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15 Cancri

{{Short description|Star in the constellation Cancer}}

{{Starbox begin

| name = 15 Cancri

}}

{{Starbox image

| image = 250px

| caption = A light curve for BM Cancri, plotted from TESS data

}}

{{Starbox observe

| epoch = J2000.0

| constell = Cancer

| ra = {{RA|08|13|08.87009}}

| dec = {{DEC|+29|39|23.5777}}

| appmag_v = 5.53 - 5.65

}}

{{Starbox character

| class = A0:V:spSiSr

| r-i =

| v-r =

| b-v = {{Val|−0.073|0.002}}

| u-b =

| variable = α2 CVn

}}

{{Starbox astrometry

| radial_v = {{val|25.0|0.8}}

| prop_mo_ra = −12.959

| prop_mo_dec = −22.232

| parallax = 3.3279

| p_error = 0.2458

| parallax_footnote =

| absmag_v = −0.97

}}

{{Starbox orbit

| reference =

| primary = 15 Cancri A

| name = 15 Cancri B

| period_unitless = {{val|635.73|0.53}} days

| axis =

| axis_unitless =

| eccentricity = {{val|0.55|0.08}}

| inclination =

| node =

| periastron = {{val|2422045|18}}

| periarg =

| periarg_primary = {{val|196|13}}

| k1 = {{val|9.6|1.1}}

| k2 =

}}

{{Starbox detail

| component1 = 15 Cnc A

| mass =

| radius =

| luminosity = 327.24

| gravity = {{val|3.22|0.2}}

| temperature = {{val|10080|200|fmt=commas}}

| metal_fe =

| rotation =

| rotational_velocity = 25

| age_gyr =

}}

{{Starbox catalog

| names = {{odlist | V=BM Cnc | F=15 Cnc | BD=+30°1664 | HD=68351 | HIP=40240 | HR=3215 | SAO= | GSC=01939-01462 }}

}}

{{Starbox reference

| Simbad = HD+68351

}}

{{Starbox end}}

15 Cancri is an α2 CVn-type variable star in the zodiac constellation of Cancer, located around 980 light years away. It has the variable star designation BM Cancri (BM Cnc); 15 Cancri (15 Cnc) is the Flamsteed designation. This system is visible to the naked eye as a faint, white-hued star with an apparent visual magnitude of about 5.6. It is moving away from the Earth with a heliocentric radial velocity of 25 km/s.

Radial velocity measurements taken at the Dominion Astrophysical Observatory in Victoria, British Columbia Canada in 1918 and 1919 led to the determination that 15 Cancri is a single-lined spectroscopic binary system. The first orbit was calculated in 1973 by Helmut Abt and Michael Snowden with a period of 585 days however later measurements showed that the orbital period was 635 days.

15 Cancri A, the visible component, is an Ap star, a chemically peculiar star with an over-abundance of iron peak elements, particularly silicon, chromium, and strontium, in its spectrum.

Like all Ap stars, 15 Cancri has a strong magnetic field. This magnetic field varies as it rotates and in 1968 the visual brightness of the star was shown to vary regularly over about four days. 15 Cancri was given the variable star designation BM Cancri in 1972 as a member of the α2 CVn class of variable stars. The period has since been measured more accurately at {{val|3.3095|ul=days}}, believed to be the rotational period of the star.

Notes

{{reflist|group="note"|refs=

An alternate period of 475 days is possible but less likely.

}}

References

{{Reflist|refs=

{{Cite Gaia DR2|876666120047998592}}

{{cite web |title=MAST: Barbara A. Mikulski Archive for Space Telescopes |url=https://mast.stsci.edu/portal/Mashup/Clients/Mast/Portal.html |publisher=Space Telescope Science Institute |access-date=8 December 2021}}

{{cite journal|bibcode=1972IBVS..705....1M|title=New Southern Variable Stars|journal=Information Bulletin on Variable Stars|volume=705|pages=1|last1=Martins|first1=D. H.|year=1972}}

{{cite journal|doi=10.1086/149815|title=Photometric behavior of magnetic stars|journal=The Astrophysical Journal|volume=154|pages=945|year=1968|last1=Stepien|first1=K.|bibcode=1968ApJ...154..945S}}

{{cite journal|doi=10.1111/j.1365-2966.2011.20090.x|title=A photometric study of chemically peculiar stars with the STEREO satellites - I. Magnetic chemically peculiar stars★|journal=Monthly Notices of the Royal Astronomical Society|volume=420|issue=1|pages=757–772|year=2012|last1=Wraight|first1=K. T.|last2=Fossati|first2=L.|last3=Netopil|first3=M.|last4=Paunzen|first4=E.|last5=Rode-Paunzen|first5=M.|last6=Bewsher|first6=D.|last7=Norton|first7=A. J.|last8=White|first8=Glenn J.|doi-access=free |bibcode=2012MNRAS.420..757W|arxiv=1110.6283|s2cid=14811051}}

{{cite journal|doi=10.1051/0004-6361/200810788|title=Catalogue of Ap, Hg Mn and Am stars|journal=Astronomy & Astrophysics|volume=498|issue=3|pages=961–966|year=2009|last1=Renson|first1=P.|last2=Manfroid|first2=J.|doi-access=free|bibcode=2009A&A...498..961R}}

{{cite journal

| title=XHIP: An extended hipparcos compilation

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

| journal=Astronomy Letters | arxiv=1108.4971

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

| bibcode=2012AstL...38..331A | doi=10.1134/S1063773712050015 | s2cid=119257644 }}

{{cite journal | title=The Binary Frequency for AP Stars | last1=Abt | first1=Helmut A. | last2=Snowden | first2=Michael S. | journal=Astrophysical Journal Supplement | volume=25 | pages=137–162 | year=1973 | bibcode=1973ApJS...25..137A | doi=10.1086/190265 }}

{{cite journal | title=Project VeSElkA: Analysis of Balmer Line Profiles of Slowly Rotating Chemically Peculiar Stars | last1=Khalack | first1=V. | last2=LeBlanc | first2=F. | journal=The Astronomical Journal | volume=150 | issue=1 | at=2 | year=2015 | arxiv=1505.08158 | bibcode=2015AJ....150....2K | doi=10.1088/0004-6256/150/1/2 | s2cid=118283214 }}

{{cite journal | title=Fourth list of spectroscopic binaries | last1=Plaskett | first1=J. S. | last2=Harper | first2=W. E. | last3=Young | first3=R. K. | display-authors=1 | journal=Journal of the Royal Astronomical Society of Canada | year=1919 | volume=13 | pages=372–378 | bibcode=1919JRASC..13..372P }}

SIMBAD, [https://archive.today/20121210203737/http://simbak.cfa.harvard.edu/simbad/sim-basic?Ident=15+Cancri&submit=SIMBAD+search 15 Cancri] (accessed 2012 March 20)

{{cite journal | title=Radial velocities of northern Mercury stars | last1=Stickland | first1=D. J. | last2=Weatherby | first2=J. | journal=Astronomy and Astrophysics Supplement Series | volume=57 | pages=55–67 | year=1984 | bibcode=1984A&AS...57...55S }}

{{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|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}

{{cite journal|bibcode=1995ApJS...99..135A|title=The Relation between Rotational Velocities and Spectral Peculiarities among A-Type Stars|journal=Astrophysical Journal Supplement |volume=99|pages=135|last1=Abt|first1=Helmut A.|last2=Morrell|first2=Nidia I.|year=1995|doi=10.1086/192182|doi-access=free}}

}}

{{Stars of Cancer}}

{{DEFAULTSORT:15 Cancri}}

Category:Cancer (constellation)

Category:Alpha2 Canum Venaticorum variables

Category:Ap stars

Category:A-type main-sequence stars

Category:Spectroscopic binaries

Cancri, 15

Cancri, BM

Category:Durchmusterung objects

068351

3215

040240