N Scorpii

Location of N Scorpii on the map
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
N Scorpii, 72 G. Scorpii [12], CD−34°11044, CPD−34°6528, FK5 1431, GC 22195, HD 148703, HIP 80911, HR 6143, SAO 207732 [13]
Database references
SIMBAD	data

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]

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]

References