Alpha Mensae
Template:Location mark Location of α Mensae (circled) | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Mensa |
| Right ascension | Template:RA[1] |
| Declination | Template:DEC[1] |
| Apparent magnitude (V) | 5.09[2] |
| Characteristics | |
| Spectral type | G7 V[3] + M3.5-6.5 V[4] |
| U−B Template:Engvar | 0.33[5] |
| B−V Template:Engvar | 0.72[5] |
| Astrometry | |
| Radial velocity (Rv) | Script error: No such module "val".[1] km/s |
| Proper motion (μ) | RA: +121.596[1] mas/yr Dec.: −212.411[1] mas/yr |
| Parallax (π) | 97.9158±0.0573 mas[1] |
| Distance | Template:Rnd ± Template:Rnd ly (Template:Rnd ± Template:Rnd pc) |
| Absolute magnitude (MV) | 5.03[6] |
| Details[4] | |
| α Men 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". dex |
| Rotational velocity (v sin i) | Script error: No such module "val". km/s |
| Age | Script error: No such module "val". Gyr |
| α Men B | |
| Mass | Script error: No such module "val". Template:Solar mass |
| Radius | Script error: No such module "val". Template:Solar radius |
| Temperature | Script error: No such module "val". K |
| Metallicity [Fe/H] | {{{metal_fe2}}} dex |
| Other designations | |
| Template:Odlist[7] | |
| Database references | |
| SIMBAD | A |
| B | |
| Exoplanet Archive | data |
| ARICNS | data |
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α Mensae is the brightest star in the constellation Mensa. Its designation is Latinised as Alpha Mensae, while it has the proper name Hoerikwaggo.[8] At a magnitude of 5.09, it is the dimmest lucida (a constellation's brightest star) in the sky. Due to its declination, on Earth it is best visible from higher latitudes of the southern hemisphere, yet can also be seen, though low in the sky, from just north of the Equator when near its daily arc's highest point, the culmination. It is 33 light-years away from the Solar System. Alpha Mensae is a G-type main sequence star, forming a binary star system with a red dwarf companion.
Nomenclature
α Mensae (Latinised as Alpha Mensae, abbreviated to α Men or Alpha Men) is the star's Bayer designation. The IAU Working Group on Star Names approved the name Hoerikwaggo for this star on 12 December 2024 and it is now so entered in the IAU Catalog of Star Names. It is named after Table Mountain in South Africa, which the constellation Mensa represents; Hoerikwaggo is the Afrikaans form of the Khoekhoe name Huriǂoaxa.[8]
Properties
This star has a stellar classification of G7 V,[7] indicating that it is a G-type main sequence star that is generating energy by fusing hydrogen into helium at its core. It is of similar size but slightly cooler than the Sun, with 96.4% of the mass, 96% of the radius, and 81% of the Sun's luminosity.[4] The effective temperature of the stellar atmosphere is 5,569 K, and it has a slightly higher (129%) proportion of elements other than hydrogen and helium—what astronomers call the star's metallicity—compared to the Sun.[4] The estimated age of this star is 6.2 billion years, and is rotating at a relatively leisurely projected rotational velocity of 0.6 km/s.[4]
Located 33 light-years distant from the Sun, Alpha Mensae has a relatively high proper motion across the sky. It has already made its closest approach to the Sun, coming within about Script error: No such module "convert". around 250,000 years ago.[9] It has a red dwarf companion star at an angular separation of 3.05 arcseconds; equivalent to a projected separation of roughly 30 AU.[7][10][11] With a mass just 16.9% that of the Sun, the companion is fully convective.[4]
Search for planets
A candidate infrared excess was detected around this star, which would indicate the presence of a circumstellar disk at a radius of over 147 AU. The derived temperature of this dust is below 22 K.[12] However, data from Herschel Space Observatory failed to confirm this excess, leaving the finding in doubt.[13]
A 2023 study found evidence for a candidate planet around Alpha Mensae via Doppler spectroscopy. Its period is close to one Earth year, raising concerns that it might be an instrumental false positive; further observations are needed to confirm it.[14]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| (unconfirmed) | Script error: No such module "val". M🜨 | — | Script error: No such module "val". | Script error: No such module "val". | — | — |
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References
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- ↑ a b c d e f Template:Cite Gaia DR3
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- ↑ Script error: No such module "citation/CS1". (details on the stellar properties of the companion star)
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External links
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