21 Cancri

{{Starbox observe

| constell = Cancer

| epoch = J2000

| ra = {{RA|08|23|55.20829}}

| dec = {{DEC|+10|37|55.4169}}

| appmag_v = 6.08

}}

{{Starbox character

| Giant star

| class = M2III

| b-v = {{Val|1.507|0.004}}

| variable = suspected

}}

{{Starbox astrometry

| radial_v = 4.53

| prop_mo_ra = {{val|-0.843}}

| prop_mo_dec = {{val|-22.943}}

| parallax = 4.1258

| p_error = 0.0272

| parallax_footnote =

| absmag_v =

}}

{{Starbox detail

| mass =

| temperature = 3,885

| radius = 53

| luminosity = 587

}}

{{Starbox catalog

| names = {{odlist | BD=+11°1830 | HD=70734 | HIP=41163 | HR=3290 | SAO=97788 | NSV=17875 }}

}}

{{Starbox reference

| Simbad = 21+Cancri

}}

21 Cancri is a double star in the northern zodiac constellation of Cancer. It is just visible to the naked eye as a dim, red-hued star with an apparent visual magnitude of 6.08. The star is located around 791 light years away from the Sun, based on parallax. It is moving further from the Earth with a heliocentric radial velocity of 35 km/s.

The brighter component is an aging red giant with a stellar classification of M2III. It is currently on the asymptotic giant branch, indicating this is a highly evolved star that has exhausted both its core hydrogen and core helium. This is a suspected variable star. It has expanded to 53 times the radius of the Sun and is radiating 587 times the Sun's luminosity from its swollen photosphere at an effective temperature of 3,885 K. A 9th magnitude companion star is located one arc second away.

References

{{reflist|refs=

{{cite journal

| title=XHIP: An extended hipparcos compilation

| last1=Anderson | first1=E. | last2=Francis | first2=Ch.

| journal=Astronomy Letters

| volume=38 | issue=5 | pages=331 | year=2012

| bibcode=2012AstL...38..331A | arxiv=1108.4971

| doi=10.1134/S1063773712050015 | s2cid=119257644 }}

{{cite journal|bibcode=1985ApJS...59...95A|title=Visual multiples. VIII. 1000 MK types|journal=The Astrophysical Journal Supplement Series|volume=59|pages=95|last1=Abt|first1=H. A.|year=1985|doi=10.1086/191064|doi-access=free}}

{{cite journal|bibcode=2002yCat.2237....0D|title=VizieR On-line Data Catalog: Catalogue of Stellar Photometry in Johnson's 11-color system|journal=VizieR On-line Data Catalog|last1=Ducati|first1=J. R.|year=2002|volume=2237 }}

{{cite journal|bibcode=2009yCat....102025S|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)|journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S|volume=1|pages=B/GCVS|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}

{{cite journal|bibcode=1992AJ....104..275E|title=Asymptotic Giant Branch Stars Near the Sun|journal=The Astronomical Journal|volume=104|pages=275|last1=Eggen|first1=Olin J.|year=1992|doi=10.1086/116239}}

}}

Category:M-type giants

Category:Suspected variables

Category:Cancer (constellation)

Category:Binary stars

Cancri, 21

Category:Durchmusterung objects

070734

041163

3290