Astronomy:HD 43317
| Observation data Equinox J2000.0]] (ICRS) | |
|---|---|
| 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−B color index | −0.646[2] |
| B−V color 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: −4.231[1] mas/yr Dec.: −3.765[1] mas/yr |
| Parallax (π) | 3.0975 ± 0.0517[1] mas |
| 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 | |
| Database references | |
| SIMBAD | data |
HD 43317 is a variable star in the equatorial constellation of Orion, the hunter. It has an apparent visual magnitude of 6.63,[2] which is faint enough to be a challenge to view with the naked eye under good conditions. Based on parallax measurements, it is located at a distance of approximately 1,050 light years from the Sun. It is drifting further away with a heliocentric radial velocity of about 13 km/s.[6] This star is a member of an open cluster designated OCSN 63.[9]
Observations
During 2009–2010, HD 43317 was observed by the CoRoT space telescope during the LRa03 (long run) sequence for asteroseismological purposes. This program lasted for a period of 150.41 days, during which the star was under almost constant observation. After being combined with HARPS data, the star was classified as a hybrid slowly pulsating B-type star and a Beta Cephei variable. Both g (gravity) and p (pressure) mode pulsations were detected. It is spinning rapidly at about half of its critical velocity.[10]
The photometry and spectrometry of HD 43317 showed rotational modulation of regions with temperature or chemical differences. These are an indirect indicator of a magnetic field. In addition, X-ray emission was detected by ROSAT, which also suggests a potential magnetic field. A magnetic field was directly detected with the Téléscope Bernard Lyot during 2012. The longitudinal field strength was found to vary with the 21.5 h rotation period, ranging from −140 G to 180 G.[11] Modelling of the star's dipolar field found a strength between 1 and 1.5 kG. This is strong enough to force uniform rotation in the outer radiative zone of the star.[5]
The CoRoT light 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 the core, the central mass fraction of hydrogen is 54%, compared to 70% for a newly formed main sequence star and 0.1% at the end of main sequence lifetime. Spectroscopic analysis shows an effective temperature of around 17,350 in the stellar atmosphere. A refined estimate of the surface magnetic field strength found a value of 1,312±332 G.[13] The magnetic field near the core has a seismically modelled strength of 5×105 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]
References
- ↑ 1.0 1.1 1.2 1.3 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 2.6 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters 38 (5): 331, doi:10.1134/S1063773712050015, Bibcode: 2012AstL...38..331A.
- ↑ 3.0 3.1 3.2 3.3 3.4 3.5 3.6 3.7 Lecoanet, Daniel et al. (May 2022), "Asteroseismic inference of the near-core magnetic field strength in the main-sequence B star HD 43317", Monthly Notices of the Royal Astronomical Society: Letters 512 (1): L16–L20, doi:10.1093/mnrasl/slac013, Bibcode: 2022MNRAS.512L..16L.
- ↑ Lesh, Janet Rountree (December 1968), "The Kinematics of the Gould Belt: an Expanding Group?", Astrophysical Journal Supplement 17: 371, doi:10.1086/190179, Bibcode: 1968ApJS...17..371L.
- ↑ 5.0 5.1 Buysschaert, B. et al. (September 2017), "Magnetic characterization of the SPB/β Cep hybrid pulsator HD 43317", Astronomy & Astrophysics 605: id. A104, doi:10.1051/0004-6361/201731012, Bibcode: 2017A&A...605A.104B.
- ↑ 6.0 6.1 Gontcharov, G. A. (2006), "Pulkovo compilation of radial velocities for 35495 stars in a common system", Astronomy Letters 32 (11): 759–771, doi:10.1134/S1063773706110065, Bibcode: 2006AstL...32..759G.
- ↑ 7.0 7.1 7.2 7.3 Prat, V. et al. (April 2020), "Period spacings of gravity modes in rapidly rotating magnetic stars. II. The case of an oblique dipolar fossil magnetic field", Astronomy & Astrophysics 636: id. A100, doi:10.1051/0004-6361/201937398, Bibcode: 2020A&A...636A.100P.
- ↑ "HD 43317". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+43317.
- ↑ Qin, Songmei et al. (March 2023), "Hunting for Neighboring Open Clusters with Gaia DR3: 101 New Open Clusters within 500 pc", The Astrophysical Journal Supplement Series 265 (1): id. 12, doi:10.3847/1538-4365/acadd6, Bibcode: 2023ApJS..265...12Q.
- ↑ Pápics, P. I. et al. (June 2012), "Gravito-inertial and pressure modes detected in the B3 IV CoRoT target HD 43317", Astronomy & Astrophysics 542: id. A55, doi:10.1051/0004-6361/201218809, Bibcode: 2012A&A...542A..55P.
- ↑ Briquet, M. et al. (September 2013), "Discovery of a magnetic field in the CoRoT hybrid B-type pulsator HD 43317", Astronomy & Astrophysics 557: id. L16, doi:10.1051/0004-6361/201321779, Bibcode: 2013A&A...557L..16B.
- ↑ "IAS CoRoT Public Archive". IAS/IDOC. http://idoc-corot.ias.u-psud.fr/sitools/client-user/COROT_N2_PUBLIC_DATA/project-index.html#.
- ↑ Buysschaert, B. et al. (August 2018), "Forward seismic modeling of the pulsating magnetic B-type star HD 43317", Astronomy & Astrophysics 616: id. A148, doi:10.1051/0004-6361/201832642, Bibcode: 2018A&A...616A.148B.
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