2019A&A...624A..32M


C.D.S. - SIMBAD4 rel 1.7 - 2021.06.13CEST16:24:08

2019A&A...624A..32M - Astronomy and Astrophysics, volume 624A, 32-32 (2019/4-1)

Variation of the magnetic field of the Ap star HD 50169 over its 29-year rotation period.

MATHYS G., ROMANYUK I.I., HUBRIG S., KUDRYAVTSEV D.O., LANDSTREET J.D., SCHOLLER M., SEMENKO E.A. and YAKUNIN I.A.

Abstract (from CDS):


Context. The Ap stars that rotate extremely slowly, with periods of decades to centuries, represent one of the keys to the understanding of the processes leading to the differentiation of stellar rotation.
Aims. We characterise the variations of the magnetic field of the Ap star HD 50169 and derive constraints about its structure.
Methods. We combined published measurements of the mean longitudinal field <Bz> of HD 50169 with new determinations of this field moment from circular spectropolarimetry obtained at the 6m telescope BTA of the Special Astrophysical Observatory of the Russian Academy of Sciences. For the mean magnetic field modulus <B>, literature data were complemented by the analysis of ESO spectra, both newly acquired and from the archive. Radial velocities were also obtained from these spectra.
Results. We present the first determination of the rotation period of HD 50169, Prot=29.04±0.82yr. HD 50169 is currently the longest-period Ap star for which magnetic field measurements have been obtained over more than a full cycle. The variation curves of both <Bz> and <B> have a significant degree of anharmonicity, and there is a definite phase shift between their respective extrema. We confirm that HD 50169 is a wide spectroscopic binary, refine its orbital elements, and suggest that the secondary is probably a dwarf star of spectral type M.
Conclusions. The shapes and mutual phase shifts of the derived magnetic variation curves unquestionably indicate that the magnetic field of HD 50169 is not symmetric about an axis passing through its centre. Overall, HD 50169 appears similar to the bulk of the long-period Ap stars.

Abstract Copyright: © ESO 2019

Journal keyword(s): stars: individual: HD 50169 - stars: chemically peculiar - stars: rotation - stars: magnetic field - binaries: spectroscopic

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 - 2021
#notes
1 V* GR And a2* 00 28 28.5693545697 +32 26 15.879131266   6.99 6.91     A5VpSiSrCr 136 0
2 V* GY And a2* 01 38 31.8241484792 +45 23 58.950612500   6.343 6.380     A2:VpSiSrCrEu 245 0
3 HD 12288 a2* 02 03 30.5093779864 +69 34 56.260586887   7.83 7.74     A0pCrSi 98 0
4 HD 18078 a2* 02 56 32.0100802361 +56 10 41.427097237   8.50 8.27     ~ 82 0
5 HD 50169 Em* 06 51 59.2282603066 -01 38 40.393959773   9.01 8.98     ApEuSrCr 90 0
6 V* V827 Mon a2* 07 29 35.4522068599 -09 15 33.315319853   8.40 7.94     A6IIIpSr 63 0
7 * 53 Cam a2* 08 01 42.4313674994 +60 19 27.801603076   6.177 6.008     A3VpSrSiCrEu 385 0
8 V* KQ Vel a2* 10 55 01.0018015910 -42 15 04.062281118 5.78 6.03 6.11     Ap(SiCr) 124 0
9 V* V816 Cen dS* 11 37 37.0411005456 -46 42 34.875395453 8.99 8.79 8.03     F8/G0p 300 0
10 * alf02 CVn a2* 12 56 01.6662171 +38 19 06.154110 2.44 2.76 2.88 2.98 3.05 A0VpSiEu 648 0
11 * o Vir a2* 13 34 07.9318557 +03 39 32.273821 4.96 4.96 4.94 4.86 4.89 ApEuCrSr 324 0
12 V* CS Vir a2* 14 18 38.2580290341 -18 42 57.482173097 5.86 5.90 5.90     ApSi(Cr) 304 0
13 * 33 Lib a2* 15 29 34.7422042672 -17 26 27.375775287 7.22 7.07 6.69     F0VspEuGdSr 240 0
14 V* V3961 Sgr a2* 19 51 50.6105485243 -39 52 27.724256879 5.05 5.27 5.33     ApCr(Si) 174 0
15 V* V1291 Aql a2* 19 53 18.7357390150 -03 06 52.065320660   5.837 5.619     F0VpSrCrEu 263 0
16 V* V1372 Cyg a2* 20 13 36.3256530372 +53 39 33.549163874   7.334 7.333     A4p 123 0
17 HD 200405 SB* 21 01 38.2996945581 +47 54 47.267062295   8.98 8.90     A0pSrCr 36 0
18 * gam Equ a2* 21 10 20.5001160337 +10 07 53.682085548 5.03 4.94 4.68 4.43 4.32 A9VpSrCrEu 522 0

    Equat.    Gal    SGal    Ecl

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