Astronomy:Iota Cancri

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Short description: Double star in the constellation Cancer
ι Cancri
Location of ι Cancri (circled)
Observation data
{{#ifeq:J2000.0|J2000.0 (ICRS)|Epoch J2000.0      Equinox J2000.0 (ICRS)| [[History:Epoch|Epoch J2000.0]]      [[Astronomy:Equinox (celestial coordinates)|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[2] mas/yr
Dec.: −43.699[2] mas/yr
Parallax (π)9.4124 ± 0.1621[2] mas
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
Dec.: −44.250 mas/yr
Parallax (π)9.6720 ± 0.0362[3] mas
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[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 astronomical unit|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

ι Cancri A (right) and B (Jeffrey Fisher)

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. ↑ 1.0 1.1 1.2 1.3 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A  XHIP record for this object at VizieR.
  2. ↑ 2.0 2.1 2.2 2.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  3. ↑ 3.0 3.1 3.2 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940  Gaia DR3 record for this source at VizieR.
  4. ↑ 4.0 4.1 4.2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A  XHIP record for this object at VizieR.
  5. ↑ 5.0 5.1 Keenan, Philip C.; McNeil, Raymond C. (1989). "The Perkins catalog of revised MK types for the cooler stars". Astrophysical Journal Supplement Series 71: 245. doi:10.1086/191373. Bibcode: 1989ApJS...71..245K. 
  6. ↑ 6.0 6.1 Grenier, S. et al. (1999). "Radial velocities. Measurements of 2800 B2-F5 stars for HIPPARCOS". Astronomy and Astrophysics Supplement 137 (3): 451. doi:10.1051/aas:1999489. Bibcode: 1999A&AS..137..451G. https://hal.archives-ouvertes.fr/hal-02053966/file/Grenier%20et%20al.%20-%201999%20-%20Radial%20velocities.%20Measurements%20of%202800%20B2-F5%20star.pdf. 
  7. ↑ 7.0 7.1 7.2 7.3 7.4 7.5 7.6 7.7 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. doi:10.1088/0004-6256/135/1/209. Bibcode: 2008AJ....135..209M. 
  8. ↑ 8.0 8.1 8.2 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. doi:10.1111/j.1365-2966.2010.17217.x. Bibcode: 2010MNRAS.408.1568K. 
  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. doi:10.1134/S1063773706110065. Bibcode: 2006AstL...32..759G. 
  10. ↑ 10.0 10.1 10.2 10.3 10.4 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. doi:10.3847/1538-3881/aafacc. 78. Bibcode: 2019AJ....157...78J. 
  11. ↑ 11.0 11.1 11.2 11.3 11.4 11.5 Stassun, Keivan G. (September 9, 2019). "The Revised TESS Input Catalog and Candidate Target List". The Astronomical Journal 158 (4): 138. doi:10.3847/1538-3881/ab3467. Bibcode: 2019AJ....158..138S. 
  12. ↑ 12.0 12.1 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. doi:10.1051/0004-6361:20020943. Bibcode: 2002A&A...393..897R. 
  13. ↑ 13.0 13.1 Takeda, Yoichi et al. (2008). "Stellar Parameters and Elemental Abundances of Late-G Giants". Publications of the Astronomical Society of Japan 60 (4): 781. doi:10.1093/pasj/60.4.781. Bibcode: 2008PASJ...60..781T. 
  14. ↑ 14.0 14.1 "iot Cnc". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=iot+Cnc. 
  15. ↑ "iot Cnc B". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=iot+Cnc+B. 
  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. doi:10.1086/117030. Bibcode: 1994AJ....107.2184E. 
  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. doi:10.1111/j.1365-2966.2008.13596.x. Bibcode: 2008MNRAS.389..869E. 
  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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