AE Phoenicis

Star in the constellation Phoenix

AE Phoenicis
Observation data Epoch J2000 Equinox J2000
A light curve for AE Phoenicis, plotted from TESS data^[1]
Constellation	Phoenix
Right ascension	01^h 32^m 32.93^s^[2]
Declination	−49° 31′ 41.29″^[2]
Apparent magnitude (V)	7.56 – 8.25^[3]
Characteristics
Evolutionary stage	G0V + G0V^[3]
Variable type	W UMa^[3]
Astrometry

Radial velocity (R_v)	21.2^[4] km/s
Proper motion (μ)	RA: +151.48^[2] mas/yr Dec.: -53.94^[2] mas/yr
Parallax (π)	19.4490 ± 0.0260 mas^[2]
Distance	167.7 ± 0.2 ly (51.42 ± 0.07 pc)
Absolute magnitude (M_V)	4.104^[5]

Details

Age	3.20 ± 1.62^[6] Gyr


Primary
Mass	1.38 ± 0.06^[7] `M`_☉
Radius	1.29 ± 0.03^[7] `R`_☉
Luminosity	1.74^+0.30 _−0.26^[7] `L`_☉
Temperature	6,083^[8] K
Secondary
Mass	0.63 ± 0.02^[7] `M`_☉
Radius	0.81 ± 0.02^[7] `R`_☉
Luminosity	0.83^+0.15 _−0.12^[7] `L`_☉
Temperature	6,310^[8] K
Other designations
AE Phe, CD−50°410, HD 9528, HIP 7183, SAO 215545^[9]
Database references
SIMBAD	data

AE Phoenicis is a variable star in the constellation of Phoenix. An eclipsing binary, its apparent magnitude has a maximum of 7.56, dimming to 8.25 during primary eclipse and 8.19 during secondary eclipse.^[3] From parallax measurements by the Gaia spacecraft, the system is located at a distance of 168 light-years (51.4 parsecs) from Earth.^[2]

AE Phoenicis is a contact binary of W Ursae Majoris type, composed of two stars so close that their surfaces touch each other. They are separated by 2.70 solar radii^[6] and orbit each other with a period of 0.3624 days.^[8] They are both classified as G-type main-sequence stars of spectral type G0V.^[3] With effective temperatures of 6,083 and 6,310 K, the system is classified as a W Ursae Majoris variable of subtype W, where the secondary star is hotter than the primary; for this reason, the primary eclipses are caused by the occultation of the secondary star.^[8] The orbit is circular^[10] and is inclined by 86.5° in relation to the plane of the sky.^[8]

The combination of photometric and spectroscopic data have allowed the direct determination of the parameters of the stars. The primary component has a mass of 1.38 times the solar mass and a radius of 1.29 times the solar radius, while the secondary has 0.63 times the solar mass and 0.81 times the solar radius.^[7] In visible light, the primary star contributes 66.5% of the system's luminosity, while the secondary contributes the rest (33.5%).^[8] The light curve shows asymmetries and variations that indicate starspots on the surface of the stars. The reconstruction of the surface of the system by Doppler imaging revealed significant spot coverage in the entire surface of both stars, and the spots seem to evolve in a timescale of days.^[4]

Since the stars are in contact, there is considerable mass transfer from the secondary to the primary. It is estimated that the secondary star was initially the more massive star, with 1.69 times the solar mass, while the primary had an initial mass of 1.02 times the solar mass.^[6] Observations show the orbital period of the system to be increasing at a rate of 6.17×10⁻⁸ days per year, which is direct evidence of this mass transfer.^[8] The system was born as a detached binary with an estimated separation of 12.39 solar radii and period of 3.07 days, which by angular momentum loss evolved to the current contact configuration.^[6] In the future the two stars will probably merge into a single, fast-rotating star.^[11]

Gaia Data Release 2 catalogued a 16.0-magnitude star (G band) with very similar parallax and proper motions to AE Phoenicis. It is separated from AE Phoenicis by 6.0 arcseconds and has a temperature of 4,640 K.^[12]

References

^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
^ ^a ^b ^c ^d ^e ^f Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
^ ^a ^b ^c ^d ^e Samus', N. N; Kazarovets, E. V; Durlevich, O. V; Kireeva, N. N; Pastukhova, E. N (2017), "General catalogue of variable stars: Version GCVS 5.1", Astronomy Reports, 61 (1): 80, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
^ ^a ^b Barnes, J. R.; Lister, T. A.; Hilditch, R. W.; Collier Cameron, A. (2004). "High-resolution Doppler images of the spotted contact binary AE Phe". Monthly Notices of the Royal Astronomical Society. 348 (4): 1321. Bibcode:2004MNRAS.348.1321B. doi:10.1111/j.1365-2966.2004.07452.x.
^ Eker, Z.; Bilir, S.; Yaz, E.; Demircan, O.; Helvaci, M. (2009). "New absolute magnitude calibrations for W Ursa Majoris type binaries". Astronomische Nachrichten. 330 (1): 68. arXiv:0807.4989. Bibcode:2009AN....330...68E. doi:10.1002/asna.200811041. S2CID 15071352.
^ ^a ^b ^c ^d Yıldız, M. (2014). "Origin of W UMa-type contact binaries - age and orbital evolution". Monthly Notices of the Royal Astronomical Society. 437 (1): 185–194. arXiv:1310.5526. Bibcode:2014MNRAS.437..185Y. doi:10.1093/mnras/stt1874. S2CID 119121897.
^ ^a ^b ^c ^d ^e ^f ^g Hilditch, R. W.; King, D. J.; McFarlane, T. M. (1988). "The evolutionary state of contact and near-contact binary stars". Monthly Notices of the Royal Astronomical Society. 231 (2): 341–352. Bibcode:1988MNRAS.231..341H. doi:10.1093/mnras/231.2.341.
^ ^a ^b ^c ^d ^e ^f ^g He, J. -J; Qian, S. -B.; Fernández Lajús, E.; Fariña, C. (2009). "A Charge-Coupled Device Photometric Study of South Hemispheric Contact Binary AE Phoenicis". The Astronomical Journal. 138 (5): 1465. Bibcode:2009AJ....138.1465H. doi:10.1088/0004-6256/138/5/1465. hdl:11336/42802.
^ "AE Phe". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 27 January 2019.
^ Duerbeck, H. W. (1978). "The orbit of AE Phe - revisited". Acta Astronomica. 28: 49. Bibcode:1978AcA....28...49D.
^ Gazeas, K.; Stȩpień, K. (2008). "Angular momentum and mass evolution of contact binaries". Monthly Notices of the Royal Astronomical Society. 390 (4): 1577. arXiv:0803.0212. Bibcode:2008MNRAS.390.1577G. doi:10.1111/j.1365-2966.2008.13844.x.
^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.

Constellation of Phoenix

Stars

Bayer	α (Ankaa) β γ δ ε ζ (Wurren) η θ ι κ λ¹ λ² μ ν ξ π ρ σ τ υ φ χ ψ ω
Variable	RV SX YZ AD AE AI AW AZ BB BD
HR	6 23 73 109 111 120 140 148 162 171 198 202 209 229 299 350 408 411 443 447 519 524 537 574 588 632 636 659 686 698 706 8910 8920 8929 8959 8993 9001 9046 9077 9082
HD	2039 5388 6434 (Nenque) 8535 9895 11421 13218 13387 223549 224782
Other	CD-44 170 BPM 30551 HE 0107-5240 NGC 405 WASP-4 WASP-5 WASP-18 WASP-29 WASP-96 WD 2359-434