HD 2638
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Cetus |
| Right ascension | Template:RA[1] |
| Declination | Template:DEC[1] |
| Apparent magnitude (V) | 9.44[2] |
| Characteristics | |
| Spectral type | K1V[3] (G8V + M1V)[4] |
| B−V Template:Engvar | Script error: No such module "val".[2] |
| Astrometry | |
| Radial velocity (Rv) | Script error: No such module "val".[1] km/s |
| Proper motion (μ) | RA: Script error: No such module "val".[1] mas/yr Dec.: Script error: No such module "val".[1] mas/yr |
| Parallax (π) | 18.1656±0.0510 mas[1] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | 5.96[2] |
| Orbit[5] | |
| Primary | HD 2638 A |
| Companion | HD 2638 BC |
| Period (P) | 130 yr |
| Semi-major axis (a) | 25.5±1.9 AU |
| Details[6] | |
| A | |
| Mass | Script error: No such module "val". Template:Solar mass |
| Radius | Script error: No such module "val". Template:Solar radius |
| Luminosity | Script error: No such module "val". Template:Solar luminosity |
| Surface gravity (log g) | Script error: No such module "val". cgs |
| Temperature | Script error: No such module "val". K |
| Metallicity [Fe/H] | Script error: No such module "val".[7] dex |
| Age | Script error: No such module "val". Gyr |
| BC | |
| Mass | Script error: No such module "val".[4] Template:Solar mass |
| Radius | Script error: No such module "val".[4] Template:Solar radius |
| Luminosity | Script error: No such module "val".[4] Template:Solar luminosity |
| Surface gravity (log g) | Script error: No such module "val".[4] cgs |
| Temperature | Script error: No such module "val".[4] K |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| Template:Odlist[8] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
Script error: No such module "Check for unknown parameters".
HD 2638 is a ternary star system[9] system in the equatorial constellation of Cetus. The pair have an angular separation of Script error: No such module "val". along a position angle of 166.7°, as of 2015.[9] This is system too faint to be visible to the naked eye, having a combined apparent visual magnitude of 9.44;[2] a small telescope is required. The distance to this system is 179.5 light years based on parallax, and it is drifting further away with a radial velocity of +9.6 km/s.[1] The magnitude 7.76 star HD 2567 forms a common proper motion companion to this pair[9] at projected separation 839″.[5]
The HD 2638 members A and BC have a projected separation of about Script error: No such module "val". and thus an orbital period of around 130 years.[4] They have a combined stellar classification of K1V.[3] The primary component is a G-type main-sequence star with a class of G8V.[4] It is smaller and less massive than the Sun, and has a lower luminosity.[6] The secondary is a binary consisting of two red dwarf stars on close orbit with combined mass less than half the mass of the primary, and a composite spectral class of M1V.[4]
Planetary system
In 2005, the discovery of an extrasolar planet HD 2638 b orbiting the primary was announced by the Geneva Extrasolar Planet Search Team. The planet has a mass 0.48 times that of Jupiter and 152.6 times that of Earth.[10] The planet existence was placed under doubt in 2015 due to discovered additional stellar companions.[5]
Template:OrbitboxPlanet begin Template:OrbitboxPlanet
|}Script error: No such module "Check for unknown parameters".
See also
References
<templatestyles src="Reflist/styles.css" />
- ↑ a b c d e f g Template:Cite Gaia DR2
- ↑ a b c d Script error: No such module "Citation/CS1".
- ↑ a b Script error: No such module "Citation/CS1".
- ↑ a b c d e f g h i Script error: No such module "Citation/CS1".
- ↑ a b c Script error: No such module "citation/CS1".
- ↑ a b Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
- ↑ Template:Cite simbad
- ↑ a b c Script error: No such module "Citation/CS1".
- ↑ Script error: No such module "Citation/CS1".
Script error: No such module "Check for unknown parameters".