SZ Tauri

SZ Tauri

A light curve for SZ Tauri, plotted from TESS data[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Taurus
Right ascension 04h 37m 14.778s[2]
Declination +18° 32′ 34.93″[2]
Apparent magnitude (V) 6.39 to 6.69[3]
Characteristics
Evolutionary stage Supergiant
Spectral type F5Ib-F9.5Ib[4]
B−V color index 0.810±0.025[5]
Variable type δ Cep[6]
Astrometry
Radial velocity (Rv)−1.2±0.2[7] km/s
Proper motion (μ) RA: −4.403 mas/yr[2]
Dec.: −5.232 mas/yr[2]
Parallax (π)1.5741 ± 0.028 mas[2]
Distance2,070 ± 40 ly
(640 ± 10 pc)
Details
Mass6.1±0.8[8] M☉
Radius42.2±3.0[9] R☉
Luminosity1,905[10] L☉
Surface gravity (log g)2.0–2.2[11] cgs
Temperature6,015–6,420[10] K
Metallicity [Fe/H]0.08[11] dex
Age69–80[12] Myr
Other designations
SZ Tau, BD+18 661, GC 5621, HD 29260, HIP 21517, SAO 94036, PPM 120081[13]
Database references
SIMBADdata

SZ Tauri is a variable star in the equatorial constellation of Taurus. The brightness of this star varies from an apparent visual magnitude of 6.39 down to 6.69 with a period of 3.149 days,[3] which is near the lower limit of visibility to the naked eye. The distance to this star is approximately 2,070 light years based on parallax measurements.[2] There is some indication this may be a binary system, but the evidence is inconclusive.[14]

The variability of this star was announced by K. Schwarzschild in 1911 and was given a preliminary designation of 41.1910 with a period of 3.1484 d.[15][16] H. S. Leavitt extended the study up to 1914, producing a light curve with a period of 3.1487 d.[17] A 1916 spectral study by H. Shapley showed that the class of this pulsating Cepheid variable changed along the light curve, ranging from F7 at minimum up to A9 at peak luminosity.[18] Y. N. Efremov suggested in 1964 that this star may be a halo member of the NGC 1647 open cluster,[19] located 2.2° to the northeast. However, this was later disputed based on a poor proper motion match.[20] It was confirmed to be a classical Cepheid by W. P. Gieren in 1985.[21]

In the General Catalogue of Variable Stars, SZ Tau is classified as a Delta Cepheid of type DCEPS, which shows a nearly symmetric light curve with a small amplitude.[6] It is pulsating in the first overtone[19] and in evolutionary terms is undergoing its second crossing of the Cepheid instability strip.[12] By 1987, four changes in the pulsation period of SZ Tau had been observed;[22] the pulsation rate is decreasing by −0.49 s/yr.[12] The star is about 75[12] million years old with six[8] times the mass of the Sun and 42[9] times the Sun's radius. The effective temperature, radius, and spectral type of the star vary across each pulsation cycle.[10]

  1. ^ Cite error: The named reference MAST was invoked but never defined (see the help page).
  2. ^ a b c d e Cite error: The named reference GaiaEDR3 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference Klagyivik_Szabados_2009 was invoked but never defined (see the help page).
  4. ^ Cite error: The named reference Kraft1960 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Anderson_Francis_2012 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference Samus_et_al_2017 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference Gontcharov2006 was invoked but never defined (see the help page).
  8. ^ a b Cite error: The named reference Marconi_et_al_2020 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference Postma_Milone_2006 was invoked but never defined (see the help page).
  10. ^ a b c Cite error: The named reference Sanwal_et_al_1989 was invoked but never defined (see the help page).
  11. ^ a b Cite error: The named reference Andrievsky_et_al_2013 was invoked but never defined (see the help page).
  12. ^ a b c d Cite error: The named reference Fadeyev2015 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference Kervella_et_al_2019 was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Schwarzschild1911 was invoked but never defined (see the help page).
  16. ^ Cite error: The named reference Shapley1913 was invoked but never defined (see the help page).
  17. ^ Cite error: The named reference Leavitt_Pickering_1914 was invoked but never defined (see the help page).
  18. ^ Cite error: The named reference Shapley1916 was invoked but never defined (see the help page).
  19. ^ a b Cite error: The named reference Turner1992 was invoked but never defined (see the help page).
  20. ^ Cite error: The named reference Baumgardt_et_al_2000 was invoked but never defined (see the help page).
  21. ^ Cite error: The named reference Gieren1985 was invoked but never defined (see the help page).
  22. ^ Cite error: The named reference Trammell1987 was invoked but never defined (see the help page).