Astronomy:HD 42618
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| Constellation | Orion |
| Right ascension | 06h 12m 00.567s[1] |
| Declination | +06° 46′ 59.06″[1] |
| Apparent magnitude (V) | 6.85[2] |
| Characteristics | |
| Evolutionary stage | Main sequence |
| Spectral type | G4V[3] |
| B−V color index | 0.642±0.007[2] |
| Astrometry | |
| Radial velocity (Rv) | −53.52±0.14[4] km/s |
| Proper motion (μ) | RA: 197.247[1] mas/yr Dec.: −254.867[1] mas/yr |
| Parallax (π) | 40.9764 ± 0.0240[1] mas |
| Distance | 79.60 ± 0.05 ly (24.40 ± 0.01 pc) |
| Absolute magnitude (MV) | 5.03±0.06[3] |
| Details | |
| Mass | 0.92±0.02[5] M☉ |
| Radius | 0.94[5] R☉ |
| Luminosity | 0.918±0.012[5] L☉ |
| Surface gravity (log g) | 4.44±0.01[6] cgs |
| Temperature | 5,758±5 K[6] 5,765±17[5] K |
| Metallicity [Fe/H] | −0.096±0.005 dex[6] −0.10±0.02[5] dex |
| Rotation | 16.9 d[7] |
| Rotational velocity (v sin i) | 1.83±0.11[6] km/s |
| Age | 5.51±0.71 Gyr[6] 5.5±0.2[5] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
HD 42618 is a well-studied[7] star with an exoplanetary companion in the equatorial constellation of Orion. With an apparent visual magnitude of 6.85[2] it is too faint to be readily visible to the naked eye. This system is located at a distance of 79.6 light years from the Sun based on parallax measurements. It has a relatively high proper motion, traversing the celestial sphere at an angular rate of 0.321″ per year.[9] HD 42618 is drifting closer with a radial velocity of −53.5[4] km/s and is predicted to come as near as 42.6 light-years in around 297,000 years.[2]
The stellar classification of HD 42618 is G4V,[3] which shows it to be an ordinary G-type main-sequence star. It is considered a close solar analog, which means the physical properties of the star are particularly similar to those of the Sun.[10] Seismic model indicates the star is older and more evolved than the Sun with an age of about 5.5 billion years.[5] It is spinning with a low projected rotational velocity of 1.8 km/s,[6] with the rotation rate being consistent with the star's low activity level.[11] The star has 92% of the mass of the Sun and 94% of the Sun's radius. The surface metallicity is lower than in the Sun,[5] with the abundance patterns being consistent with a solar-type star.[11] HD 42618 is radiating 92% of the luminosity of the Sun from its photosphere at an effective temperature of 5,765 K.[5]
In 2016, the discovery of a candidate exoplanet companion orbiting HD 42618 was announced. Designated HD 42618 b, it was found using the radial velocity method which showed a periodicity of 149.6 days. The orbital elements have the planet orbiting at a distance of 0.55 astronomical unit|AU from the host star with an orbital eccentricity (ovalness) of 0.2 and a Neptune-like mass. A second signal with a period of 388 days was detected, but this is unconfirmed and may be false. A 4,850 day signal is likely the result of star's magnetic activity cycle.[7]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | ≥ 14.4+2.5 −2.4 M⊕ |
0.554±0.011 | 149.61+0.37−0.34 | 0.19+0.15−0.12 | — | — |
References
- ↑ 1.0 1.1 1.2 1.3 Brown, A. G. A. (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics 649: A1. doi:10.1051/0004-6361/202039657. Bibcode: 2021A&A...649A...1G. Gaia EDR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 3.2 Medhi, B. J. et al. (July 2007), "Results from a spectroscopic survey in the CoRoT fields. I. Search for chromospherically active stars", Astronomy and Astrophysics 469 (2): 713–719, doi:10.1051/0004-6361:20054173, Bibcode: 2007A&A...469..713M.
- ↑ 4.0 4.1 Brown, A. G. A. (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics 616: A1. doi:10.1051/0004-6361/201833051. Bibcode: 2018A&A...616A...1G. Gaia DR2 record for this source at VizieR.
- ↑ 5.0 5.1 5.2 5.3 5.4 5.5 5.6 5.7 5.8 Castro, M. et al. (August 2021), "Modeling of two CoRoT solar analogues constrained by seismic and spectroscopic analysis", Monthly Notices of the Royal Astronomical Society 505 (2): 2151–2158, doi:10.1093/mnras/stab1410, Bibcode: 2021MNRAS.505.2151C.
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 dos Santos, Leonardo A. et al. (August 2016), "The Solar Twin Planet Search. IV. The Sun as a typical rotator and evidence for a new rotational braking law for Sun-like stars", Astronomy & Astrophysics 592: 8, doi:10.1051/0004-6361/201628558, A156, Bibcode: 2016A&A...592A.156D.
- ↑ 7.0 7.1 7.2 7.3 Fulton, Benjamin J. et al. (October 2016), "Three Temperate Neptunes Orbiting Nearby Stars", The Astrophysical Journal 830 (1): 19, doi:10.3847/0004-637X/830/1/46, 46, Bibcode: 2016ApJ...830...46F.
- ↑ "HD 42618". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+42618.
- ↑ Lépine, Sébastien; Shara, Michael M. (March 2005), "A Catalog of Northern Stars with Annual Proper Motions Larger than 0.15" (LSPM-NORTH Catalog)", The Astronomical Journal 129 (3): 1483–1522, doi:10.1086/427854, Bibcode: 2005AJ....129.1483L.
- ↑ Soubiran, C.; Triaud, A. (May 2004), "The Top Ten solar analogs in the ELODIE library", Astronomy and Astrophysics 418 (3): 1089–1100, doi:10.1051/0004-6361:20035708, Bibcode: 2004A&A...418.1089S.
- ↑ 11.0 11.1 Morel, T. et al. (April 2013), "Abundance study of the two solar-analogue CoRoT targets HD 42618 and HD 43587 from HARPS spectroscopy", Astronomy & Astrophysics 552: 10, doi:10.1051/0004-6361/201220883, A42, Bibcode: 2013A&A...552A..42M.
Further reading
- Castro, M.; Baudin, F.; Marques, J.; do Nascimento Jr., J. D. (2018), "The impact of GAIA astrometry on the evolutionary status of the seismic analog HD 42618", Boletim da Sociedade Astronômica Brasileira 30 (1): 93–94, https://sab-astro.org.br/wp-content/uploads/2018/10/MatthieuCastr.pdf, retrieved 2022-02-17.
- Barban, C. et al. (June 2013), "Solar-like oscillations in distant stars as seen by CoRoT : the special case of HD 42618, a solar sister", Journal of Physics: Conference Series 440 (1): 012030, doi:10.1088/1742-6596/440/1/012030, 012030, Bibcode: 2013JPhCS.440a2030B.
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