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
Evolutionary stage main sequence[3]
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
SIMBADA
B

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]

Nomenclature

ι Cancri (Latinised to Iota Cancri) is the star's Bayer designation.

ι Cancri together with α Cancri were known in Arabic as Al Zubanāh, the claws (of the crab),[19] originating in translation of Ptolemy's Tetrabiblos.[20] This is the source of the modern name Acubens for α Cancri;[20] a 1971 NASA catalog of star names also used the name Zubanah for ι Cancri.[21]

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. Bibcode2012AstL...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 3.3 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.
  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. Bibcode2012AstL...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. Bibcode1989ApJS...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. Bibcode1999A&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. Bibcode2008AJ....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. Bibcode2010MNRAS.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. Bibcode2006AstL...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. Bibcode2019AJ....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. Bibcode2019AJ....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. Bibcode2002A&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. Bibcode2008PASJ...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. Bibcode1994AJ....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. Bibcode2008MNRAS.389..869E. 
  18. Hauck, B.; Jaschek, C. (2000). "A-shell stars in the Geneva system". Astronomy and Astrophysics 354: 157. Bibcode2000A&A...354..157H. 
  19. Allen, R. H. (1899), Star Names: Their Lore and Meaning, p. 111, https://penelope.uchicago.edu/Thayer/E/Gazetteer/Topics/astronomy/_Texts/secondary/ALLSTA/Cancer*.html 
  20. 20.0 20.1 "Acubens". IAU Working Group on Star Names. https://xing.fmi.uni-jena.de/mediawiki/index.php/Acubens. 
  21. Rhoads, Jack W. (November 15, 1971), Technical Memorandum 33-507-A Reduced Star Catalog Containing 537 Named Stars, Jet Propulsion Laboratory, California Institute of Technology, https://ntrs.nasa.gov/api/citations/19720005197/downloads/19720005197.pdf.