Psi Persei

Psi Persei (Psi Per, ψ Persei, ψ Per) is a single[7] Be star in the northern constellation of Perseus. It has an apparent visual magnitude of about 4.2, so it is visible to the naked eye at night under suitably dark skies. Based on parallax measurements, it is located at a distance of roughly 580 light-years (180 parsecs) from the Earth.

ψ Persei
Location of ψ Persei (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Perseus
Right ascension 03h 36m 29.37982s[1]
Declination +48° 11′ 33.4789″[1]
Apparent magnitude (V) 4.17 - 4.28[2]
Characteristics
Spectral type B5Ve[3]
U−B color index −0.56[4]
B−V color index −0.06[4]
Variable type γ Cas[5]
Astrometry
Radial velocity (Rv)−1.1[6] km/s
Proper motion (μ) RA: +22.55[1] mas/yr
Dec.: −27.78[1] mas/yr
Parallax (π)5.59 ± 0.22 mas[1]
Distance580 ± 20 ly
(179 ± 7 pc)
Absolute magnitude (MV)−2.03[7]
Details
Mass4.8[8] M☉
Radius5.5/7.26[9] R☉
Luminosity2,042[10] L☉
Surface gravity (log g)3.65[11] cgs
Temperature15,654[10] K
Rotational velocity (v sin i)275[11] km/s
Age63.1[12] Myr
Other designations
ψ Persei, ψ Per, Psi Per, 37 Persei, BD+47°857, GC 4287, HD 22192, HIP 16826, HR 1087, PPM 46127, SAO 46366[13]
Database references
SIMBADdata

Properties
A light curve for Psi Persei, plotted from TESS data,[14] with the period derived by Percy et al.[5] shown in red.

This star has a stellar classification of B5Ve,[3] which indicates it is a B-type main sequence star that is generating energy at its core through the nuclear fusion of hydrogen. It is a shell star with a circumstellar disc of gas surrounding the equator and extending out to about 11 times the radius of the star.[15] As a result of this disc, the spectrum of this star shows emission lines (as indicated by the 'e' in the stellar class) and its magnitude varies over a period 1.021 days.[5] The General Catalog of Variable Stars classifies Psi Persei as a gamma Cassiopeiae variable star, whose visual band brightness varies from magnitude 4.17 to 4.28.[16]

Psi Persei is rotating rapidly with a projected rotational velocity (v sin i) along the equator of 390 km/s or more.[17] The axis of rotation is inclined about 75° ± 8° to the line of sight from the Earth, so this velocity is close to the actual azimuthal velocity along the star's equator. It is expelling mass at the rate of about 5.0 × 10−8 times the mass of the Sun per year, or the equivalent of the Sun's mass every 20 million years.[15] The rapid rotation causes Psi Persei to be an oblate shape, with the equatorial radius being 7.3 R☉ and the polar radius to be 5.5 R☉.[9]

This star may be a member of the Alpha Persei Cluster, although its proper motion is high compared to other members.[18] Membership probabilities of 26% and 50% have been published from GALAH plus APOGEE data and from Gaia Data Release 2 data respectively.[19][20]

Name and etymology

This star, together with δ Per, σ Per, α Per, γ Per and η Per, has been called the Segment of Perseus.[21]

In Chinese, 天船 (Tiān Chuán), meaning Celestial Boat, refers to an asterism consisting of ψ Persei, η Persei, α Persei, γ Persei, δ Persei, 48 Persei, μ Persei and HD 27084. Consequently, the Chinese name for ψ Persei itself is 天船四 (Tiān Chuán sì, English: the Fourth Star of Celestial Boat.)[22]

References
  1. van Leeuwen, F. (November 2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.
  2. Samus, N. N.; et al. (2017). "General Catalogue of Variable Stars". Astronomy Reports. GCVS 5.1. 61 (1): 80–88. Bibcode:2017ARep...61...80S. doi:10.1134/S1063772917010085. S2CID 125853869.
  3. Lesh, Janet Rountree (December 1968). "The Kinematics of the Gould Belt: an Expanding Group?". Astrophysical Journal Supplement. 17: 371. Bibcode:1968ApJS...17..371L. doi:10.1086/190179.
  4. Johnson, H. L.; et al. (1966). "UBVRIJKL photometry of the bright stars". Communications of the Lunar and Planetary Laboratory. 4 (99): 99. Bibcode:1966CoLPL...4...99J.
  5. Percy, John R.; Ivans, Inese I.; Fried, Robert E.; Paparo, Margit (February 1994). "Short-term photometric variability of Psi Persei and Zeta Tauri". Publications of the Astronomical Society of the Pacific. 106 (696): 131–133. Bibcode:1994PASP..106..131P. doi:10.1086/133356.
  6. Evans, D. S. (June 20–24, 1966). "The Revision of the General Catalogue of Radial Velocities". In Batten, Alan Henry; Heard, John Frederick (eds.). Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30. University of Toronto: International Astronomical Union (published 1967). pp. 57–63. Bibcode:1967IAUS...30...57E.
  7. Hutter, D. J.; Tycner, C.; Zavala, R. T.; Benson, J. A.; Hummel, C. A.; Zirm, H. (2021). "Surveying the Bright Stars by Optical Interferometry. III. A Magnitude-limited Multiplicity Survey of Classical be Stars". The Astrophysical Journal Supplement Series. 257 (2): 69. arXiv:2109.06839. Bibcode:2021ApJS..257...69H. doi:10.3847/1538-4365/ac23cb. S2CID 237503492.
  8. Sheikhi, Najmeh; et al. (March 2016). "The binary fraction and mass segregation in Alpha Persei open cluster". Monthly Notices of the Royal Astronomical Society. 457 (1): 1028–1036. arXiv:1601.02186. Bibcode:2016MNRAS.457.1028S. doi:10.1093/mnras/stw059.
  9. Klement, R.; Carciofi, A. C.; Rivinius, T.; Matthews, L. D.; Vieira, R. G.; Ignace, R.; Bjorkman, J. E.; Mota, B. C.; Faes, D. M.; Bratcher, A. D.; Curé, M.; Štefl, S. (2017). "Revealing the structure of the outer disks of be stars". Astronomy and Astrophysics. 601: A74. arXiv:1703.07321. Bibcode:2017A&A...601A..74K. doi:10.1051/0004-6361/201629932. S2CID 56439879.
  10. Silaj, J.; Landstreet, J. D. (2014). "Accurate age determinations of several nearby open clusters containing magnetic Ap stars". Astronomy & Astrophysics. 566: A132. arXiv:1407.4531. Bibcode:2014A&A...566A.132S. doi:10.1051/0004-6361/201321468. S2CID 53370832.
  11. Zorec, J.; et al. (November 2016). "Critical study of the distribution of rotational velocities of Be stars. I. Deconvolution methods, effects due to gravity darkening, macroturbulence, and binarity". Astronomy & Astrophysics. 595: 26. Bibcode:2016A&A...595A.132Z. doi:10.1051/0004-6361/201628760.
  12. Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011). "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun". Monthly Notices of the Royal Astronomical Society. 410 (1): 190–200. arXiv:1007.4883. Bibcode:2011MNRAS.410..190T. doi:10.1111/j.1365-2966.2010.17434.x. S2CID 118629873.
  13. "psi Per -- Be Star". SIMBAD. Centre de Données astronomiques de Strasbourg. Retrieved 2011-02-24.
  14. "MAST: Barbara A. Mikulski Archive for Space Telescopes". Space Telescope Science Institute. Retrieved 20 December 2022.
  15. Delaa, O.; et al. (May 2011). "Kinematics and geometrical study of the Be stars 48 Persei and ψ Persei with the VEGA/CHARA interferometer". Astronomy & Astrophysics. 529: A87. Bibcode:2011A&A...529A..87D. doi:10.1051/0004-6361/201015639.
  16. "psi Per". General Catalog of Variable Stars. Sternberg Astronomical Institute. Retrieved 20 December 2022.
  17. Bernacca, P. L.; Perinotto, M. (1970). "A Catalogue of Stellar Rotational Velocities". Contributi Osservatorio Astronomico di Padova in Asiago. 239 (1): 1. Bibcode:1970CoAsi.239....1B.
  18. Morrell, Nidia; Abt, Helmut A. (July 10, 1992). "Spectroscopic binaries in the Alpha Persei cluster". Astrophysical Journal, Part 1. 393 (2): 666–673. Bibcode:1992ApJ...393..666M. doi:10.1086/171534.
  19. Spina, L.; et al. (2021). "The GALAH survey: Tracing the Galactic disc with open clusters". Monthly Notices of the Royal Astronomical Society. 503 (3): 3279. arXiv:2011.02533. Bibcode:2021MNRAS.503.3279S. doi:10.1093/mnras/stab471.
  20. Cantat-Gaudin, T.; Jordi, C.; Vallenari, A.; Bragaglia, A.; Balaguer-Núñez, L.; Soubiran, C.; Bossini, D.; Moitinho, A.; Castro-Ginard, A.; Krone-Martins, A.; Casamiquela, L.; Sordo, R.; Carrera, R. (2018). "A Gaia DR2 view of the open cluster population in the Milky Way". Astronomy and Astrophysics. 618: A93. arXiv:1805.08726. Bibcode:2018A&A...618A..93C. doi:10.1051/0004-6361/201833476. S2CID 56245426.
  21. Allen, R. H. (1963). Star Names: Their Lore and Meaning (Reprint ed.). New York: Dover Publications Inc. p. 331. ISBN 0-486-21079-0. Retrieved 2012-09-04.
  22. (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日
  23. 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.
  24. Underhill, A. B.; et al. (November 1979). "Effective temperatures, angular diameters, distances and linear radii for 160 O and B stars". Monthly Notices of the Royal Astronomical Society. 189 (3): 601–605. Bibcode:1979MNRAS.189..601U. doi:10.1093/mnras/189.3.601.
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