N Scorpii, also known as HD 148703, is a solitary,[14] bluish-white hued star located in the southern constellation Scorpius. It has an apparent magnitude of 4.23, making it readily visible to the naked eye. N Scorpii was initially given the Bayer designation Alpha Normae by Lacaille but it was later moved from Norma to Scorpius.[15] N Scorpii is currently located 550 light years away based on parallax measurements from the Hipparcos satellite and is part of the Upper Scorpius–Centaurus region of the Scorpius–Centaurus association.[16]
Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
---|---|
Constellation | Scorpius |
Right ascension | 16h 31m 22.93300s[1] |
Declination | −34° 42′ 15.7146″[1] |
Apparent magnitude (V) | 4.23[2] |
Characteristics | |
Spectral type | B2 III-IV[3] |
U−B color index | −0.76[2] |
B−V color index | −0.17[2] |
Variable type | candidate β Cephei[4] |
Astrometry | |
Radial velocity (Rv) | 0.8±1.5[5] km/s |
Proper motion (μ) | RA: −12.05±0.20 mas/yr[1] Dec.: −18.16±0.13 mas/yr[1] |
Parallax (π) | 5.88 ± 0.19 mas[1] |
Distance | 550 ± 20 ly (170 ± 5 pc) |
Absolute magnitude (MV) | −1.91[6] |
Details | |
Mass | 7.8±0.1[7] M☉ |
Radius | 6.25[8] R☉ |
Luminosity (bolometric) | 6,918[9] L☉ |
Surface gravity (log g) | 4.0[9] cgs |
Temperature | 21,877[9] K |
Metallicity [Fe/H] | +0.01[10] dex |
Rotational velocity (v sin i) | 70±8[11] km/s |
Age | 22±4[7] Myr |
Other designations | |
Database references | |
SIMBAD | data |
N Scorpii has been given several stellar classifications over the years. It has been given the luminosity class of a main sequence star (V),[17] a subgiant (IV),[18] an evolved giant star (III),[19] or a blend between the last two classes (III-IV).[3] It is generally classified as either a B2 or B3 star several times hotter than the Sun. HD 148703 is a candidate β Cephei variable[4] and its variability was first noticed in 1983 by C. Sterken.[20] Further observations were made by Abt et al. (2002) by observing its projected rotational velocity.[21] It was identified as a candidate in 2002 in a survey for non-radial pulsations in B-type stars.[22]
The object has two generally accepted classes: B2 III-IV and B2 IV. It has 7.8 times the mass of the Sun[7] and 6.25 times its size.[8] It has a bolometric luminosity 6,918 times greater than the Sun from its photosphere at an effective temperature of 21,877 K.[9] N Scorpii is estimated to be 22 million years old,[7] which is twice the average age of the aforementioned association. Like most hot stars, N Scorpii spins rapidly, having a projected rotational velocity of 70 km/s.[11]