Orbital period changes of the nova-like cataclysmic variable AC
Cancri: evidence of magnetic braking and an unseen companion

J 2007

Orbital period changes of the nova-like cataclysmic variable AC Cancri: evidence of magnetic braking and an unseen companion

QIAN, Shengbang, Z.-B. DAI, J.-J. HE, J. Z. YUAN, F. Y. XIANG et. al.

Základní údaje

Originální název

Orbital period changes of the nova-like cataclysmic variable AC Cancri: evidence of magnetic braking and an unseen companion

Název česky

Změny orbitální periody nově podobné kataklyzmické proměnné hvězdy AC Cancri: důkaz magnetického brždění a neviditelné složky

Autoři

QIAN, Shengbang (156 Čína), Z.-B. DAI (156 Čína), J.-J. HE (156 Čína), J. Z. YUAN (156 Čína), F. Y. XIANG (156 Čína) a Miloslav ZEJDA (203 Česká republika, garant)

Vydání

Astronomy and Astrophysics, 2007, 0004-6361

Další údaje

Jazyk

angličtina

Typ výsledku

Článek v odborném periodiku

Obor

10308 Astronomy

Stát vydavatele

Francie

Utajení

není předmětem státního či obchodního tajemství

Odkazy

URL

Impakt faktor

Impact factor: 4.259

Kód RIV

RIV/00216224:14310/07:00029084

Organizační jednotka

Přírodovědecká fakulta

UT WoS

000245686800021

Klíčová slova anglicky

nova; cataclysmic variables; eclipsing binaries;AC Cnc; evolution; mass loss

Štítky

AC Cnc, cataclysmic variables, Eclipsing Binaries, Evolution, mass loss, nova

Příznaky

Mezinárodní význam, Recenzováno

Změněno: 24. 6. 2009 13:07, doc. RNDr. Miloslav Zejda, Ph.D.

Anotace

ORIG CZ

V originále

Aims.The source AC Cnc is a nova-like cataclysmic variable containing a white-dwarf primary with a mass of 0.76 Mo and a K2-type secondary with a mass of 0.77 Mo. We intend to study its period changes and search for evidence of magnetic braking and unseen third body. Methods: The period changes were investigated based on the analysis of the O-C curve, which is formed by one new eclipse time together with the others compiled from the literature. Results: A cyclic change with a period of 16.2 yr was found to be superimposed on a long-term period decrease at a rate of dot{P}=-1.24(0.44).{10-8} days/year. Conclusions: It is shown that the mechanism of magnetic activity-driven changes in the quadrupole momentum of the secondary star (Applegate's mechanism) does not explain it easily. This period oscillation was plausibly interpreted by a light-travel time effect caused by the presence of a cool M-type dwarf companion (M_3<0.097 Mo) in a long orbit (16.2 yr) around the binary. Since the masses of both components are nearly the same, the mass transfer from the lobe-filling secondary to the primary is not efficient to cause the continuous period decrease. It may be strong evidence of an enhanced magnetic stellar wind from the K2-type component. If the Alfén radius of the cool secondary is the same as that of the Sun (i.e., RA = 15 Ro), the mass-loss rate should be dot{M_2}=-1.65.{10-10} Mo/year. By using the enhanced mass loss proposed by Tout and Eggleton (1988), the mass-loss rate should be dot{M_2}=-1.18.{10-9} Mo/year. In this case, the Alfén radius is determined to be RA = 5.2 Ro. However, the long-term decrease of the period may be only a part of a long-period (<100 yr) oscillation caused by the presence of an additional body. To check the conclusions, new precise times of light minimum will be required.

Česky

Změny orbitální periody nově podobné kataklyzmické proměnné hvězdy AC Cancri: důkaz magnetického brždění a neviditelné složky

Návaznosti

GA205/04/2063, projekt VaV

Název: Fotometrický výzkum zákrytových dvojhvězd

Investor: Grantová agentura ČR, Fotometrický výzkum zákrytových dvojhvězd

Citovat

QIAN, Shengbang, Z.-B. DAI, J.-J. HE, J. Z. YUAN, F. Y. XIANG a Miloslav ZEJDA. Orbital period changes of the nova-like cataclysmic variable AC Cancri: evidence of magnetic braking and an unseen companion. Astronomy and Astrophysics. 2007, roč. 466, č. 2, s. 589-594. ISSN 0004-6361.

@article{772276,
   author = {Qian, Shengbang and Dai, Z.andB. and He, J.andJ. and Yuan, J. Z. and Xiang, F. Y. and Zejda, Miloslav},
   article_number = {2},
   keywords = {nova; cataclysmic variables; eclipsing binaries;AC Cnc; evolution; mass loss},
   language = {eng},
   issn = {0004-6361},
   journal = {Astronomy and Astrophysics},
   title = {Orbital period changes of the nova-like cataclysmic variable AC Cancri: evidence of magnetic braking and an unseen companion},
   url = {http://adsabs.harvard.edu/abs/2007A%26A...466..589Q},
   volume = {466},
   year = {2007}
}

TY  - JOUR
ID  - 772276
AU  - Qian, Shengbang - Dai, Z.-B. - He, J.-J. - Yuan, J. Z. - Xiang, F. Y. - Zejda, Miloslav
PY  - 2007
TI  - Orbital period changes of the nova-like cataclysmic variable AC Cancri: evidence of magnetic braking and an unseen companion
JF  - Astronomy and Astrophysics
VL  - 466
IS  - 2
SP  - 589-594
EP  - 589-594
SN  - 00046361
KW  - nova
KW  - cataclysmic variables
KW  - eclipsing binaries;AC Cnc
KW  - evolution
KW  - mass loss
UR  - http://adsabs.harvard.edu/abs/2007A%26A...466..589Q
N2  - Aims.The source AC Cnc is a nova-like cataclysmic variable containing a white-dwarf primary with a mass of 0.76 Mo and a K2-type secondary with a mass of 0.77 Mo. We intend to study its period changes and search for evidence of magnetic braking and unseen third body. Methods: The period changes were investigated based on the analysis of the O-C curve, which is formed by one new eclipse time together with the others compiled from the literature. Results: A cyclic change with a period of 16.2 yr was found to be superimposed on a long-term period decrease at a rate of dot{P}=-1.24(0.44).{10-8} days/year. Conclusions: It is shown that the mechanism of magnetic activity-driven changes in the quadrupole momentum of the secondary star (Applegate's mechanism) does not explain it easily. This period oscillation was plausibly interpreted by a light-travel time effect caused by the presence of a cool M-type dwarf companion (M_3<0.097 Mo) in a long orbit (16.2 yr) around the binary. Since the masses of both components are nearly the same, the mass transfer from the lobe-filling secondary to the primary is not efficient to cause the continuous period decrease. It may be strong evidence of an enhanced magnetic stellar wind from the K2-type component. If the Alfén radius of the cool secondary is the same as that of the Sun (i.e., RA = 15 Ro), the mass-loss rate should be dot{M_2}=-1.65.{10-10} Mo/year. By using the enhanced mass loss proposed by Tout and Eggleton (1988), the mass-loss rate should be dot{M_2}=-1.18.{10-9} Mo/year. In this case, the Alfén radius is determined to be RA = 5.2 Ro. However, the long-term decrease of the period may be only a part of a long-period (<100 yr) oscillation caused by the presence of an additional body. To check the conclusions, new precise times of light minimum will be required.
ER  -

QIAN, Shengbang, Z.-B. DAI, J.-J. HE, J. Z. YUAN, F. Y. XIANG a Miloslav ZEJDA. Orbital period changes of the nova-like cataclysmic variable AC Cancri: evidence of magnetic braking and an unseen companion. \textit{Astronomy and Astrophysics}. 2007, roč.~466, č.~2, s.~589-594. ISSN~0004-6361.

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