2 Centauri

{{Starbox image

| image = 250px

| caption = A light curve for V806 Centauri. The main plot shows the long term variability from Hipparcos data, and the inset plot shows the variability over the 26.5 day period, using data from Tabur et al. (2009). The green curve shows the best-fit sine wave, which has an amplitude of 18 millimagnitudes.

}}

{{Starbox observe

| epoch= J2000.0

| constell = Centaurus

| ra = {{RA|13|49|26.72175}}

| dec = {{DEC|−34|27|02.7929}}

| appmag_v = {{nowrap|4.19 (4.16–4.26)}}

}}

{{Starbox character

| class = M5 III

| b-v = +1.49

| u-b = +1.44

| variable = SRb

}}

{{Starbox astrometry

| radial_v = {{Val|+40.7|0.7}}

| prop_mo_ra = {{Val|−41.68|0.23}}

| prop_mo_dec = {{Val|−59.77|0.18}}

| parallax = 17.82

| p_error = 0.21

| parallax_footnote =

| absmag_v = +0.51

}}

{{Starbox detail

| source =

| mass =

| radius = 82.4{{Cite journal |last1=Wood |first1=Brian E. |last2=Harper |first2=Graham M. |last3=Müller |first3=Hans-Reinhard |date=May 2024 |title=Resolving Red Giant Winds with the Hubble Space Telescope* |journal=The Astrophysical Journal |language=en |volume=967 |issue=2 |pages=120 |doi=10.3847/1538-4357/ad401f |doi-access=free |issn=0004-637X|arxiv=2404.15086 }}

| luminosity = 71.96

| temperature = 3,398

| metal_fe =

| gravity =

| rotational_velocity =

| age_gyr =

}}

{{Starbox catalog

| names = {{odlist | V=V806 Cen | B=g Centauri | F=2 Cen | CD=−33°9358 | HD=120323 | HIP=67457 | HR=5192 | SAO=204875 | GC=18666 }}

}}

{{Starbox reference

| Simbad = HD+120323

}}

2 Centauri is a single star in the southern constellation of Centaurus, located approximately 183 light-years from Earth. It has the Bayer designation g Centauri; 2 Centauri is the Flamsteed designation. This object is visible to the naked eye as faint, red-hued star with an apparent visual magnitude of 4.19. It is moving away from the Earth with a heliocentric radial velocity of +41 km/s. The star is a member of the HR 1614 supercluster.

This is an evolved red giant star with a stellar classification of M5 III. In 1951, Alan William James Cousins announced that the star, then called g Centauri, is a variable star. It was given its variable star designation, V806 Centauri, in 1978. It is classified as a semiregular variable star and its brightness varies from magnitude +4.16 to +4.26 with a period of 12.57 days. The star has around 70 times the Sun's radius and is radiating 72 times the Sun's luminosity from its enlarged photosphere at an effective temperature of {{val|3398|ul=K|fmt=commas}}.

References

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{{cite journal |last1=Kholopov |first1=P. N. |last2=Kukarkina |first2=N. P. |last3=Perova |first3=N. B. |title=63rd Name-List of Variable Stars |journal=Information Bulletin on Variable Stars |bibcode=1978IBVS.1414....1K |date=April 1978 |volume=1414 |pages=1–10 |url=https://ibvs.konkoly.hu/pub/ibvs/1401/1414.pdf |access-date=16 January 2025}}

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{{cite journal |last1=Tabur |first1=V. |last2=Bedding |first2=T. R. |last3=Kiss |first3=L. L. |last4=Moon |first4=T. T. |last5=Szeidl |first5=B. |last6=Kjeldsen |first6=H. |title=Long-term photometry and periods for 261 nearby pulsating M giants |journal=Monthly Notices of the Royal Astronomical Society |year=2009 |volume=400 |issue=4 |pages=1945–1961 |doi=10.1111/j.1365-2966.2009.15588.x |bibcode=2009MNRAS.400.1945T |doi-access=free |arxiv=0908.3228 }}

{{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}}

}}

Category:M-type giants

Category:Asymptotic-giant-branch stars

Category:Semiregular variable stars

Category:Centaurus

Centauri, g

Category:Durchmusterung objects