R Arae is an Algol-type eclipsing binary in the constellation Ara. Located approximately 298 parsecs (970 ly) distant, it normally shines at magnitude 6.17, but during eclipses can fall as low as magnitude 7.32.[3] When an eclipse is not occurring, it will be faintly visible to the naked eye under ideal observing conditions.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Ara |
| Right ascension | 16h 39m 44.726s[2] |
| Declination | −56° 59′ 39.92″[2] |
| Apparent magnitude (V) | 6.17 (- 6.20) - 7.32[3] |
| Characteristics | |
| Spectral type | B9Vp[4] (B5V + F1IV[5]) |
| B−V color index | 0.10[5] |
| Variable type | Algol[4] |
| Astrometry | |
| Radial velocity (Rv) | +5.5[5] km/s |
| Proper motion (μ) | RA: −4.991[6] mas/yr Dec.: −17.810[6] mas/yr |
| Parallax (π) | 3.3603 ± 0.0647 mas[6] |
| Distance | 970 ± 20 ly (298 ± 6 pc) |
| Absolute magnitude (MV) | −0.48 + 0.00[5] |
| Orbit[5] | |
| Period (P) | 4.425 d |
| Eccentricity (e) | 0 |
| Inclination (i) | 78.0° |
| Semi-amplitude (K1) (primary) | 55.3 km/s |
| Semi-amplitude (K2) (secondary) | 181.6 km/s |
| Details[5] | |
| A | |
| Mass | 5.0 M☉ |
| Radius | 3.41 R☉ |
| Luminosity | 257 L☉ |
| Surface gravity (log g) | 4.07 cgs |
| Temperature | 12,500 K |
| Rotational velocity (v sin i) | 202[5] km/s |
| B | |
| Mass | 1.5 M☉ |
| Radius | 5.97 R☉ |
| Luminosity | 78 L☉ |
| Surface gravity (log g) | 3.07 cgs |
| Temperature | 7,000 K |
| Rotational velocity (v sin i) | 73 km/s |
| Other designations | |
| Database references | |
| SIMBAD | data |
In 1892, R Ara was discovered to be an eclipsing binary by Alexander William Roberts at Lovedale observatory in South Africa. The discovery was published in 1894.[7] Roberts referred to the star as "(5949) Arae", its designation as an unconfirmed variable star in Seth Carlo Chandler's catalog of variable stars.[8] It was listed with its modern variable star designation, R Arae, in Annie Jump Cannon's 1907 Second Catalogue of Variable Stars.[9]
It has been suggested by multiple studies that mass transfer is occurring between the two stars of this system,[10][11] and the period of eclipses seems to be increasing over time.[11] The primary is a blue-white main sequence star of spectral type B5V that is 5 times as massive as the Sun, while the secondary is a yellow-white star of spectral type F1IV that is 1.5 times as massive as the Sun. Stellar material is being stripped off the secondary and accreting on the primary.[5]
R Arae has an 8th-magnitude companion 3″ away.[5] The companion star is at a similar distance.[12]
References
edit- ^ Blane, D.; Blackford, M. G.; Budding, E.; Reed, P. A. (May 2019). "New light on R Arae" (PDF). Information Bulletin on Variable Stars. 6267 (1). Bibcode:2019IBVS.6267....1B. doi:10.22444/IBVS.6267. S2CID 202939949. Retrieved 24 October 2021.
- ^ a b Van Leeuwen, F. (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 VSX (25 October 2010). "R Arae". AAVSO Website. American Association of Variable Star Observers. Retrieved 30 June 2014.
- ^ a b Samus, N. N.; Durlevich, O. V.; et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S. 1: B/gcvs. Bibcode:2009yCat....102025S.
- ^ a b c d e f g h i Bakıș, H.; Bakıș, V.; Eker, Z.; Demircan, O. (2016). "Active binary R Arae revisited: Bringing the secondary component to light and physical modelling of the circumstellar material". Monthly Notices of the Royal Astronomical Society. 458 (1): 508–516. Bibcode:2016MNRAS.458..508B. doi:10.1093/mnras/stw320.
- ^ a b c Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- ^ Roberts, Alexander W. (October 1894). "Variation of (3416)-Velorum and (5949)-Arae". Astronomical Journal. 14 (327): 113–117. Bibcode:1894AJ.....14..113R. doi:10.1086/102103. Retrieved 24 November 2024.
- ^ Chandler, S. C. (August 1893). "Second catalogue of variable stars". Astronomical Journal. 13 (300): 89–110. Bibcode:1893AJ.....13...89C. doi:10.1086/101922. Retrieved 24 November 2024.
- ^ Cannon, Annie J. (1907). "Second catalogue of variable stars". Annals of Harvard College Observatory. 55: 1–94. Bibcode:1907AnHar..55....1C. Retrieved 21 November 2024.
- ^ Nield, K. M. (1991). "Observations and analysis of the Southern binary R Arae". Astrophysics and Space Science. 180 (2): 233–252. Bibcode:1991Ap&SS.180..233N. doi:10.1007/BF00648180. S2CID 122896654.
- ^ a b Reed, P. A.; McCluskey Jr., G. E.; Kondo, Y.; Sahade, J.; Guinan, E. F.; GiméNez, A.; Caton, D. B.; Reichart, D. E.; Ivarsen, K. M.; Nysewander, M. C. (2010). "Ultraviolet study of the active interacting binary star R Arae using archivalIUEdata". Monthly Notices of the Royal Astronomical Society. 401 (2): 913. arXiv:0909.4047. Bibcode:2010MNRAS.401..913R. doi:10.1111/j.1365-2966.2009.15741.x. S2CID 15237238.
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.