HD 93403

HD 93403 is a spectroscopic binary containing two highly luminous hot blue stars. It is 10,000 light years away in the Carina Nebula in the constellation Carina. It appears to have spectral type O5.5III, but this is composed of two spectra from a blue supergiant and blue main sequence star of spectral type O5.5I and O7V respectively. The two stars orbit every 15 days with a separation that varies from 93 R_☉ to 149 R_☉. The binary is shedding mass at the high rate of 0.0005 M_☉ per year.^[3]

HD 93403

Observation data Epoch J2000      Equinox J2000
Constellation	Carina
Right ascension	10h 45m 44.11931s[1]
Declination	−59° 24′ 28.1431″[1]
Apparent magnitude (V)	7.272[2]
Characteristics
Spectral type	O5.5III(fc)var[3] (O5.5I + O7V[4])
U−B color index	−0.747[2]
B−V color index	+0.212[2]
Astrometry
Radial velocity (Rv)	14.80 km/s
Proper motion (μ)	RA: -7.27 mas/yr Dec.: 2.45 mas/yr
Parallax (π)	1.22 ± 0.45 mas[1]
Distance	3,200[4] pc
Orbit[5]
Period (P)	15.093 days
Semi-major axis (a)	121 R☉
Eccentricity (e)	0.234
Inclination (i)	~31°
Semi-amplitude (K1) (primary)	79.3 km/s
Semi-amplitude (K2) (secondary)	139.0 km/s
Details[4]
Primary
Mass	68.5[5] M☉
Radius	24 R☉
Luminosity	1,050,000 L☉
Temperature	39,300 K
Secondary
Mass	37.3[5] M☉
Radius	10 R☉
Luminosity	257,000 L☉
Temperature	40,100 K
Other designations
HD 93403, HIP 52628, CD−58°3545, 2MASS J10454411-5924281, GSC 08626-00641, TYC 8626-641-1
Database references
SIMBAD	data

HD 93403 exhibits the Struve-Sahade effect, where the strength of the spectral lines of the individual components varies during the orbit. It also has colliding stellar winds that produce variable x-ray^[6] and non-thermal radio emission.^[7]

See also

• List of most massive stars

References

1. van Leeuwen, Floor (13 August 2007). "Validation of the new Hipparcos reduction". Astronomy & Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. eISSN 1432-0746. ISSN 0004-6361.
2. Maíz-Apellániz, Jesús; Walborn, Nolan R.; Galué, Héctor Á.; Wei, Lisa H. (2004). "A Galactic O Star Catalog". The Astrophysical Journal Supplement Series. 151 (1): 103–148. arXiv:astro-ph/0311196. Bibcode:2004ApJS..151..103M. doi:10.1086/381380. S2CID 118813863.
3. Sota, A.; Maíz Apellániz, J.; Morrell, N. I.; Barbá, R. H.; Walborn, N. R.; Gamen, R. C.; Arias, J. I.; Alfaro, E. J. (2014). "The Galactic O-Star Spectroscopic Survey (GOSSS). II. Bright Southern Stars". The Astrophysical Journal Supplement Series. 211 (1): 84. arXiv:1312.6222. Bibcode:2014ApJS..211...10S. doi:10.1088/0067-0049/211/1/10. S2CID 118847528. 10.
4. Rauw, G.; Vreux, J.-M.; Stevens, I. R.; Gosset, E.; Sana, H.; Jamar, C.; Mason, K. O. (2002). "Phase-resolved X-ray and optical spectroscopy of the massive binary HD 93403". Astronomy and Astrophysics. 388 (2): 552. Bibcode:2002A&A...388..552R. doi:10.1051/0004-6361:20020523.
5. Rauw, G.; Sana, H.; Gosset, E.; Vreux, J.-M.; Jehin, E.; Parmentier, G. (2000). "A new orbital solution for the massive binary system HD 93403". Astronomy and Astrophysics. 360: 1003. Bibcode:2000A&A...360.1003R.
6. Analysis of the X-ray emission of OB stars: O stars
7. Palate, M.; Rauw, G.; Koenigsberger, G.; Moreno, E. (2013). "Spectral modelling of massive binary systems". Astronomy & Astrophysics. 552: A39. arXiv:1302.5201. Bibcode:2013A&A...552A..39P. doi:10.1051/0004-6361/201219754. S2CID 54771449.