Astronomy:Beta Caeli
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| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Caelum |
| Right ascension | 04h 42m 03.482s[1] |
| Declination | −37° 08′ 39.59″[1] |
| Apparent magnitude (V) | 5.04[2] |
| Characteristics | |
| Spectral type | F3 V[3] or F3 IV[4] |
| U−B color index | +0.01[2] |
| B−V color index | +0.38[2] |
| Astrometry | |
| Radial velocity (Rv) | 27.47±0.24[1] km/s |
| Proper motion (μ) | RA: +42.561[1] mas/yr Dec.: +212.705[1] mas/yr |
| Parallax (π) | 34.6088 ± 0.0531[1] mas |
| Distance | 94.2 ± 0.1 ly (28.89 ± 0.04 pc) |
| Absolute magnitude (MV) | +2.64[5] |
| Orbit[6] | |
| Primary | A |
| Companion | B |
| Period (P) | 7.5 yr |
| Semi-major axis (a) | 4.6 AU |
| Eccentricity (e) | 0.6 |
| Inclination (i) | 27 or 153° |
| Longitude of the node (Ω) | 151° |
| Argument of periastron (ω) (secondary) | 38° |
| Details | |
| β Cae A | |
| Mass | 1.482±0.040[1] M☉ |
| Radius | 1.902+0.001 −0.004[1] R☉ |
| Luminosity | 6.615+0.020 −0.019[1] L☉ |
| Surface gravity (log g) | 3.981+0.003 −0.002[1] cgs |
| Temperature | 6,665.7+1.6 −1.4[1] K |
| Metallicity | Template:M/H[3] |
| Rotation | 0.8669±0.0013[6] days |
| Rotational velocity (v sin i) | 97.5±4.9[5] km/s |
| Age | 0.2 or 1.17[6] Gyr 1.941±0.307[1] Gyr |
| β Cae B | |
| Mass | 0.08 or 0.2[6] M☉ |
| Temperature | 3,593±160[6] K |
| Other designations | |
| Database references | |
| SIMBAD | data |
Beta Caeli is a star with an orbiting companion in the southern constellation of Caelum. Its name is a Bayer designation that is Latinized from β Caeli, and abbreviated Beta Cae or β Cae. This star is dimly visible to the naked eye, having an apparent visual magnitude of 5.04.[2] Based upon an annual parallax shift of 34.6 mas as seen from Earth,[1] it is located at a distance of 94 light-years (29 pc). The star is moving away from the Sun with a radial velocity of +27.5 km/s.[1]
Characteristics
Beta Caeli is a probable single-lined spectroscopic binary system, meaning only the spectral lines of the visible component can be seen.[8] This primary component has a stellar classification of F3 V[3] or F3 IV,[4] indicating it is either an F-type main-sequence star or a somewhat more evolved subgiant star, respectively. It has an estimated 1.5 times the mass of the Sun and about 1.9 times the Sun's radius.[1] The star is 200 million[6] to two billion years old[1] and has a high rate of spin with a projected rotational velocity of around 97.5 km/s.[5] It is radiating 6.6 times the luminosity of the Sun from its photosphere[1] at an effective temperature of 6,666 K.[1] Based on the amount of iron detected, the abundance of elements with mass greater than helium is lower than in the Sun.[3]
The low-mass companion is orbiting about 5 astronomical unit|AU from the primary, with an orbital period of around seven years. Its exact mass is uncertain; an orbital solution suggest it is close to the brown dwarf regime at around 0.08 M☉, but models of stellar atmospheres suggest a higher mass of 0.2 M☉.[6] It was first detected in 2017 and was believed to be either a brown dwarf or a star with minimum mass around 40 Jupiter masses.[8] In 2022, Beta Caeli was imaged with the Gemini Planet Imager, with a point source that very likely is β Caeli B being detected.[6] This object may be the source of the X-ray emission coming from the same location, which suggests the companion could be a late-type star.[8]
The existence of additional companions beyond 55 astronomical units is ruled out.[8]
References
- ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 1.11 1.12 1.13 1.14 1.15 1.16 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Cousins, A. W. J. (1973), "UBV photometry of some southern stars", Monthly Notes of the Astronomical Society of Southern Africa 32: 11, Bibcode: 1973MNSSA..32...11C.
- ↑ 3.0 3.1 3.2 3.3 Gray, R. O. et al. (July 2006), "Contributions to the Nearby Stars (NStars) Project: spectroscopy of stars earlier than M0 within 40 pc-The Southern Sample", The Astronomical Journal 132 (1): 161–170, doi:10.1086/504637, Bibcode: 2006AJ....132..161G.
- ↑ 4.0 4.1 Torres, C. A. O. et al. (December 2006), "Search for associations containing young stars (SACY). I. Sample and searching method", Astronomy and Astrophysics 460 (3): 695–708, doi:10.1051/0004-6361:20065602, Bibcode: 2006A&A...460..695T.
- ↑ 5.0 5.1 5.2 Ammler-von Eiff, Matthias; Reiners, Ansgar (June 2012), "New measurements of rotation and differential rotation in A-F stars: are there two populations of differentially rotating stars?", Astronomy & Astrophysics 542: A116, doi:10.1051/0004-6361/201118724, Bibcode: 2012A&A...542A.116A.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 6.6 6.7 García, Luciano H. et al. (August 17, 2022), "High-contrast imaging of HD 29992 and HD 196385 with the Gemini Planet Imager" (in en), Monthly Notices of the Royal Astronomical Society 515 (4): 4999–5008, doi:10.1093/mnras/stac1929, ISSN 0035-8711.
- ↑ "bet Cae". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=bet+Cae.
- ↑ 8.0 8.1 8.2 8.3 Borgniet, Simon et al. (2017), "Extrasolar planets and brown dwarfs around AF-type stars. IX. The HARPS southern sample", Astronomy & Astrophysics 599: A57, doi:10.1051/0004-6361/201628805, Bibcode: 2017A&A...599A..57B.
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