| Observation data EpochJ2000.0 EquinoxJ2000.0 (ICRS) | |
|---|---|
| Constellation | Eridanus |
| Right ascension | 04h 11m 51.93956s[2] |
| Declination | −06° 50′ 15.2864″[2] |
| Apparent magnitude (V) | 4.04[3] |
| Characteristics | |
| Spectral type | F0 III[4] |
| U−Bcolor index | +0.10[3] |
| B−Vcolor index | +0.32[3] |
| Variable type | δ Scuti[5] |
| Astrometry | |
| Proper motion (μ) | RA: +10.76[2]mas/yr Dec.: +81.92[2]mas/yr |
| Parallax (π) | 26.80±0.32 mas[2] |
| Distance | 122 ± 1 ly (37.3 ± 0.4 pc) |
| Absolute magnitude (MV) | +1.18[6] |
| Details | |
| Mass | 1.95[5] M☉ |
| Radius | 3.7±0.1[5] R☉ |
| Luminosity | 27[5] L☉ |
| Surface gravity (log g) | 3.39[4] cgs |
| Temperature | 6,963[4] K |
| Metallicity [Fe/H] | −0.01[4] dex |
| Rotational velocity (v sin i) | 108.1[7] km/s |
| Other designations | |
| Beid,ο1 Eri,38 Eri,BD−07°764,FK5 154,HD 26574,HIP 19587,HR 1298,SAO 131019[8] | |
| Database references | |
| SIMBAD | data |
Omicron1 Eridani (ο1 Eridani, abbreviatedOmicron1 Eri,ο1 Eri), also namedBeid/ˈbaɪd/,[9][10] is avariable star in theconstellation ofEridanus. With an averageapparent visual magnitude of 4.04,[3] it is visible to the naked eye on a clear, dark night. Based uponparallax measurements, it lies approximately 122 light-years from theSun.
ο1 Eridani (Latinised toOmicron1 Eridani) is the star'sBayer designation.
The system bears the traditional nameBeid derived from theArabic word بيضbayḍ meaning "eggs" (cf. neighboringKeid "(egg)shells"). In 2016, theInternational Astronomical Union organized aWorking Group on Star Names (WGSN)[11] to catalogue and standardize proper names for stars. The WGSN approved the nameBeid for this star on 12 September 2016 and it is now so included in the List of IAU-approved Star Names.[10]
InChinese,九州殊口 (Jiǔ Zhōu Shū Kǒu), meaningInterpreters of Nine Dialects, refers to anasterism consisting of ο1 Eridani,39 Eridani,Xi Eridani,Nu Eridani,56 Eridani and55 Eridani.[12] Consequently, theChinese name for Omicron1 Eridani itself is九州殊口二 (Jiǔ Zhōu Shū Kǒu èr, English:the Second Star of Interpreters of Nine Dialects).[13]
ο1 Eridani is anevolvedF-typegiant star with astellar classification of F0 III.[4] It is aDelta Scuti variable star that undergoes non-radial pulsations,[5] with a variation of just 0.03 magnitude over a period of 0.0747 days.[14] The star is spinning rapidly with aprojected rotational velocity of 108.1 km/s[7] and a rotation period of less than around 1.9 days.[5] This is creating an equatorial bulge that is 11% wider than the polar radius.[15] Omicron1 Eridani has nearly double themass of the Sun, 3.7 times theSun's radius, and shines with 27 times thesolar luminosity[5] from anouter atmosphere at aneffective temperature of 6,963 K.[4]
