TZ Mensae

A light curve for TZ Mensae plotted from TESS data[1]
Observation data
Epoch J2000.0      Equinox J2000.0 (ICRS)
Constellation Mensa
Right ascension 05h 30m 13.8827s[2]
Declination −84° 47′ 06.366″[2]
Apparent magnitude (V) 6.19 to 6.87[3]
Characteristics
U−B color index −0.11[4]
B−V color index −0.02[4]
Variable type Algol variable[5]
A
Spectral type A0 V[6]
B
Spectral type A8 V[6]
Astrometry
Radial velocity (Rv)−0.3±0.9[7] km/s
Proper motion (μ) RA: −6.242 mas/yr[2]
Dec.: +43.141 mas/yr[2]
Parallax (π)8.0907 ± 0.0381 mas[2]
Distance403 ± 2 ly
(123.6 ± 0.6 pc)
Absolute magnitude (MV)+0.93[8] (combined)
Orbit[9]
PrimaryA
CompanionB
Period (P)8.569 d
Semi-major axis (a)0.13 AU
Eccentricity (e)0.035±0.007
Inclination (i)88.73°
Periastron epoch (T)2442403.7085
Argument of periastron (ω)
(secondary)		295°
Semi-amplitude (K1)
(primary)		62.2 km/s
Semi-amplitude (K2)
(secondary)		102.8 km/s
Details[10]
A
Mass2.49±0.02 M☉
Radius1.90±0.02 R☉
Luminosity39.8+7
−6 L☉
Surface gravity (log g)4.22±0.01[9] cgs
Temperature10,543+421
−405 K
Rotational velocity (v sin i)16±4[9] km/s
B
Mass1.50±0.01 M☉
Radius1.40±0.01 R☉
Luminosity4.57+0.8
−0.7 L☉
Surface gravity (log g)4.30±0.01[9] cgs
Temperature7178+303
−291 K
Rotational velocity (v sin i)12[9] km/s
Metallicity [Fe/H]−0.12±0.05[6] dex
Age141±3[6] Myr
Other designations
31 G. Mensae[11], TZ Men, CD−84°63, CPD−84°75, FK5 1659, GC 7134, HD 39780, HIP 25776, HR 2059, SAO 258418[12]
Database references
SIMBADdata

TZ Mensae is a binary star in the southern circumpolar constellation Mensa. The system has a combined maximum apparent magnitude of 6.19,[13] placing it near the limit for naked eye visibility. Parallax measurements place the system at a distance of 403 light years.[2] The radial velocity is small.[7]

The components of TZ Mensae have stellar classifications of A0 V and A8 V,[6] both indicating that they are ordinary A-type main-sequence stars. They have masses of 1.5 and 2.5 M☉, and radii of 1.4 and 1.9 R☉, respectively.[10] The primary has an effective temperature of 10,543 K and a luminosity 40 times that of the Sun (L☉).[10] As for the companion, it has a temperature of 7,178 K. and a luminosity less than five L☉[10] The rotation of both stars is apparently synchronous with the orbital period, with projected rotational velocities of 12 and 16 km/s respectively.[9] The system is estimated to be 141 million years old.[6]

The two components take about 8 days to revolve around each other in a relatively circular orbit.[9] Since the inclination is close to 90° (actually 88.7°),[9] the two stars periodically pass in front of one another and it has been classified as a eclipsing binary, specifically the Algol type.[5] If the brighter component is eclipsing the dimmer one, the brightness drops to 6.36.[5] If vice versa, it drops to 6.87,[3] which is below the limit for naked eye visibility.

References

  1. ^ "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 8 December 2021.
  2. ^ a b c d e Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  3. ^ a b Watson, C. L.; Henden, A. A.; Price, A. (May 2006). "The International Variable Star Index (VSX)". Society for Astronomical Sciences Annual Symposium. 25: 47. Bibcode:2006SASS...25...47W.
  4. ^ a b Johnson, H. L.; Mitchell, R. I.; Iriarte, B.; Wisniewski, W. Z. (1966). "UBVRIJKL Photometry of the Bright Stars". Communications of the Lunar and Planetary Laboratory. 4: 99–110. Bibcode:1966CoLPL...4...99J.
  5. ^ a b c Samus’, N. N.; Kazarovets, E. V.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (January 2017). "General catalogue of variable stars: Version GCVS 5.1". Astronomy Reports. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. ISSN 1063-7729. S2CID 255195566.
  6. ^ a b c d e f Kovaleva, D. A. (December 2001). "Age and metallicity estimates for moderate-mass stars in eclipsing binaries". Astronomy Reports. 45 (12): 972–983. Bibcode:2001ARep...45..972K. doi:10.1134/1.1426128. eISSN 1562-6881. ISSN 1063-7729. S2CID 121028634.
  7. ^ a b Gontcharov, G. A. (November 2006). "Pulkovo Compilation of Radial Velocities for 35 495 Hipparcos stars in a common system". Astronomy Letters. 32 (11): 759–771. arXiv:1606.08053. Bibcode:2006AstL...32..759G. doi:10.1134/S1063773706110065. ISSN 1063-7737. S2CID 119231169.
  8. ^ Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters. 38 (5): 331. arXiv:1108.4971. Bibcode:2012AstL...38..331A. doi:10.1134/S1063773712050015. S2CID 119257644.
  9. ^ a b c d e f g h Andersen, J.; Clausen, J. V.; Nordstrom, B. (March 1987). "Absolute dimensions of eclipsing binaries. XII. TZ Mensae". Astronomy and Astrophysics. 175: 60–70. Bibcode:1987A&A...175...60A. ISSN 0004-6361.
  10. ^ a b c d Malkov, O. Yu. (January 1993). "Catalogue of astrophysical parameters of binary systems". Bulletin d'Information du Centre de Donnees Stellaires. 42: 27. Bibcode:1993BICDS..42...27M. ISSN 1169-8837.
  11. ^ Gould, Benjamin Apthorp (1878). "Uranometria Argentina : brillantez y posicion de las estrellas fijas, hasta la septima magnitud, comprendidas dentro de cien grados del polo austral : con atlas". Resultados del Observatorio Nacional Argentino. 1. Bibcode:1879RNAO....1.....G.
  12. ^ "TZ Men". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved July 9, 2022.
  13. ^ Høg, E.; Fabricius, C.; Makarov, V. V.; Urban, S.; Corbin, T.; Wycoff, G.; Bastian, U.; Schwekendiek, P.; Wicenec, A. (March 2000). "The Tycho-2 catalogue of the 2.5 million brightest stars". Astronomy and Astrophysics. 355: L27–L30. Bibcode:2000A&A...355L..27H. ISSN 0004-6361.
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