 01.248194500 8.88 8.20   6.9   K2+IVeFe-1 686 0

    Equat.    Gal    SGal    Ecl

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2020.11.28-21:20:50

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