| 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] |
| Distance | 348 ± 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 | |
| Mass | 2.2±0.2 [7] M☉ |
| Radius | 2.7±0.2 [7] R☉ |
| Luminosity | 31 [8] L☉ |
| Temperature | 8,450 [8] K |
| Rotation | 4.33717±0.00316 d [9] |
| Rotational velocity (v sin i) | 12±2 [5] km/s |
| Age | 2 [5] Myr |
| Component B | |
| Mass | 1.4±0.3 [7] M☉ |
| Other designations | |
| DX Cha, CD−77°528, GC 16412, HD 104237, HIP 58520, SAO 256895, PPM 371328, WDS J11596-7813C, WDS J12001-7812 [10] | |
| Database references | |
| SIMBAD | data |
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]
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] Analysis of the Hipparcos data showed that the star's brightness is variable. [18] 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. [19] 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]
