HD 157661 is the Henry Draper Catalogue designation for a likely triple star[3] in the southern constellation of Ara. With a measured annual parallax of 5.13 mas,[1] is located at a distance of approximately 640 light-years (200 parsecs) from Earth. The combined apparent visual magnitude of the stars is 5.29,[2] which means it is faintly visible to the naked eye.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ara |
| Right ascension | 17h 26m 51.97802s[1] |
| Declination | –45° 50′ 34.9096″[1] |
| Apparent magnitude (V) | 5.29[2] (5.70/6.46/7.6)[3] |
| Characteristics | |
| Spectral type | B7V + B9.5V + A0V[3] |
| U−B color index | –0.34[2] |
| B−V color index | –0.07[2] |
| R−I color index | –0.03 |
| Astrometry | |
| Radial velocity (Rv) | +8[4] km/s |
| Proper motion (μ) | RA: –6.46[1] mas/yr Dec.: –27.91[1] mas/yr |
| Parallax (π) | 5.13 ± 0.72 mas[1] |
| Distance | approx. 640 ly (approx. 190 pc) |
| Other designations | |
| Database references | |
| SIMBAD | data |
The inner components of this system consist of a pair of B-type main sequence stars. The brighter star has a magnitude of 5.70 and a stellar classification of B7 V. At an angular separation of 2.115 arcseconds is the magnitude 6.46 secondary component, which has a classification of B9.5 V. A third member of the system is a 7.6 magnitude A-type star at a separation of 103 arcseconds.[3]
References
edit- ^ a b c d e f van Leeuwen, F. (November 2007), "Validation of the new Hipparcos reduction", Astronomy and Astrophysics, 474 (2): 653–664, arXiv:0708.1752, Bibcode:2007A&A...474..653V, doi:10.1051/0004-6361:20078357, S2CID 18759600.
- ^ a b c d Nicolet, B. (1978), "Photoelectric photometric Catalogue of homogeneous measurements in the UBV System", Astronomy and Astrophysics Supplement Series, 34: 1–49, Bibcode:1978A&AS...34....1N.
- ^ a b c d Eggleton, P. P.; Tokovinin, A. A. (September 2008), "A catalogue of multiplicity among bright stellar systems", Monthly Notices of the Royal Astronomical Society, 389 (2): 869–879, arXiv:0806.2878, Bibcode:2008MNRAS.389..869E, doi:10.1111/j.1365-2966.2008.13596.x, S2CID 14878976.
- ^ Evans, D. S. (June 20–24, 1966), "The Revision of the General Catalogue of Radial Velocities", in Batten, Alan Henry; Heard, John Frederick (eds.), Determination of Radial Velocities and their Applications, Proceedings from IAU Symposium no. 30, vol. 30, University of Toronto: International Astronomical Union, p. 57, Bibcode:1967IAUS...30...57E.
- ^ "CCDM J17268-4550AB". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2012-08-03.
External links
edit- VizieR Detailed Page: HR 6477 Hoffleit, D., Warren, Jr., W. H., (1991). The Bright Star Catalogue, (5th Revised Ed), CDS.
- VizieR Detailed Page: CCDM 17268-4550 Dommanget J., (2002) Catalog of Components of Double & Multiple stars, CDS.
- Aladin previewer: Image of SV* ZI 1312