HD 159176

HD 159176

A light curve for V1036 Scorpii, plotted from TESS data.[1] The orbital period is marked in red.
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Scorpius
Right ascension 17h 34m 42.49213s[2]
Declination −32° 34′ 53.9955″[2]
Apparent magnitude (V) 5.71 - 5.79[3]
Characteristics
Spectral type O6.5V + O7V[4]
Variable type Rotating ellipsoidal[3]
Astrometry
Proper motion (μ) RA: 2.621±0.083[2] mas/yr
Dec.: −0.798±0.058[2] mas/yr
Parallax (π)1.1666 ± 0.0707 mas[2]
Distance2,800 ± 200 ly
(860 ± 50 pc)
Orbit[5]
PrimaryPrimary
CompanionSecondary
Period (P)3.366767 d
Eccentricity (e)0.0
Periastron epoch (T)2448885.420±0.003
Semi-amplitude (K1)
(primary)		215.7±1.4 km/s
Semi-amplitude (K2)
(secondary)		218.1±1.5 km/s
Details
Primary
Mass46.4+14.3
−9.5[4] M☉
Luminosity5.50±0.10[4] L☉
Temperature38,000[4] K
Secondary
Mass44.2+13.6
−9.1[4] M☉
Luminosity5.41±0.10[4] L☉
Temperature36,750[4] K
Other designations
V1036 Scorpii, HIP 86011, HR 6535, SAO 208977, Boss 4444[6]
Database references
SIMBADdata

HD 159176, also known as Boss 4444 and V1036 Scorpii, is a variable star about 2,800 light years from the Earth, in the constellation Scorpius.[2] It is a 5th magnitude star, so it should be visible to the naked eye of an observer far from city lights. HD 159176 is the brightest star in the young open cluster NGC 6383.[4] It is a binary star composed of two nearly identical O stars in a circular orbit.[7]

In 1930, Robert Trumpler discovered that HD 159176 is a spectroscopic binary. He noted that the two stars have very nearly the same brightness and spectral type. In addition, he was observing at the Lick Observatory, so the far southern declination of the star meant it could only be observed near transit. Those three things together prevented him from unambiguously measuring the orbital period.[8] The first full set of orbital elements, including the 3.3664±0.0003 day period, was derived by Peter Conti et al. in 1975.[9] Also in 1975, photometric observations by J. C. Thomas showed that HD 159176 is a rotating ellipsoidal variable.[10][11] The star's spectra exhibit the Struve–Sahade effect.[4] HD 159176 was given the variable star designation V1036 Scorpii, in 1997.[12]

Although HD 159176 was long considered to be a non-eclipsing binary,[4][7][13][14] data from the Transiting Exoplanet Survey Satellite does show eclipses.[15]

HD 159176 has an X-ray luminosity far higher than would be expected from two isolated O stars. The excess X-rays may arise from interacting stellar winds.[7]

  1. ^ Cite error: The named reference MAST was invoked but never defined (see the help page).
  2. ^ a b c d e f Cite error: The named reference dr3 was invoked but never defined (see the help page).
  3. ^ a b Cite error: The named reference gcvs was invoked but never defined (see the help page).
  4. ^ a b c d e f g h i j Cite error: The named reference Penny2016 was invoked but never defined (see the help page).
  5. ^ Cite error: The named reference Stickland1993 was invoked but never defined (see the help page).
  6. ^ Cite error: The named reference SIMBAD was invoked but never defined (see the help page).
  7. ^ a b c Cite error: The named reference DeBecker2004 was invoked but never defined (see the help page).
  8. ^ Cite error: The named reference Trumpler1930 was invoked but never defined (see the help page).
  9. ^ Cite error: The named reference Conti1975 was invoked but never defined (see the help page).
  10. ^ Cite error: The named reference Thomas1975 was invoked but never defined (see the help page).
  11. ^ Cite error: The named reference Thomas1994 was invoked but never defined (see the help page).
  12. ^ Cite error: The named reference Kazarovets1997 was invoked but never defined (see the help page).
  13. ^ Cite error: The named reference Pfeiffer1997 was invoked but never defined (see the help page).
  14. ^ Cite error: The named reference IVSI was invoked but never defined (see the help page).
  15. ^ Cite error: The named reference Burssens2020 was invoked but never defined (see the help page).