41 Sextantis
Spectroscopic binary with an Am star
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41 Sextantis (HD 93903; HR 4237; 74 G. Sextantis), or simply 41 Sex is a spectroscopic binary located in the equatorial constellation Sextans. It has an apparent magnitude of 5.79,[2] making it faintly visible to the naked eye under ideal conditions. The system is located relatively close at a distance of 310 light-years based on Gaia DR3 parallax measurements[1] and it is drifting closer with a heliocentric radial velocity of approximately −4.9 km/s.[6] At its current distance, 41 Sex's brightness is diminished by an interstellar extinction of 0.16 magnitudes[17] and it has an absolute magnitude of +0.91.[7]
 | |
| Observation data Epoch J2000.0 Equinox ICRS | |
|---|---|
| Constellation | Sextans |
| Right ascension | 10h 50m 18.05639s[1] |
| Declination | −08° 53′ 51.9538″[1] |
| Apparent magnitude (V) | 5.79±0.01[2] |
| Characteristics | |
| Aa | |
| Spectral type | kA3 hA7V mA9[3] |
| U−B color index | +0.13[4] |
| B−V color index | +0.16[4] |
| Ab | |
| Spectral type | F/G[5] |
| Astrometry | |
| Radial velocity (Rv) | −4.9±2.9[6] km/s |
| Proper motion (μ) | RA: −5.694 mas/yr[1] Dec.: −15.814 mas/yr[1] |
| Parallax (π) | 10.5160±0.0428 mas[1] |
| Distance | 310 ± 1 ly (95.1 ± 0.4 pc) |
| Absolute magnitude (MV) | +0.91[7] |
| Orbit[5] | |
| Primary | Aa |
| Period (P) | 6.1670 d |
| Eccentricity (e) | 0.014±0.006[8] |
| Periastron epoch (T) | 2,453,690.7442±0.0011 JD |
| Argument of periastron (ω) (secondary) | 272±4[8]° |
| Semi-amplitude (K1) (primary) | 46.67±0.04 km/s |
| Semi-amplitude (K2) (secondary) | 93.06±0.20 km/s |
| Details | |
| Aa | |
| Mass | 2.23[9] M☉ |
| Radius | 3.10±0.16[10] R☉ |
| Luminosity | 32.6±1.7[11] L☉ |
| Surface gravity (log g) | 3.83+0.10 −0.07[12] cgs |
| Temperature | 7,759[13] K |
| Metallicity [Fe/H] | −0.23[14] dex |
| Rotational velocity (v sin i) | 24[5] km/s |
| Age | 698+128 −108[13] Myr |
| Ab | |
| Mass | 1.05[9] M☉ |
| Radius | 1.3±0.2[5] R☉ |
| Luminosity | 1.8±0.5[5] L☉ |
| Rotational velocity (v sin i) | 10[5] km/s |
| Other designations | |
| 41 Sex, 74 G. Sextantis[15], BD−08°3018, FK5 1281, GC 14906, HD 93903, HIP 52980, HR 4237, SAO 137823, CCDM J10503-0853A, WDS J10503-0854A[16] | |
| Database references | |
| SIMBAD | data |
The visible component has a stellar classification of kA3hA7VmA9,[3] indicating that it is an Am star with the calcium K-lines of an A3 star, the hydrogen lines and effective temperature of an A7 main-sequence star, and the metal lines of an A9 star. Houk & Swift (1999) give a class of A2/3 III,[18] indicating that it is an A-type star that has the characteristics of an A2 and A3 giant star. It has 2.23 times the mass of the Sun[9] and a slightly enlarged radius 3.10 times that of the Sun.[10] It radiates 32.6 times the luminosity of the Sun[11] from its photosphere at an effective temperature of 7,759 K,[13] giving it a white-hue when viewed in the night sky. 41 Sextantis Aa is metal-deficient with an iron abundance 58.9% that of the Sun[14] and it spins modestly with a projected rotational velocity of 24 km/s.[5]
The companion's spectrum is very weak compared to the primary, but it is said to be either a late F-type star or an early G-type star.[5] It has 105% the mass of the Sun[9] and 1.3 times the radius of the Sun.[5] It radiates 1.8 times the luminosity of the Sun from its photosphere.[5] It spins slowly with a projected rotational velocity of 10 km/s.[5]