HD 4732
{{Short description|Star in the constellation Cetus}}
{{Starbox begin
| name = HD 4732
| image = Cetus_constellation_map.svg
}}
{{Starbox observe
| epoch = J2000.0
| constell = Cetus
| dec = {{DEC|−24|08|11.9907}}
}}
{{Starbox character
| r-i =
| variable =
}}
{{Starbox astrometry
| radial_v = {{val|24.81|0.12}}
| prop_mo_ra = 81.165
| prop_mo_dec = –56.642
| parallax = 18.1441
| p_error = 0.0422
}}
{{Starbox detail
| metal_fe = {{val|-0.01|0.05|0.11}}
| rotation =
}}
{{Starbox catalog
| names = {{odlist | ADS=679 | CD=-24 345 | HD=4732 | HIP=3834 | HR=228 | SAO=166602 | 2MASS=J00491393-2408119}}
}}
{{Starbox reference
| Simbad = HD+4732 | sn = A
| Simbad2 = HD+4732B | sn2 = B
| NSTED = HD-4732
}}
{{Starbox end}}
HD 4732 is a red giant star of magnitude 5.9 located in the constellation Cetus. It is 180 light-years from the Solar System.
The star is classified by some sources as a K-type giant and by others as a subgiant. It has an absolute magnitude of 2.09, and its radial velocity indicates that the star is moving away from the Solar System. There is a companion star about half the mass of the Sun at a separation of 8.77 arcseconds, corresponding to 481 AU.
Observation
HD 4732 is located in the celestial Southern Hemisphere, although it can be observed from most regions of the Earth. Near Antarctica the star is circumpolar, while it is always below the horizon near the Arctic. Its magnitude of 5.9 places it at the limit of visibility to the naked eye, so observing this star with the naked eye is possible with a clear sky and no Moon.
The best time to observe this star in the evening sky falls in the months between September and February, and from both hemispheres the period of visibility remains approximately the same, thanks to the star's position not far from the celestial equator.
Planetary system
In November 2012, a two-planet system was announced orbiting around this star from radial velocity measurements at Okayama Astrophysical Observatory and Australian Astronomical Observatory. The planetary system has two giant planets with identical minimum masses of 2.4 times that of Jupiter with orbital periods of 360 days and 2732 days. If the planets are coplanar and prograde, the true masses of the planets cannot exceed 28 times that of Jupiter based on dynamical stability analysis for the system. The planetary parameters were updated in 2023.
The planetary system of HD 4732 was found to be stable by a 2019 study.{{cite journal |last1=Agnew |first1=Matthew T |last2=Maddison |first2=Sarah T |last3=Horner |first3=Jonathan |last4=Kane |first4=Stephen R |title=Predicting multiple planet stability and habitable zone companions in the TESS era |journal=Monthly Notices of the Royal Astronomical Society |date=June 2019 |volume=485 |issue=4 |pages=4703–4725 |doi=10.1093/mnras/stz345 |url=https://academic.oup.com/mnras/article/485/4/4703/5307090 |access-date=28 April 2020|doi-access=free |arxiv=1901.11297 }}
{{OrbitboxPlanet begin
}}
{{OrbitboxPlanet
| exoplanet = b
| mass = {{val|1.986|0.156|0.154|p=≥}}
| period = {{val|371.74|0.72|1.86}}
| semimajor = {{val|1.129|0.001|0.004}}
| eccentricity = {{val|0.266|0.081|0.068}}
}}
{{OrbitboxPlanet
| exoplanet = c
| mass = {{val|3.365|0.116|0.269|p=≥}}
| period = {{val|3184.20|58.12|57.60}}
| semimajor = {{val|4.725|0.057}}
| eccentricity = {{val|0.187|0.034|0.066}}
}}
{{Orbitbox end}}
See also
References
{{reflist|refs=
{{Cite Gaia DR3|2345744256120965504}}
| url=http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HR+228
| title =Pulsating variable Star
| publisher=Centre de Données astronomiques de Strasbourg
| work=SIMBAD
| access-date=2012-07-13}}
| url=http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-out.add=.&-source=5050&-corr=PK=HR&-out.max=9999&HR=228
| title =VizieR Detailed Page
| access-date=2012-07-13}}
{{cite journal |last1=Mugrauer |first1=M. |date=December 2019 |title=Search for stellar companions of exoplanet host stars by exploring the second ESA-Gaia data release |journal=Monthly Notices of the Royal Astronomical Society |volume=490 |issue=4 |pages=5088–5102 |doi=10.1093/mnras/stz2673 |doi-access=free |bibcode=2019MNRAS.490.5088M}}
{{cite journal |last1=Teng |first1=Huan-Yu |last2=Sato |first2=Bun'ei |display-authors=etal |date=August 2023 |title=Revisiting planetary systems in the Okayama Planet Search Program: A new long-period planet, RV astrometry joint analysis, and a multiplicity-metallicity trend around evolved stars |journal=Publications of the Astronomical Society of Japan |volume=75 |issue=6 |pages=1030–1071 |doi=10.1093/pasj/psad056 |arxiv=2308.05343 |bibcode=2023PASJ...75.1030T}}
}}
External links
- [http://simbad.u-strasbg.fr/simbad/sim-id?Ident=HD+4732&submit=display+all+measurements Star Simbad data from the archive]
- [http://vizier.u-strasbg.fr/viz-bin/VizieR-S?CCDM+J00492-2408A Data on the star system from the site Vizier]
{{Stars of Cetus}}
{{DEFAULTSORT:HD 4732}}