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Epsilon Cassiopeiae

February 15, 2024

Epsilon Cassiopeiae or ε Cassiopeiae, officially named Segin (/ˈsɛɡɪn/),[10][11] is a single[12] star in the northern constellation of Cassiopeia. With an apparent visual magnitude of 3.4, this is one of the brightest stars in the constellation. The distance to this star has been determined directly using parallax measurements, yielding a value of around 460–430 light-years (140–130 parsecs) from the Sun. It is drifting closer with a radial velocity of −8 km/s.[5]

Epsilon Cassiopeiae
Location of ε Cas (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Cassiopeia
Right ascension 01h 54m 23.73409s[1]
Declination +63° 40′ 12.3602″[1]
Apparent magnitude (V) 3.37[2]
Characteristics
Spectral type B3 V[3]
U−B color index −0.62[2]
B−V color index −0.15[2]
Variable type Periodic[4]
Astrometry
Radial velocity (Rv)−8.1[5] km/s
Proper motion (μ) RA: +29.587[1] mas/yr
Dec.: −18.387[1] mas/yr
Parallax (π)7.0037 ± 0.1599 mas[1]
Distance470 ± 10 ly
(143 ± 3 pc)
Absolute magnitude (MV)−2.19[6]
Details
Mass9.2±0.2[7] M☉
Radius6.10±0.06[1] R☉
Luminosity3,059[1] L☉
Surface gravity (log g)3.5[8] cgs
Temperature15,174[8] K
Metallicity [Fe/H]−0.28[1] dex
Rotational velocity (v sin i)30[9] km/s
Age15.4±3.0[7] Myr
Other designations
Segin, Epsilon Cas, ε Cas, 45 Cassiopeiae, BD+62 320, FK5 63, HD 11415, HIP 8886, HR 542, SAO 12031
Database references
SIMBADdata

Nomenclature edit

ε Cassiopeiae, Latinised to Epsilon Cassiopeiae, is the star's Bayer catalog designation.

The star bore the traditional name Segin, which probably originates from an erroneous transcription of Seginus, the traditional name for Gamma Boötis, which itself is of uncertain origin.[13] Different sources report varying pronunciations, with SEG-in the most common but the variants SAY-gin and seg-EEN also appearing.[13][14] In 2016, the IAU organized a Working Group on Star Names (WGSN)[15] to catalog and standardize proper names for stars. The WGSN approved the name Segin for this star on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.[11]

While some published reports incorrectly claim that this star was designated by NASA as Navi ('Ivan', backwards), in honor of astronaut Virgil Ivan "Gus" Grissom, one of the three astronauts who died in the Apollo 1 accident,[16] the actual star so designated is Gamma Cassiopeiae in the center of the constellation.[17][18]

In Chinese, 閣道 (Gé Dào), meaning Flying Corridor, refers to an asterism consisting of Epsilon Cassiopeiae, Iota Cassiopeiae, Delta Cassiopeiae, Theta Cassiopeiae, Nu Cassiopeiae and Omicron Cassiopeiae.[19] Consequently, the Chinese name for Epsilon Cassiopeiae itself is 閣道二 (Gé Dào èr, English: the Second Star of Flying Corridor.)[20]

Properties edit

 
A light curve for Epsilon Cassiopeiae, plotted from Hipparcos data[21]

Epsilon Cassiopeiae has a stellar classification of B3 V, indicating that it is a main sequence star fusing hydrogen in its core. Cote et al. (2003) indicate that it displays the spectral properties of a Be star, even though it is not categorized as such.[22] The presence of emission lines in the spectrum indicates the presence of a circumstellar shell of gas that has been thrown off by the star.[23] Epsilon Cassiopeiae has nine[7] times the mass and six times the radius of the Sun. It is radiating 3,000 times the luminosity of the Sun from its photosphere at an effective temperature of 15,174 K (14,901 °C; 26,854 °F),[8] giving it the blue-white hue of a B-type star.[24]

Observation during the Hipparcos mission suggest that the star may undergo weak periodic variability. The amplitude of this variation is 0.0025 in magnitude with a frequency of 11.17797 times per day, or one cycle every 2.15 hours. The signal-to-noise ratio for this measured variation is 4.978.[4] Hipparcos measurements of the space velocity components for this star suggest that it is a member of the Cas-Tau group of co-moving stars, with a 93% likelihood. This group may be kinematically associated with the alpha Persei Cluster, indicating that the Cas-Tau group, including Epsilon Cassiopeiae, may have been separated from the cluster through tidal interactions.[25]

References edit

  1. ^ a b c d e f g h Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv:2208.00211. Bibcode:2023A&A...674A...1G. doi:10.1051/0004-6361/202243940. S2CID 244398875. Gaia DR3 record for this source at VizieR.
  2. ^ a b c 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
  3. ^ Slettebak, A. (1982). "Spectral types and rotational velocities of the brighter Be stars and A-F type shell stars". Astrophysical Journal Supplement Series. 50: 55. Bibcode:1982ApJS...50...55S. doi:10.1086/190820.
  4. ^ a b Koen, Chris; Eyer, Laurent (March 2002), "New periodic variables from the Hipparcos epoch photometry", Monthly Notices of the Royal Astronomical Society, 331 (1): 45–59, arXiv:astro-ph/0112194, Bibcode:2002MNRAS.331...45K, doi:10.1046/j.1365-8711.2002.05150.x, S2CID 10505995
  5. ^ a b Wielen, R.; et al. (1999), "Sixth Catalogue of Fundamental Stars (FK6). Part I. Basic fundamental stars with direct solutions", Veröff. Astron. Rechen-Inst. Heidelb, Astronomisches Rechen-Institut Heidelberg, 35 (35): 1, Bibcode:1999VeARI..35....1W
  6. ^ Huang, W.; et al. (2012), "A catalogue of Paschen-line profiles in standard stars", Astronomy & Astrophysics, 547: A62, arXiv:1210.7893, Bibcode:2012A&A...547A..62H, doi:10.1051/0004-6361/201219804, S2CID 119286159.
  7. ^ a b c 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
  8. ^ a b c Takeda, Yoichi; et al. (October 2010), "Oxygen and Neon Abundances of B-Type Stars in Comparison with the Sun", Publications of the Astronomical Society of Japan, 62 (5): 1239–1248, arXiv:1008.1220, Bibcode:2010PASJ...62.1239T, doi:10.1093/pasj/62.5.1239, S2CID 118536224
  9. ^ Abt, Helmut A.; Levato, Hugo; Grosso, Monica (July 2002), "Rotational Velocities of B Stars", The Astrophysical Journal, 573 (1): 359–365, Bibcode:2002ApJ...573..359A, doi:10.1086/340590
  10. ^ starrynighteducation.com, Audio Pronunciation Guide
  11. ^ a b "Naming Stars". IAU.org. Retrieved 16 December 2017.
  12. ^ 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.
  13. ^ a b Simpson, Phil (2012). "3". Guidebook to the constellations. New York: Springer. ISBN 9781441969408.
  14. ^ "Audio Pronunciation Guide". Starry Night Education. Retrieved 7 August 2014.
  15. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  16. ^ Rao, Joe (August 29, 2003). "NightSky Friday: Rotanev, Derf, Navi, and other Backward Star Names". Space.com.
  17. ^ "Post-landing Activities". Apollo 15 Lunar Surface Journal. NASA. commentary at 105:11:33
  18. ^ "Apollo 10 Flown CSM Star Chart Directly from the Personal Collection of Mission Command Module Pilot John Young". Heritage Auction Galleries. Retrieved March 11, 2010.
  19. ^ (in Chinese) 中國星座神話, written by 陳久金. Published by 台灣書房出版有限公司, 2005, ISBN 978-986-7332-25-7.
  20. ^ (in Chinese) 香港太空館 - 研究資源 - 亮星中英對照表 August 18, 2010, at the Wayback Machine, Hong Kong Space Museum. Accessed on line November 23, 2010.
  21. ^ "Light Curve", Hipparcos ESA, ESA, retrieved 10 October 2022.
  22. ^ Cote, J.; van Kerkwijk, M. H. (July 1993), "New Bright Be-Stars and the Be-Star Frequency", Astronomy and Astrophysics, 274 (3): 870, Bibcode:1993A&A...274..870C
  23. ^ Andrillat, A.; Jaschek, M.; Jaschek, C. (July 1990), "A survey of Be stars in the infrared. II - Determination of envelope dimensions", Astronomy and Astrophysics Supplement Series, 84 (1): 11–28, Bibcode:1990A&AS...84...11A
  24. ^ , Australia Telescope, Outreach and Education, Commonwealth Scientific and Industrial Research Organisation, December 21, 2004, archived from the original on 2012-03-18, retrieved 2012-01-16
  25. ^ de Zeeuw, P. T.; et al. (January 1999), "A HIPPARCOS Census of the Nearby OB Associations", The Astronomical Journal, 117 (1): 354–399, arXiv:astro-ph/9809227, Bibcode:1999AJ....117..354D, doi:10.1086/300682, S2CID 16098861

External links edit

February 15, 2024
epsilon, cassiopeiae, cassiopeiae, officially, named, segin, single, star, northern, constellation, cassiopeia, with, apparent, visual, magnitude, this, brightest, stars, constellation, distance, this, star, been, determined, directly, using, parallax, measure. Epsilon Cassiopeiae or e Cassiopeiae officially named Segin ˈ s ɛ ɡ ɪ n 10 11 is a single 12 star in the northern constellation of Cassiopeia With an apparent visual magnitude of 3 4 this is one of the brightest stars in the constellation The distance to this star has been determined directly using parallax measurements yielding a value of around 460 430 light years 140 130 parsecs from the Sun It is drifting closer with a radial velocity of 8 km s 5 Epsilon CassiopeiaeLocation of e Cas circled Observation dataEpoch J2000 Equinox J2000Constellation CassiopeiaRight ascension 01h 54m 23 73409s 1 Declination 63 40 12 3602 1 Apparent magnitude V 3 37 2 CharacteristicsSpectral type B3 V 3 U B color index 0 62 2 B V color index 0 15 2 Variable type Periodic 4 AstrometryRadial velocity Rv 8 1 5 km sProper motion m RA 29 587 1 mas yr Dec 18 387 1 mas yrParallax p 7 0037 0 1599 mas 1 Distance470 10 ly 143 3 pc Absolute magnitude MV 2 19 6 DetailsMass9 2 0 2 7 M Radius6 10 0 06 1 R Luminosity3 059 1 L Surface gravity log g 3 5 8 cgsTemperature15 174 8 KMetallicity Fe H 0 28 1 dexRotational velocity v sin i 30 9 km sAge15 4 3 0 7 MyrOther designationsSegin Epsilon Cas e Cas 45 Cassiopeiae BD 62 320 FK5 63 HD 11415 HIP 8886 HR 542 SAO 12031Database referencesSIMBADdata Contents 1 Nomenclature 2 Properties 3 References 4 External linksNomenclature edite Cassiopeiae Latinised to Epsilon Cassiopeiae is the star s Bayer catalog designation The star bore the traditional name Segin which probably originates from an erroneous transcription of Seginus the traditional name for Gamma Bootis which itself is of uncertain origin 13 Different sources report varying pronunciations with SEG in the most common but the variants SAY gin and seg EEN also appearing 13 14 In 2016 the IAU organized a Working Group on Star Names WGSN 15 to catalog and standardize proper names for stars The WGSN approved the name Segin for this star on 5 September 2017 and it is now so included in the List of IAU approved Star Names 11 While some published reports incorrectly claim that this star was designated by NASA as Navi Ivan backwards in honor of astronaut Virgil Ivan Gus Grissom one of the three astronauts who died in the Apollo 1 accident 16 the actual star so designated is Gamma Cassiopeiae in the center of the constellation 17 18 In Chinese 閣道 Ge Dao meaning Flying Corridor refers to an asterism consisting of Epsilon Cassiopeiae Iota Cassiopeiae Delta Cassiopeiae Theta Cassiopeiae Nu Cassiopeiae and Omicron Cassiopeiae 19 Consequently the Chinese name for Epsilon Cassiopeiae itself is 閣道二 Ge Dao er English the Second Star of Flying Corridor 20 Properties edit nbsp A light curve for Epsilon Cassiopeiae plotted from Hipparcos data 21 Epsilon Cassiopeiae has a stellar classification of B3 V indicating that it is a main sequence star fusing hydrogen in its core Cote et al 2003 indicate that it displays the spectral properties of a Be star even though it is not categorized as such 22 The presence of emission lines in the spectrum indicates the presence of a circumstellar shell of gas that has been thrown off by the star 23 Epsilon Cassiopeiae has nine 7 times the mass and six times the radius of the Sun It is radiating 3 000 times the luminosity of the Sun from its photosphere at an effective temperature of 15 174 K 14 901 C 26 854 F 8 giving it the blue white hue of a B type star 24 Observation during the Hipparcos mission suggest that the star may undergo weak periodic variability The amplitude of this variation is 0 0025 in magnitude with a frequency of 11 17797 times per day or one cycle every 2 15 hours The signal to noise ratio for this measured variation is 4 978 4 Hipparcos measurements of the space velocity components for this star suggest that it is a member of the Cas Tau group of co moving stars with a 93 likelihood This group may be kinematically associated with the alpha Persei Cluster indicating that the Cas Tau group including Epsilon Cassiopeiae may have been separated from the cluster through tidal interactions 25 References edit a b c d e f g h Vallenari A et al Gaia collaboration 2023 Gaia Data Release 3 Summary of the content and survey properties Astronomy and Astrophysics 674 A1 arXiv 2208 00211 Bibcode 2023A amp A 674A 1G doi 10 1051 0004 6361 202243940 S2CID 244398875 Gaia DR3 record for this source at VizieR a b c 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 Slettebak A 1982 Spectral types and rotational velocities of the brighter Be stars and A F type shell stars Astrophysical Journal Supplement Series 50 55 Bibcode 1982ApJS 50 55S doi 10 1086 190820 a b Koen Chris Eyer Laurent March 2002 New periodic variables from the Hipparcos epoch photometry Monthly Notices of the Royal Astronomical Society 331 1 45 59 arXiv astro ph 0112194 Bibcode 2002MNRAS 331 45K doi 10 1046 j 1365 8711 2002 05150 x S2CID 10505995 a b Wielen R et al 1999 Sixth Catalogue of Fundamental Stars FK6 Part I Basic fundamental stars with direct solutions Veroff Astron Rechen Inst Heidelb Astronomisches Rechen Institut Heidelberg 35 35 1 Bibcode 1999VeARI 35 1W Huang W et al 2012 A catalogue of Paschen line profiles in standard stars Astronomy amp Astrophysics 547 A62 arXiv 1210 7893 Bibcode 2012A amp A 547A 62H doi 10 1051 0004 6361 201219804 S2CID 119286159 a b c Tetzlaff N Neuhauser 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 a b c Takeda Yoichi et al October 2010 Oxygen and Neon Abundances of B Type Stars in Comparison with the Sun Publications of the Astronomical Society of Japan 62 5 1239 1248 arXiv 1008 1220 Bibcode 2010PASJ 62 1239T doi 10 1093 pasj 62 5 1239 S2CID 118536224 Abt Helmut A Levato Hugo Grosso Monica July 2002 Rotational Velocities of B Stars The Astrophysical Journal 573 1 359 365 Bibcode 2002ApJ 573 359A doi 10 1086 340590 starrynighteducation com Audio Pronunciation Guide a b Naming Stars IAU org Retrieved 16 December 2017 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 a b Simpson Phil 2012 3 Guidebook to the constellations New York Springer ISBN 9781441969408 Audio Pronunciation Guide Starry Night Education Retrieved 7 August 2014 IAU Working Group on Star Names WGSN Retrieved 22 May 2016 Rao Joe August 29 2003 NightSky Friday Rotanev Derf Navi and other Backward Star Names Space com Post landing Activities Apollo 15 Lunar Surface Journal NASA commentary at 105 11 33 Apollo 10 Flown CSM Star Chart Directly from the Personal Collection of Mission Command Module Pilot John Young Heritage Auction Galleries Retrieved March 11 2010 in Chinese 中國星座神話 written by 陳久金 Published by 台灣書房出版有限公司 2005 ISBN 978 986 7332 25 7 in Chinese 香港太空館 研究資源 亮星中英對照表 Archived August 18 2010 at the Wayback Machine Hong Kong Space Museum Accessed on line November 23 2010 Light Curve Hipparcos ESA ESA retrieved 10 October 2022 Cote J van Kerkwijk M H July 1993 New Bright Be Stars and the Be Star Frequency Astronomy and Astrophysics 274 3 870 Bibcode 1993A amp A 274 870C Andrillat A Jaschek M Jaschek C July 1990 A survey of Be stars in the infrared II Determination of envelope dimensions Astronomy and Astrophysics Supplement Series 84 1 11 28 Bibcode 1990A amp AS 84 11A The Colour of Stars Australia Telescope Outreach and Education Commonwealth Scientific and Industrial Research Organisation December 21 2004 archived from the original on 2012 03 18 retrieved 2012 01 16 de Zeeuw P T et al January 1999 A HIPPARCOS Census of the Nearby OB Associations The Astronomical Journal 117 1 354 399 arXiv astro ph 9809227 Bibcode 1999AJ 117 354D doi 10 1086 300682 S2CID 16098861External links editKaler James B SEGIN Epsilon Cassiopeiae University of Illinois Retrieved 2010 02 21 Retrieved from https en wikipedia org w index php title Epsilon Cassiopeiae amp oldid 1186943103, wikipedia, wiki, book, books, library,

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