4 Canum Venaticorum
{{Short description|Binary star system in the constellation Canes Venatici}}
{{Starbox begin
| name = 4 Canum Venaticorum
}}
{{Starbox image
| image = 250px
| caption = A light curve for AI Canes Venaticorum, plotted from TESS data
}}
{{Starbox observe
| epoch = J2000
| constell = Canes Venatici
| dec = {{DEC|+42|32|33.8670}}
| appmag_v = +6.04 {{nowrap|5.89 to 6.15}}
}}
{{Starbox character
| type =
| class = F3 IV or F0 III
| u-b =
| variable = δ Sct
}}
{{Starbox astrometry
| parallax = 7.6829
| p_error = 0.0960
}}
{{Starbox orbit
| period_unitless = {{Val|124.44|0.03|u=days}}
| eccentricity = {{Val|0.311|0.003}}
| periastron = {{Val|2454605|10.3|ul=JD}}
| periarg = {{Val|70.2|0.7}}
| k1 = {{Val|13.24|0.05}}
}}
{{Starbox detail
| component1 = 4 CVn A
| mass = {{Val|1.0|–|2.0}}
| radius = {{Val|3.7|–|4.1}}
| luminosity = {{Val|295|3.6|3.2}}
| gravity = {{Val|3.30|0.35}}
| temperature = {{Val|6875|120|fmt=commas}}
| metal_fe = {{Val|−0.05|0.15}}
| rotational_velocity = {{Val|109|3}}
| age_gyr =
}}
{{Starbox catalog
| names = {{odlist | V=AI Canum Venaticorum | F=4 CVn | BD=+43°2218 | FK5=2993 | HD=107904 | HIP=60467 | HR=4715 | SAO=44155 | GC=16899 }}
}}
{{Starbox reference
| Simbad = 4+CVn
}}
{{Starbox end}}
4 Canum Venaticorum is a binary star system in the northern constellation of Canes Venatici, located around 425 light years away. It has the variable star designation AI Canum Venaticorum; 4 Canum Venaticorum is its Flamsteed designation. Its brightness varies from magnitude +5.89 to +6.15 with a period of 2.8 hours, which places it around the lower limit of visibility to the naked eye. This was found to be a binary by Schmid et al. in 2014, based on periodic, non-sinusoidal changes in its radial velocity. It is a single-lined spectroscopic binary with an orbital period of 124.4 days and an eccentricity of 0.31.
The primary component is an evolved F-type star with a stellar classification of F3 IV or F0 III, matching a subgiant or giant star, respectively. Roberta M. Humphreys first showed that the star's brightness varies, in 1966. It is a variable of the Delta Scuti class, displaying both radial and non-radial pulsations. The variable nature of this star was discovered by D. H. P. Jones and C. Margaret Haslam in 1966 at the suggestion of Olin J. Eggen, and it has become one of the best studied stars in its class. The radial pulsations have shown little if any variations between 1974 and 2012. However, the non-radial pulsations vary continuously in frequency over periods spanning decades. It is spinning rapidly with a rotation of at least one third of its critical velocity.
References
{{reflist|refs=
{{cite simbad | title=4 CVn | access-date=2018-07-25 }}
{{cite DR2|1535113503063938944}}
| last1=Humphreys | first1=Roberta M. | title=Photoelectric Observations of 4 Canum Venaticorum
| journal=Publications of the Astronomical Society of the Pacific | bibcode=1967PASP...79...78H
| date=February 1967 | volume=79 | issue=466 | pages=78-80 | doi=10.1086/128444
| url=https://articles.adsabs.harvard.edu/pdf/1967PASP...79...78H | access-date=6 January 2025}}
| last1=Samus | first1=N. N. | last2=Kazarovets | first2=E. V.
| last3=Durlevich | first3=O. V. | last4=Kireeva | first4=N. N.
| last5=Pastukhova | first5=E. N. | display-authors=1
| title=General Catalogue of Variable Stars
| version=5.1 | journal=Astronomy Reports
| year=2017 | volume=61 | issue=1 | pages=80–88
| doi=10.1134/S1063772917010085 | bibcode=2017ARep...61...80S | s2cid=125853869 | postscript=. }}
| 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 | doi=10.1134/S1063773712050015
| arxiv=1108.4971 | s2cid=119257644 | postscript=. }}
| title=A new delta Scuti variable
| last1=Jones | first1=D. H. P. | last2=Haslam | first2=C. M.
| journal=The Observatory
| volume=86 | pages=34 | date=February 1966
| bibcode=1966Obs....86...34J | postscript=. }}
| title=Nonradial and radial period changes of the δ Scuti star 4 CVn. II. Systematic behavior over 40 years
| last1=Breger | first1=M. | last2=Montgomery | first2=M. H.
| last3=Lenz | first3=P. | last4=Pamyatnykh | first4=A. A.
| display-authors=1 | journal=Astronomy & Astrophysics
| volume=599 | id=A116 | pages=8 | date=March 2017
| doi=10.1051/0004-6361/201629797
| bibcode=2017A&A...599A.116B
| arxiv=1612.06827 | s2cid=55127114 | postscript=. }}
| title=Discovery of binarity, spectroscopic frequency analysis, and mode identification of the δ Scuti star 4 CVn
| last1=Schmid | first1=V. S. | last2=Themeßl | first2=N.
| last3=Breger | first3=M. | last4=Degroote | first4=P.
| last5=Aerts | first5=C. | last6=Beck | first6=P. G.
| last7=Tkachenko | first7=A. | last8=Van Reeth | first8=T.
| last9=Bloemen | first9=S. | last10=Debosscher | first10=J.
| last11=Castanheira | first11=B. G. | last12=McArthur | first12=B. E.
| last13=Pápics | first13=P. I. | last14=Fritz | first14=V.
| last15=Falcon | first15=R. E. | display-authors=1
| journal=Astronomy & Astrophysics
| volume=570 | id=A33 | pages=17 | date=October 2014
| doi=10.1051/0004-6361/201423669 | bibcode=2014A&A...570A..33S
| arxiv=1407.4257 | s2cid=36767234 | postscript=. }}
| title=The Age Range of Hyades Stars
| last1=Eggen | first1=Olin J. | postscript=.
| journal=The Astronomical Journal
| volume=116 | issue=1 | pages=284–292 | date=July 1998
| doi=10.1086/300413 | bibcode=1998AJ....116..284E | doi-access=free }}
| last1=Morgan | first1=W. W. | last2=Abt | first2=H. A.
| title=The spectral classification of the F stars of intermediate luminosity
| journal=Astronomical Journal
| volume=77 | pages=35–37 | date=February 1972
| doi=10.1086/111242 | bibcode=1972AJ.....77...35M | doi-access=free }}
| last1=Appenzeller | first1=Immo | postscript=.
| title=MK Spectral Types for 185 Bright Stars
| journal=Publications of the Astronomical Society of the Pacific
| volume=79 | issue=467 | page=102 | date=April 1967
| doi=10.1086/128449 | bibcode=1967PASP...79..102A | doi-access=free }}
}}
{{Stars of Canes Venatici}}
{{DEFAULTSORT:4 Canum Venaticorum}}
Category:Delta Scuti variables