Iota Cancri

ι Cancri
Location of ι Cancri (circled)
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Cancer[1]
ι Cnc A
Right ascension 08h 46m 41.820s[2]
Declination +28° 45′ 35.62″[2]
Apparent magnitude (V) 4.03[1]
ι Cnc B
Right ascension 08h 46m 39.980s[3]
Declination +28° 45′ 54.21″[3]
Apparent magnitude (V) 6.58[4]
Characteristics
ι Cnc A
Spectral type G8IIIa Ba0.2[5]
B−V color index 1.007±0.015[1]
ι Cnc B
Spectral type A2V[6]
B−V color index 0.051±0.008[4]
Astrometry
ι Cnc A
Radial velocity (Rv)15.74±0.13[7] km/s
Proper motion (μ) RA: −22.070 mas/yr[2]
Dec.: −43.699 mas/yr[2]
Parallax (π)9.4124±0.1621 mas[2]
Distance347 ± 6 ly
(106 ± 2 pc)
Absolute magnitude (MV)−0.79[8]
ι Cnc B
Radial velocity (Rv)25.00±1.5[9] km/s
Proper motion (μ) RA: −24.397 mas/yr[3]
Dec.: −44.250 mas/yr[3]
Parallax (π)9.6720±0.0362 mas[3]
Distance337 ± 1 ly
(103.4 ± 0.4 pc)
Details
ι Cnc A
Mass2.376±0.011[10] M☉
Radius21[7] R☉
Luminosity204[7] L☉
Surface gravity (log g)2.5[7] cgs
Temperature4,954[8] K
Metallicity [Fe/H]−0.14[7] dex
ι Cnc B
Mass2.113±0.035[10] M☉
Radius1.94±0.05[11] R☉
Luminosity24.9±1.2[11] L☉
Surface gravity (log g)4.23±0.06[11] cgs
Temperature9,259±139[11] K
Rotational velocity (v sin i)170[12] km/s
Age263[13] Myr
Other designations
ι Cancri, 48 Cancri, WDS J08467+2846[14]
Iota Cancri A: NSV 4238, BD+29°1824, FK5 328, GC 12083, HD 74739, HIP 43103, HR 3475, SAO 80416[14]
Iota Cancri B: BD+29°1823, GC 12080, HD 74738, HIP 43100, HR 3474, SAO 80415, TIC 117355623[15]
Database references
SIMBADdata

Iota Cancri is a double star in the constellation Cancer. Its name is a Bayer designation that is Latinized from ι Cancri, and abbreviated Iota Cnc or ι Cnc. The brighter component is located at a distance of approximately 347 light-years (106 pc) from Earth based on parallax measurements, and is drifting further away with a line of sight velocity of 16 km/s.[7]

The two stars of ι Cancri are separated by 30.5 arcseconds as of 2019, corresponding to a projected separation of 3,236 AU (0.05 ly).[10] Although no orbit has been derived, the pair show a large common proper motion and are assumed to be gravitationally related.[16]

Properties

The brighter star, ι Cancri A, is a yellow G-type giant with a stellar classification of G8IIIa Ba0.2[5] and an apparent visual magnitude of +4.03.[1] The suffix notation 'Ba0.2' indicates this is a mild barium star, thought to be caused by mass transfer of enriched material from an asymptotic giant branch star onto a less evolved companion. No such donor has been detected in the ι Cancri system, but it is assumed that there is an unseen white dwarf.[17]

This star has 2.4[10] times the mass of the Sun and has expanded to 21 times the Sun's radius.[7] It is radiating 204[7] times the Sun's luminosity from its enlarged photosphere at an effective temperature of 4,954 K.[8]

The fainter of the two stars, ι Cancri B, is a white A-type main-sequence star with a class of A2V[6] and an apparent magnitude of +6.58.[4] The star has 2.1[10] times the Sun's mass and 1.9 times the Sun's radius.[11] It is radiating 25 times the luminosity of the Sun from its photosphere at an effective temperature of 9,259 K.[11] With an estimated age of 263[13] million years, it is spinning rapidly with a projected rotational velocity of 170 km/s.[12] This is a shell star, surrounded by material expelled by its rapid rotation.[18]

References

  1. ^ a b c d 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. XHIP record for this object at VizieR.
  2. ^ a b c d 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.
  3. ^ a b c d 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.
  4. ^ a b c 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. XHIP record for this object at VizieR.
  5. ^ a b Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series. 71: 245. Bibcode:1989ApJS...71..245K. doi:10.1086/191373. S2CID 123149047.
  6. ^ a b Grenier, S.; et al. (1999). "Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS" (PDF). Astronomy and Astrophysics Supplement. 137 (3): 451. Bibcode:1999A&AS..137..451G. doi:10.1051/aas:1999489.
  7. ^ a b c d e f g h Massarotti, Alessandro; et al. (2008). "Rotational and Radial Velocities for a Sample of 761 HIPPARCOS Giants and the Role of Binarity". The Astronomical Journal. 135 (1): 209–231. Bibcode:2008AJ....135..209M. doi:10.1088/0004-6256/135/1/209.
  8. ^ a b c Kovtyukh, V. V.; et al. (2010). "Accurate luminosities for F-G supergiants from FeII/FeI line depth ratios". Monthly Notices of the Royal Astronomical Society. 408 (3): 1568. Bibcode:2010MNRAS.408.1568K. doi:10.1111/j.1365-2966.2010.17217.x.
  9. ^ Gontcharov, G. A. (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. S2CID 119231169.
  10. ^ a b c d e Jiménez-Esteban, F. M.; et al. (February 2019). "A Catalog of Wide Binary and Multiple Systems of Bright Stars from Gaia-DR2 and the Virtual Observatory". The Astronomical Journal. 157 (2): 78. arXiv:1901.03730. Bibcode:2019AJ....157...78J. doi:10.3847/1538-3881/aafacc. 78.
  11. ^ a b c d e f Stassun, Keivan G.; et al. (September 9, 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal. 158 (4): 138. arXiv:1905.10694. Bibcode:2019AJ....158..138S. doi:10.3847/1538-3881/ab3467. eISSN 1538-3881.
  12. ^ a b Royer, F.; et al. (2002). "Rotational velocities of A-type stars in the northern hemisphere. II. Measurement of v sin i". Astronomy and Astrophysics. 393 (3): 897–912. arXiv:astro-ph/0205255. Bibcode:2002A&A...393..897R. doi:10.1051/0004-6361:20020943. S2CID 14070763.
  13. ^ a b Takeda, Yoichi; et al. (2008). "Stellar Parameters and Elemental Abundances of Late-G Giants". Publications of the Astronomical Society of Japan. 60 (4): 781. arXiv:0805.2434. Bibcode:2008PASJ...60..781T. doi:10.1093/pasj/60.4.781. S2CID 16258166.
  14. ^ a b "iot Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2025-06-22.
  15. ^ "iot Cnc B". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2025-06-22.
  16. ^ Eggen, Olin J. (1994). "Photometry of F-K type bright giants and supergiants. 3: The luminosity, reddening, and heavy element abundance of GK stars". The Astronomical Journal. 107: 2184. Bibcode:1994AJ....107.2184E. doi:10.1086/117030.
  17. ^ Eggleton, P. P.; Tokovinin, A. A. (2008). "A catalogue of multiplicity among bright stellar systems". Monthly Notices of the Royal Astronomical Society. 389 (2): 869. arXiv:0806.2878. Bibcode:2008MNRAS.389..869E. doi:10.1111/j.1365-2966.2008.13596.x. S2CID 14878976.
  18. ^ Hauck, B.; Jaschek, C. (2000). "A-shell stars in the Geneva system". Astronomy and Astrophysics. 354: 157. Bibcode:2000A&A...354..157H.
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