Delta Circus ( lat. Delta Circini , δ Cir ), δ Compass - a multiple star in the constellation Compass . The Delta Compass is also known as HR 5664 and HD 135240 . The total apparent magnitude is + 5.09, the star is located at a distance of about 770 pc (2500 light years ) from the Sun.
| δ Compass | |||
|---|---|---|---|
| Star | |||
 | |||
| Observational data ( Age J2000.0 ) | |||
| Right ascension | |||
| Declination | |||
| Distance | 770 pc [2] | ||
| Visible magnitude ( V ) | 5.09 [3] (5.05 - 5.20 [2] ) | ||
| Constellation | Compass | ||
| Astrometry | |||
| Radial velocity ( R v ) | −17.80 [4] km / s | ||
| Own movement (μ) | RA: −1.90 [1] Dec: −3.06 [1] | ||
| Parallax (π) | 0.89 ± 0.30 [1] mas | ||
| Specifications | |||
| Spectral class | O7.5III (f) [2] (O8IV [2] + O9.5V + B0.5V [5] ) | ||
| Color Index ( B - V ) | −0.06 [3] | ||
| Color Index ( U - B ) | −0.88 [3] | ||
| Variability | Eclipsing Double [2] | ||
| |||
| Database Information | |||
| SIMBAD | data | ||
Content
Multiple Stars
Circular A Delta is a spectral triple star, although the external component was resolved by observations with the VLTI PIONIER instrument. Two internal components form an eclipsing binary star [2] .
Circular Delta B is a 13th magnitude star located 1 arc second from component A. It is not known whether the components are physically connected; a weaker star is a giant or a star of the main sequence of the spectral class G5 [6] .
HD 135160 is a 6th magnitude double Be-star with similar motion to the Delta Circular star and located 4 arc minutes from it. Two of these stars form a pair visible to the naked eye.
System Properties
All three components of Circle A are hot stars with high luminosity. The brightest star belongs to the spectral class O8 and has just begun to leave the main sequence in the process of evolution. It is in close orbit with a star of the main sequence of the spectral class O9.5. Two stars are ellipsoidal and outshine each other with a period of 3.9 days. The total magnitude changes by 0.15.
The third component is a star of spectral class B0.5 of the main sequence in orbit with high eccentricity around a close pair. It is weaker and colder than two close stars, but more massive, so it is assumed that it can be a close binary star [2] .
Notes
- ↑ 1 2 3 4 5 F .; Van Leeuwen. Validation of the new Hipparcos reduction // Astronomy and Astrophysics . - EDP Sciences 2007. - Vol. 474 , no. 2 . - P. 653 . - DOI : 10.1051 / 0004-6361: 20078357 . - . - arXiv : 0708.1752 .
- ↑ 1 2 3 4 5 6 7 Pavel; Mayer; Harmanec, Petr; Sana, Hugues; Le Bouquin, Jean-Baptiste. The Three-body System δ Circini (Eng.) // The Astronomical Journal . - IOP Publishing , 2014. - Vol. 148 , no. 6 . - P. 114 . - DOI : 10.1088 / 0004-6256 / 148/6/114 . - . - arXiv : 1408.1958 .
- ↑ 1 2 3 JR; Ducati. VizieR Online Data Catalog: Catalog of Stellar Photometry in Johnson's 11-color system // CDS / ADC Collection of Electronic Catalogs: journal. - 2002. - Vol. 2237 . - .
- ↑ D .; Pourbaix; Tokovinin, AA; Batten, AH; Fekel, FC; Hartkopf, WI; Levato, H .; Morrell, NI; Torres, G .; Udry, S. SB9: The ninth catalog of spectroscopic binary orbits ( Astronomy and Astrophysics : journal. - EDP Sciences 2004. - Vol. 424 , no. 2 . - P. 727 . - DOI : 10.1051 / 0004-6361: 20041213 . - . - arXiv : astro-ph / 0406573 .
- ↑ Laura R .; Penny; Seyle, Debra; Gies, Douglas R .; Harvin, James A .; Bagnuolo, William G. .; Thaller, ML; Fullerton, AW; Kaper, L. Tomographic Separation of Composite Spectra. VII. The Physical Properties of the Massive Triple System HD 135240 (δ Circini ) // The Astrophysical Journal : journal. - IOP Publishing , 2001. - Vol. 548 , no. 2 . - P. 889 . - DOI : 10.1086 / 319031 . - .
- ↑ KP; Lindroos. A study of visual double stars with early type primaries. IV Astrophysical data (Eng.) // Astronomy and Astrophysics Supplement Series: journal. - 1985. - Vol. 60 . - P. 183 . - .