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Table 1

Stellar parameters for Sigma Ori AB (also known as 48 Ori, HD 37468, and HIP 26549) and calculated space velocity parameters.

RA (J2000) 05:38:44.768 Caballero (2007)
Dec (J2000) –02:36:00.25
Spectral type O9.5V + B0.5 V Hoffleit & Jaschek (1982)
L (log(L/L)) 4.78 Lee (1968)
log Q0 (s-1) 47.88 Martins et al. (2005a)
μα (mas yr-1) 4.61 ± 0.88 Perryman et al. (1997) a
μδ (mas yr-1) –0.4 ± 0.53 Perryman et al. (1997)
μα (km s-1) 6.8
μδ (km s-1) 5.7
vrad(LSR) (km s-1) 11.45 Caballero (2008)
d (pc) 334 Caballero (2008)
   (M yr-1) 8.0 × 10-8 Howarth & Prinja (1989)
2.0 × 10-10 Najarro et al. (2011)
v (km s-1) 1060 Howarth & Prinja (1989)
1500 Najarro et al. (2011)

θ (°) 49.9 This work
i (°) 49.4
v (km s-1) 15.1

Notes. L is the luminosity of the star; Q0 is the ionizing photon flux; vrad is the radial velocity; μα and μδ are the proper motions in RA and Dec, respectively; d is the measured distance; is the mass-loss rate. The proper motion position angle θ is measured from north to east; i is the inclination angle with respect to the sky and v is the total space velocity of σ Ori AB.


Values for proper motion published in van Leeuwen (2007) show a large discrepancy between different members σ Ori central cluster. Therefore, we adopt proper motion parameters from Perryman et al. (1997). In this case, proper motions between σ Ori AB are similar to the values for σ Ori D and σ Ori E listed in Caballero (2007).

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