SW Lyncis

SW Lyncis

A visual band light curve for SW Lyncis, adapted from Ogloza et al. (1998)[1]
Observation data
Epoch J2000      Equinox J2000
Constellation Lynx
Right ascension 08h 07m 41.569s[2]
Declination +41° 48′ 01.74″[2]
Apparent magnitude (V) 9.58[3]
primary eclipse: 10.20
secondary eclipse: 9.65[4]
Characteristics
Spectral type F2 V[5]
B−V color index 0.255±0.041[3]
Variable type Detached Algol[4]
Astrometry
Radial velocity (Rv)+32.39±1.35[5] km/s
Proper motion (μ) RA: −16.887 mas/yr[2]
Dec.: −36.795 mas/yr[2]
Parallax (π)3.3655 ± 0.0571 mas[2]
Distance970 ± 20 ly
(297 ± 5 pc)
Orbit[5]
Period (P)0.644066 d
Eccentricity (e)0.00
Periastron epoch (T)2,451,400.1795±0.0025 HJD
Semi-amplitude (K1)
(primary)		116.73±1.65 km/s
Semi-amplitude (K2)
(secondary)		222.75±3.20 km/s
Details[6]
Primary
Mass1.77±0.37 M☉
Radius1.76±0.16 R☉
Luminosity10.15±0.15 L☉
Temperature7,800 K
Secondary
Mass0.92±0.18 M☉
Radius1.32±0.12 R☉
Luminosity0.64±0.01 L☉
Temperature4,588±6 K
Other designations
SW Lyn, BD+42°1811, HD 67008, HIP 39771, SAO 42180[7]
Database references
SIMBADdata

SW Lyncis is a binary or possibly a multiple-star system in the northern constellation of Lynx, abbreviated SW Lyn. With a combined apparent visual magnitude of 9.58,[3] it is too faint to be visible to the naked eye. The system is located at a distance of approximately 970 light years based on parallax measurements, and is drifting further away with a net radial velocity of about +32 km/s.[5]

The variable luminosity of this system was reported by R. Kippenhahn in 1955.[8] Huth in 1958 classified it as a β Lyr-type variable.[9] W. Strohmeier found a short period of 15.46 hours in 1959, although there was no minimum detected from a secondary eclipse. H. Mauder classified this as an eclipsing binary of the Algol type based on a light curve assembled in 1960. J. K. Gleim in 1967 noted that the period of the system had changed, suggesting that there may be a third body in the system. He considered it to be a member of the β Lyr class, although it is more closely related to the Algol type than W Ursae Majoris variables.[10]

M. Vetešník noted in 1968 that the light curve for the system appeared noticeably asymmetric.[9] He published orbital elements for this system in 1977 and found a stellar classification of F2V for the primary component. A low mass ratio suggested the secondary is much smaller and less luminous than the primary.[11] L. Qingyao and associates in 1991 concluded that this is a semi-detached system with one of the components filling its Roche lobe, and thought the secondary to be over-sized and over-luminous for its mass.[12] W. Ogłoza and associates in 1998 supported the idea of a semi-detached system, and found that the light curve suggested the presence of a third component in the system with an orbital period of 5.83 years.[1] The third component is thought to contribute less than 1.5% of the light output of the system.[13]

In 2010, C.-H. Kim and associates performed modelling of the 34-year cycle variations of the system and conjectured that two additional circumbinary companions are creating this effect. However, subsequent studies suggest that such a configuration would be too unstable. The system behavior remains unexplained.[14] SW Lyn is presently classified as a near contact binary that decreases in brightness to magnitude 10.20 during the primary eclipse and to magnitude 9.65 with the secondary eclipse.[15]

  1. ^ a b Cite error: The named reference Ogloza_et_al_1998 was invoked but never defined (see the help page).
  2. ^ a b c d Cite error: The named reference GaiaEDR3 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference Anderson_Francis_2012 was invoked but never defined (see the help page).
  4. ^ a b Cite error: The named reference Samus_et_al_2017 was invoked but never defined (see the help page).
  5. ^ a b c d Cite error: The named reference Lu_et_al_2001 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference kim2010 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Kippenhahn_1955 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Vetešnik_1968 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Gleim_1967 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Vetesnik_1977 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Qingyao_et_al_1991 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Kreiner_et_al_2003 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Hinse_et_al_2014 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Avvakumova_et_al_2013 was invoked but never defined (see the help page).