2017A&A...602A.109S


C.D.S. - SIMBAD4 rel 1.7 - 2021.02.24CET21:54:34

2017A&A...602A.109S - Astronomy and Astrophysics, volume 602A, 109-109 (2017/6-1)

A dynamo mechanism as the potential origin of the long cycle in double periodic variables.

SCHLEICHER D.R.G. and MENNICKENT R.E.

Abstract (from CDS):

The class of double period variables (DPVs) consists of close interacting binaries, with a characteristic long period that is an order of magnitude longer than the corresponding orbital period, many of them with a characteristic ratio of approximately 35. We consider here the possibility that the accretion flow is modulated as a result of a magnetic dynamo cycle. Due to the short binary separations, we expect the rotation of the donor star to be synchronized with the rotation of the binary due to tidal locking. We here present a model to estimate the dynamo number and the resulting relation between the activity cycle length and the orbital period, as well as an estimate for the modulation of the mass transfer rate. The latter is based on Applegate's scenario, implying cyclic changes in the radius of the donor star and thus in the mass transfer rate as a result of magnetic activity. Our model is applied to a sample of 17 systems with known physical parameters, 11 of which also have known modulation periods. In spite of the uncertainties of our simplified framework, the results show a reasonable agreement, indicating that a dynamo interpretation is potentially feasible. At the same time, we note that the orbital period variations resulting from Applegate's model are sufficiently small to be consistent with the data. We conclude that both larger samples with known physical parameters as well as potential direct probes of the magnetism of the donor star, including cold spots as well as polarization, will be valuable to further constrain the nature of these systems.

Abstract Copyright: © ESO, 2017

Journal keyword(s): binaries close - stars: variables: general - stars: activity - dynamo - dynamo

Simbad objects: 28

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Number of rows : 28

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 HD 232121 Al* 00 10 42.0679098681 +54 53 29.360355721   9.67 8.97     B5+K3III 175 0
2 V* U Cep Al* 01 02 18.4416064122 +81 52 32.080928443   6.92 6.92     G2III:+B8/9 461 0
3 NAME Magellanic Clouds GrG 03 00 -71.0           ~ 5854 1
4 V* RX Cas bL* 03 07 45.7481570255 +67 34 38.614798549   10.14 8.64     K1III+A5eIII 175 0
5 * bet Per EB* 03 08 10.1324535 +40 57 20.328013 1.70 2.07 2.12 2.08 2.11 B8V 1159 2
6 V* V471 Tau EB* 03 50 24.9664598642 +17 14 47.433240686   10.258 9.373   8.393 K2V+DA 621 0
7 OGLE LMC-SC8 125836 EB* 05 15 53.21 -69 25 57.9   15.74 15.414 15.71 15.374 ~ 22 0
8 SV* HV 936 EB* 05 20 03.9485446147 -69 36 39.062393141     14.800 14.81 14.717 ~ 9 0
9 NAME LMC G 05 23 34.6 -69 45 22     0.4     ~ 15187 1
10 HD 50846 Al* 06 54 54.7083961175 -01 22 32.849416553   8.46 8.43     B5/7Ib 138 0
11 V* BR CMi a2* 07 38 50.9829375551 +07 57 59.645337369   7.36 7.15     B9.5+G8III 25 0
12 V* UX Mon Al* 07 59 16.3751282592 -07 30 17.889948033   8.74 8.42     A2/3+G/K 126 0
13 V* DQ Vel Al* 09 30 34.2074813756 -50 11 54.064561384   11.38 10.92     G4V+G4V 20 0
14 V* W UMa EB* 09 43 45.4704899627 +55 57 09.066718574   8.54 7.75     G2Vn 637 1
15 V* TT Hya Al* 11 13 12.4975968306 -26 27 54.251048400   7.43 7.31     F0IV:kA2mA3:_sh 177 0
16 V* DP Leo CV* 11 17 15.9238061197 +17 57 41.680410866           ~ 213 1
17 CD-55 4911 Al* 13 01 34.8172584672 -56 05 30.905970910   10.47 9.95     Be 23 0
18 V* QS Vir EB* 13 49 52.0031855330 -13 13 37.001934702 14.27 14.98 14.40 14.37   DA3+dM 123 1
19 V* LP Ara bL* 16 40 01.7836288870 -46 39 34.856152016   10.48 10.21     B8 17 0
20 V* V393 Sco Al* 17 48 47.6025530213 -35 03 25.628506169   7.71 7.59     B3III 60 0
21 V* W Ser Al* 18 09 50.6487890730 -15 33 00.269169421   9.64 8.42     F8/G2Iaep(+A) 130 0
22 HD 170582 bL* 18 30 47.5278321859 -14 47 27.817177399   10.07 9.66     A9V 13 0
23 V* BY Dra BY* 18 33 55.7719224141 +51 43 08.903033617 10.22 9.23   8.733   K4Ve+K7.5Ve 598 0
24 HD 174237 Be* 18 46 43.0889592280 +52 59 16.650319177 5.06 5.80 5.90     B3+F5III 195 0
25 OH 31.0 +0.0 OH* 18 47 41.13768 -01 45 11.4048           ~ 127 1
26 V* V448 Cyg bL* 20 06 09.9485954895 +35 23 09.614693894 7.89 8.45 8.16     O9.5V+B1Ib 144 0
27 * 14 Lac bL* 22 50 21.7772135639 +41 57 12.179527815 5.49 5.961 5.910     B4+F9III 140 0
28 NAME Galactic Bulge reg ~ ~           ~ 3531 0

    Equat.    Gal    SGal    Ecl

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2021.02.24-21:54:34

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