HD 149382

HD 149382
Observation data
Epoch J2000      Equinox J2000
Constellation Ophiuchus
Right ascension 16h 34m 23.33337s[1]
Declination −04° 00′ 52.0301″[1]
Apparent magnitude (V) 8.943[2]
Characteristics
Spectral type B5 VI[3]
U−B color index −1.143[2]
B−V color index −0.282[2]
V−R color index −0.127[2]
R−I color index −0.135[2]
Astrometry
Radial velocity (Rv)+3[4] km/s
Proper motion (μ) RA: −6.234[1] mas/yr
Dec.: −5.780[1] mas/yr
Parallax (π)13.2407 ± 0.0567 mas[1]
Distance246 ± 1 ly
(75.5 ± 0.3 pc)
Details
Mass0.29 – 0.53[5] M☉
Radius0.143[6] R☉
Luminosity25.2[6] L☉
Surface gravity (log g)5.80±0.05[5] cgs
Temperature35,500±500[5] K
Metallicity [Fe/H]−1.30[3] dex
Rotational velocity (v sin i)4.9±1.4[5] km/s
Other designations
BD−03°3967, HD 149382, HIP 81145, SAO 141250[7]
Database references
SIMBADdata

HD 149382 is a hot subdwarf star in the constellation of Ophiuchus with an apparent visual magnitude of 8.943.[2] This is too faint to be seen with the naked eye even under ideal conditions, although it can be viewed with a small telescope.[8] Based upon parallax measurements, this star is located at a distance of about 246 light-years (75.5 parsecs) from the Earth.

This is the brightest known B-type subdwarf star with a stellar classification of B5 VI. It is generating energy through the thermonuclear fusion of helium at its core (triple-alpha process).[3] The effective temperature of the star's outer envelope is about 35,500 K, giving it the characteristic blue-white hue of a B-type star. Although only about one seventh the diameter of the Sun, it radiates about 25 times as much due to its high temperature. HD 149382 has a visual companion located at an angular separation of 1 arcsecond.[9]

In 2009, a substellar companion, perhaps even a superjovian planet, was announced orbiting the star.[5] This candidate object was estimated to have nearly half the mass of the Sun. In 2011, this discovery was thrown into doubt when an independent team of astronomers were unable to confirm the detection. Their observations rule out a companion with a mass greater than Jupiter orbiting with a period of less than 28 days.[9]

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  2. ^ a b c d e f Cite error: The named reference aj137_5 was invoked but never defined (see the help page).
  3. ^ a b c Cite error: The named reference mnras374_2_664 was invoked but never defined (see the help page).
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  5. ^ a b c d e Cite error: The named reference apjl702_1_L96 was invoked but never defined (see the help page).
  6. ^ a b Cite error: The named reference ticv8 was invoked but never defined (see the help page).
  7. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference sherrod_koed2003 was invoked but never defined (see the help page).
  9. ^ a b Cite error: The named reference apj743_1_88 was invoked but never defined (see the help page).