Eta Persei


η Persei
Perseus constellation map.svg
Red circle.svg
Location of η Per (circled)
Observation data
Epoch J2000      Equinox J2000
Constellation Perseus
Right ascension 02h 50m 41.766s[1]
Declination +55° 53′ 43.7876″[1]
Apparent magnitude (V) 3.79[2]
Spectral type K3 Ib[3]
U−B color index +1.90[2]
B−V color index +1.69[2]
Radial velocity (Rv)−1.07 ± 0.27[4] km/s
Proper motion (μ) RA: +16.574[1] mas/yr
Dec.: −12.709[1] mas/yr
Parallax (π)4.2061 ± 0.3744[1] mas
Distance780 ± 70 ly
(240 ± 20 pc)
Absolute magnitude (MV)−4.29[5]
Radius134[6] R
Luminosity4,130[6] L
Temperature3,986±170[6] K
Rotational velocity (v sin i)5.8[3] km/s
Other designations
Miram, η Persei, η Per, Eta Per, 15 Persei, BD+55 714, CCDM J02506+5553A, FK5 99, GC 3390, HD 17506, HIP 13268, HR 834, IDS 02434+5529 A, PPM 28039, SAO 23655, WDS J02507+5554A
Database references

Eta Persei (η Persei, abbreviated Eta Per, η Per), is a binary star and the 'A' component of a triple star system (the 'B' component is the star HD 237009)[7] in the constellation of Perseus. It is approximately 1331 light-years away from Earth.

The two components of Eta Persei itself are designated Eta Persei A (officially named Miram /ˈmræm/, a recent name for the system)[8] and B.


η Persei in optical light

η Persei (Latinised to Eta Persei) is the binary star's Bayer designation. The designations of its two components as Eta Persei A and B derive from the convention used by the Washington Multiplicity Catalog (WMC) for multiple star systems, and adopted by the International Astronomical Union (IAU).[9]

Eta Persei mysteriously gained the named Miram in the 20th Century, though no source is known.[10][11] In 2016, the IAU organized a Working Group on Star Names (WGSN)[12] to catalog and standardize proper names for stars. The WGSN decided to attribute proper names to individual stars rather than entire multiple systems.[13] It approved the name Miram for the component Eta Persei A on 5 September 2017 and it is now so included in the List of IAU-approved Star Names.[8]

This star, together with Delta Persei, Psi Persei, Sigma Persei, Alpha Persei and Gamma Persei has been called the Segment of Perseus.[11]

In Chinese, 天船 (Tiān Chuán), meaning Celestial Boat, refers to an asterism consisting of Eta Persei, Gamma Persei, Alpha Persei, Psi Persei, Delta Persei, 48 Persei, Mu Persei and HD 27084. Consequently, the Chinese name for Eta Persei itself is 天船一 (Tiān Chuán yī, English: the First Star of Celestial Boat.)[14]


Eta Persei A belongs to spectral class K3 and has an apparent magnitude of +3.76. It radiates with 35,000 times the luminosity of the Sun.[15]


  1. ^ a b c d e 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.
  2. ^ a b c Ducati, J. R. (2002). "VizieR Online Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system". CDS/ADC Collection of Electronic Catalogues. 2237. Bibcode:2002yCat.2237....0D.
  3. ^ a b De Medeiros, J. R.; Udry, S.; Burki, G.; Mayor, M. (2002). "A catalog of rotational and radial velocities for evolved stars. II. Ib supergiant stars". Astronomy and Astrophysics. 395: 97–98. arXiv:1312.3474. Bibcode:2002A&A...395...97D. doi:10.1051/0004-6361:20021214.
  4. ^ Famaey, B.; Jorissen, A.; Luri, X.; Mayor, M.; Udry, S.; Dejonghe, H.; Turon, C. (2005). "Local kinematics of K and M giants from CORAVEL/Hipparcos/Tycho-2 data. Revisiting the concept of superclusters". Astronomy and Astrophysics. 430: 165. arXiv:astro-ph/0409579. Bibcode:2005A&A...430..165F. doi:10.1051/0004-6361:20041272. S2CID 17804304.
  5. ^ Ryon, Jenna; Shetrone, Matthew D.; Smith, Graeme H. (2009). "Comparing the Ca ii H and K Emission Lines in Red Giant Stars". Publications of the Astronomical Society of the Pacific. 121 (882): 842. arXiv:0907.3346. Bibcode:2009PASP..121..842R. doi:10.1086/605456. S2CID 17821279.
  6. ^ a b c Messineo, M.; Brown, A. G. A. (2019). "A Catalog of Known Galactic K-M Stars of Class I Candidate Red Supergiants in Gaia DR2". The Astronomical Journal. 158 (1): 20. arXiv:1905.03744. Bibcode:2019AJ....158...20M. doi:10.3847/1538-3881/ab1cbd. S2CID 148571616.
  7. ^ "Washington Double Star Catalog". United States Naval Observatory. Archived from the original on 14 February 2011. Retrieved 2 January 2018.
  8. ^ a b "Naming Stars". Retrieved 16 December 2017.
  9. ^ Hessman, F. V.; Dhillon, V. S.; Winget, D. E.; Schreiber, M. R.; Horne, K.; Marsh, T. R.; Guenther, E.; Schwope, A.; Heber, U. (2010). "On the naming convention used for multiple star systems and extrasolar planets". arXiv:1012.0707 [astro-ph.SR].
  10. ^ Kaler, Jim. "Eta Persei". Retrieved 2017-02-11.
  11. ^ a b 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.
  12. ^ "IAU Working Group on Star Names (WGSN)". Retrieved 22 May 2016.
  13. ^ "WG Triennial Report (2015-2018) - Star Names" (PDF). p. 5. Retrieved 2018-07-14.
  14. ^ (in Chinese) AEEA (Activities of Exhibition and Education in Astronomy) 天文教育資訊網 2006 年 7 月 11 日
  15. ^ Mallik, Sushma V. (December 1999), "Lithium abundance and mass", Astronomy and Astrophysics, 352: 495–507, Bibcode:1999A&A...352..495M