| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Orion |
| Right ascension | 06h 15m 47.013s[1] |
| Declination | +04° 17′ 01.10″[1] |
| Apparent magnitude (V) | 6.63[2] |
| Characteristics | |
| Evolutionary stage | Main sequence[3] |
| Spectral type | B3.5 V[3] or B3 IV[4] |
| U−Bcolor index | −0.646[2] |
| B−Vcolor index | −0.164±0.010[2] |
| Variable type | SPB/β Cep hybrid[5] |
| Astrometry | |
| Radial velocity (Rv) | 13.0±4.4[6] km/s |
| Proper motion (μ) | RA: −4.231mas/yr[1] Dec.: −3.765mas/yr[1] |
| Parallax (π) | 3.0975±0.0517 mas[1] |
| Distance | 1,050 ± 20 ly (323 ± 5 pc) |
| Absolute magnitude (MV) | −1.13[2] |
| Details | |
| Mass | 5.8+0.1 −0.2[3] M☉ |
| Radius | 3.39[7] R☉ |
| Luminosity | 737.5[2] L☉ |
| Surface gravity (log g) | 4.0±0.1[3] cgs |
| Temperature | 17,350±750[3] K |
| Rotation | 0.897673(4) d[3] |
| Rotational velocity (v sin i) | 115±9[3] km/s |
| Age | 28.4[7] Myr |
| Other designations | |
| CoRoT 3412,BD+04° 1181,FK5 2478,HD 43317,HIP 29739,HR 2232,SAO 113653,PPM 150182[8] | |
| Database references | |
| SIMBAD | data |
HD 43317 is avariable star in theequatorialconstellation ofOrion, the hunter. It has anapparent visual magnitude of 6.63,[2] which is faint enough to be a challenge to view with thenaked eye under good conditions. Based onparallax measurements, it is located at a distance of approximately 1,050 light years from theSun. It is drifting further away with a heliocentricradial velocity of about 13 km/s.[6] This star is a member of anopen cluster designated OCSN 63.[9]
During 2009–2010, HD 43317 was observed by theCoRoT space telescope during theLRa03 (long run) sequence forasteroseismological purposes. This program lasted for a period of 150.41 days, during which the star was under almost constant observation. After being combined withHARPS data, the star was classified as a hybridslowly pulsating B-type star and aBeta Cephei variable. Bothg (gravity) andp (pressure) modepulsations were detected. It is spinning rapidly at about half of itscritical velocity.[10]
The photometry and spectrometry of HD 43317 showedrotational modulation of regions with temperature or chemical differences. These are an indirect indicator of amagnetic field. In addition,X-ray emission was detected byROSAT, which also suggests a potential magnetic field. A magnetic field was directly detected with theTéléscope Bernard Lyot during 2012. The longitudinal field strength was found to vary with the 21.5 hrotation period, ranging from−140 G to180 G.[11] Modelling of the star'sdipolar field found a strength between 1 and1.5 kG. This is strong enough to force uniform rotation in the outerradiative zone of the star.[5]
The CoRoTlight curve of the star displays 35 different frequencies, of which 28 are not related to the rotation period. Seismic modeling of the star determined a stellar mass equal to 5.8 times the mass of the Sun. At thecore, the central mass fraction of hydrogen is 54%, compared to 70% for a newly formedmain sequence star and 0.1% at the end of main sequence lifetime. Spectroscopic analysis shows aneffective temperature of around 17,350 in thestellar atmosphere. A refined estimate of the surface magnetic field strength found a value of1,312±332 G.[13] The magnetic field near the core has a seismically modelled strength of5×105 G. HD 43317 is the first main sequence star for which an interior magnetic field strength has been inferred.[3]
This star has an estimated radius of 3.39 times the girth of the Sun,[7] and is radiating 737.5[2] times the Sun's luminosity. It is about 28.4 million years old.[7]
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