HD 104237

HD 104237 is a candidate multiple star system[11] in the southern constellation of Chamaeleon. It has the variable star designation DX Chamaeleontis, abbreviated DX Cha; HD 104237 is the stellar designation from the Henry Draper Catalogue. The system is dimly visible to the naked eye with an apparent visual magnitude that ranges from 6.59 down to 6.70.[4] It is located at a distance of approximately 348 light-years from the Sun based on parallax measurements. The system is positioned just 2′ to the north-east[12] of the 5th magnitude star Epsilon Chamaeleontis,[13] and is a member of the ε Cha association of co-moving stars.[11]

HD 104237

A light curve for DX Chamaeleontis, plotted from Hipparcos data[1]
Observation data
Epoch J2000.0      Equinox J2000.0
Constellation Chamaeleon
Right ascension 12h 00m 05.087s[2]
Declination −78° 11′ 34.57″[2]
Apparent magnitude (V) 6.58[3] (6.59 to 6.70)[4]
Characteristics
Evolutionary stage Pre-main sequence
Spectral type A7.5Ve–A8Ve[5]
B−V color index 0.241±0.008[3]
Variable type Irregular[4]
Astrometry
Proper motion (μ) RA: −39.284 mas/yr[2]
Dec.: −5.784 mas/yr[2]
Parallax (π)9.3805 ± 0.0427 mas[2]
Distance348 ± 2 ly
(106.6 ± 0.5 pc)
Absolute magnitude (MV)1.34[3]
Orbit[6][7]
Period (P)19.856±0.002 d
Semi-major axis (a)0.22±0.06 AU
Eccentricity (e)0.643±0.006
Inclination (i)17+12
−9°
Periastron epoch (T)2,451,647.539±0.003 HJD
Semi-amplitude (K1)
(primary)		17.8±0.2 km/s
Details
Component A
Mass2.2±0.2[7] M☉
Radius2.7±0.2[7] R☉
Luminosity31[8] L☉
Temperature8,450[8] K
Rotation4.33717±0.00316 d[9]
Rotational velocity (v sin i)12±2[5] km/s
Age2[5] Myr
Component B
Mass1.4±0.3[7] M☉
Other designations
DX Cha, CD−77°528, GC 16412, HD 104237, HIP 58520, SAO 256895, PPM 371328, WDS J11596-7813C[10]
Database references
SIMBADdata

N. Houk and A. P. Cowley found a stellar classification of 'B/A peculiar' for this object in 1975.[14] The following year, K. G. Nehize catalogued it as a star displaying emission lines.[15] In 1988, J. Y. Hu and associates found it to be a candidate Herbig Ae/Be star. This is a class of pre-main sequence stars that recently formed from a molecular cloud.[12] In particular, the star displays an infrared excess associated with a dusty circumstellar shell,[16] and its spectrum closely resembles other Herbig Ae/Be stars such as AB Aurigae and HR 5999.[17] No characteristic molecular cloud was detected nearby, although there are small molecular clumps in the vicinity that may be the remains of a dissipating cloud.[12]

This is the optically brightest Herbig star known, making it a useful object for investigation.[5] Delta scuti-like pulsations have been detected with frequencies of 33.29 and 36.61 cycles per day.[6] It is an X-ray source with a luminosity of 2.69×1030 erg·sec−1, which may originate in a hot corona.[8] DX Cha displays an ultraviolet excess, which indicates the star is still accreting matter at a rate of ≈ 10−8 M☉·yr−1. This inflow is generating a pair of jets emerging from the poles of the star. The circumstellar disk is being viewed from nearly edge on.[5]

Infrared observations in 1996 showed evidence of an infrared source located at an angular separation of 1″,[8] now designated component B. In 2003, optical observations combined with the Chandra X-ray Observatory indicated that five low mass, pre-main sequence objects lie within 5″, equivalent to a projected distance of 1,500 AU from the primary, component A.[18] At least two of these are T Tauri stars.[5] It is uncertain whether all of the nearby companions form a gravitationally bound system with the primary.[11] The close A/B pair display radial velocity variation that indicate this is a double-lined spectroscopic binary with a K-type secondary.[6]

References
  1. "Hipparcos Tools Interactive Data Access". Hipparcos. ESA. Retrieved 8 December 2021.
  2. Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  3. Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv:1108.4971, Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID 119257644.
  4. Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID 125853869.
  5. Grady, C. A.; et al. (June 2004), "The Environment of the Optically Brightest Herbig Ae Star, HD 104237", The Astrophysical Journal, 608 (2): 809–830, Bibcode:2004ApJ...608..809G, doi:10.1086/420763, S2CID 120264519.
  6. Böhm, T.; et al. (December 2004), "Spectroscopic monitoring of the Herbig Ae star HD 104237. I. Multiperiodic stellar oscillations", Astronomy and Astrophysics, 427 (3): 907–922, Bibcode:2004A&A...427..907B, doi:10.1051/0004-6361:20041227.
  7. Garcia, P. J. V.; et al. (April 2013), "Pre-main-sequence binaries with tidally disrupted discs: the Brγ in HD 104237", Monthly Notices of the Royal Astronomical Society, 430 (3): 1839–1853, arXiv:1301.0276, Bibcode:2013MNRAS.430.1839G, doi:10.1093/mnras/stt005.
  8. Skinner, S. L.; Yamauchi, S. (November 1996), "ASCA Observations of HD 104237 (A4e) and the Origin of X-Ray Emission from Herbig AE Stars", Astrophysical Journal, 471 (2): 987, Bibcode:1996ApJ...471..987S, doi:10.1086/178026, S2CID 123243719.
  9. Järvinen, S. P.; et al. (July 2019), "The two magnetic components in the Herbig Ae SB2 system HD 104237", Monthly Notices of the Royal Astronomical Society, 486 (4): 5499–5503, arXiv:1905.05586, Bibcode:2019MNRAS.486.5499J, doi:10.1093/mnras/stz1212.
  10. "DX Cha", SIMBAD, Centre de données astronomiques de Strasbourg, retrieved 2022-05-31.
  11. Dickson-Vandervelde, D. Annie; et al. (February 2021), "Gaia-based Isochronal, Kinematic, and Spatial Analysis of the ɛ Cha Association", The Astronomical Journal, 161 (2): 17, arXiv:2011.06621, Bibcode:2021AJ....161...87D, doi:10.3847/1538-3881/abd0fd, S2CID 234354886, 87
  12. Knee, L. B. G.; Prusti, T. (August 1996), "Molecular gas near HD 104237 and ɛ Chamaeleontis", Astronomy and Astrophysics, 312: 455–462, Bibcode:1996A&A...312..455K.
  13. Sinnott, Roger W.; Perryman, Michael A. C. (1997), Millennium Star Atlas, vol. 2, Sky Publishing Corporation and the European Space Agency, p. 1023, ISBN 0-933346-83-2.
  14. Houk, N.; Cowley, A. P. (1975), "Catalogue of two-dimensional spectral types for the HD stars", University of Michigan, I, Bibcode:1975mcts.book.....H.
  15. Henize, K. G. (April 1976), "Observations of southern emission-line stars", Astrophysical Journal Supplement Series, 30: 491–550, Bibcode:1976ApJS...30..491H, doi:10.1086/190369.
  16. Hu, J. Y.; et al. (January 1989), "Photometric and spectroscopic study of three candidate Herbig Ae/Be stars : HD 37411, HD 100546 and HD 104237", Astronomy and Astrophysics, 208: 213–218, Bibcode:1989A&A...208..213H.
  17. Hu, J. Y.; et al. (August 1991), "IUE observations of the bright Herbig AE star HD 104237", Astronomy and Astrophysics, 248: 150, Bibcode:1991A&A...248..150H.
  18. Feigelson, Eric D.; et al. (December 2003), "The ɛ Chamaeleontis Young Stellar Group and the Characterization of Sparse Stellar Clusters", The Astrophysical Journal, 599 (2): 1207–1222, arXiv:astro-ph/0309059, Bibcode:2003ApJ...599.1207F, doi:10.1086/379365, S2CID 16407429.

Further reading
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