Rho1 Arae

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ρ1 Arae
Ara constellation map.svg
Red circle.svg
Location of ρ1 Ara (circled)
Observation data
Epoch J2000       Equinox J2000
Constellation Ara
Right ascension 16h 56m 08.8420s [1]
Declination −50° 40′ 29.243″ [1]
Apparent magnitude  (V)6.275 [2]
Characteristics
Spectral type B3 Vnpe
U−B color index −0.691 [2]
B−V color index +0.008 [2]
Astrometry
Radial velocity (Rv)+19 [3]  km/s
Proper motion (μ)RA: −9.403 [1]   mas/yr
Dec.: −9.592 [1]   mas/yr
Parallax (π)3.3089 ± 0.0441  mas [1]
Distance 990 ± 10  ly
(302 ± 4  pc)
Absolute magnitude  (MV)−0.16 [4]
Orbit [5]
Period (P)236.50±0.18 d
Inclination (i)60±7°
Periastron epoch (T)HJD 2458672.10±0.72
Semi-amplitude (K1)
(primary)		4.33±0.05 km/s
Semi-amplitude (K2)
(secondary)		52.83±1.49 km/s
Details
ρ1 Ara A
Mass 6.5±1.3 [5]   M☉
Radius 4.21±0.20 [6]   R☉
Luminosity 1,418 [7]   L☉
Surface gravity (log g)3.75 [8]   cgs
Temperature 19,800 [8]   K
Rotational velocity (v sin i)370±10 [9]  km/s
Age 18.4±1.5 [10]   Myr
ρ1 Ara B
Mass 0.53±0.11 [5]   M☉
Radius 0.27±0.04 [6]   R☉
Luminosity204 [6]   L☉
Temperature 42,000 [6]   K
Other designations
ρ1 Ara, V846 Arae, CD−50 10905, GC 22790, HD  152478, HIP 82868, HR 6274, NSV 8047, SAO 244280 [11]
Database references
SIMBAD data

Rho1 Arae is the Bayer designation for a star in the southern constellation of Ara. Unusually for a star with a Bayer designation, it was not catalogued by Bayer in his Uranometria . It was instead first catalogued by Nicolas Lacaille, in his Coelum Australe Stelliferum published in 1763. This star gained the Bayer designation of Rho1 Arae in Bode's Uranographia , published in 1801. Rho1 Arae is one of the dimmest stars with a Bayer designation, having an apparent visual magnitude of just +6.275 [2] According to the Bortle Dark-Sky Scale, this means the star is just barely visible to the naked eye in dark rural skies. Based upon parallax measurements, it is about 990 light-years (302 parsecs ) distant from the Sun. [1]

A light curve for V846 Arae, plotted from TESS data V846AraLightCurve.png
A light curve for V846 Arae, plotted from TESS data

Hipparcos data revealed that Rho1 Arae is a variable star. It was given its variable star designation, V846 Arae, in 1999. [13] This is a spectroscopic binary system, which means that the presence of an orbiting companion is indicated by shifts in the spectrum. The primary star is a Be star, while the secondary star is a subdwarf O star; they orbit each other with a period of about 236.50 days. [5] The combined spectrum of this system matches a stellar classification of B3 Vnpe, which may indicate the primary is a B-type main-sequence star. The 'e' suffix indicates the presence of emission lines from the primary Be star. For Rho1 Arae, the emission lines are prominent and variable. [9] The primary star is spinning rapidly with a projected rotational velocity of 370±10 km/s, which makes it difficult to obtain reliable orbital elements. [9]

Rho1 Arae has a peculiar velocity of 27.4±4.9 km/s relative to its neighbors, [10] making it a runaway star system. A scenario that it was ejected from the Scorpius–Centaurus OB association as a result of a past supernova explosion seems unlikely because of its binarity. [9]

References

  1. 1 2 3 4 5 6 Vallenari, A.; et al. (Gaia collaboration) (2023). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy and Astrophysics. 674: A1. arXiv: 2208.00211 . Bibcode:2023A&A...674A...1G. doi: 10.1051/0004-6361/202243940 . S2CID   244398875. Gaia DR3 record for this source at VizieR.
  2. 1 2 3 4 Kozok, J. R. (September 1985), "Photometric observations of emission B-stars in the southern Milky Way", Astronomy and Astrophysics Supplement Series, 61: 387–405, Bibcode:1985A&AS...61..387K.
  3. ↑ 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.
  4. ↑ 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.
  5. 1 2 3 4 Wang, Luqian; Gies, Douglas R.; Peters, Geraldine J.; Han, Zhanwen (April 2023), "The Orbital and Physical Properties of Five Southern Be+sdO Binary Systems", The Astronomical Journal, 165 (5): 203, arXiv: 2303.12616 , Bibcode:2023AJ....165..203W, doi: 10.3847/1538-3881/acc6ca , ISSN   1538-3881.
  6. 1 2 3 4 Wang, Luqian; Gies, Douglas R.; Peters, Geraldine J.; Götberg, Ylva; Chojnowski, S. Drew; Lester, Kathryn V.; Howell, Steve B. (2021), "The Detection and Characterization of Be+sdO Binaries from HST/STIS FUV Spectroscopy", The Astronomical Journal, 161 (5): 248, arXiv: 2103.13642 , Bibcode:2021AJ....161..248W, doi: 10.3847/1538-3881/abf144 .
  7. ↑ Hohle, M. M.; Neuhäuser, R.; Schutz, B. F. (April 2010), "Masses and luminosities of O- and B-type stars and red supergiants", Astronomische Nachrichten, 331 (4): 349, arXiv: 1003.2335 , Bibcode:2010AN....331..349H, doi:10.1002/asna.200911355, S2CID   111387483.
  8. 1 2 Soubiran, C.; Le Campion, J.-F.; Cayrel de Strobel, G.; Caillo, A. (June 2010), "The PASTEL catalogue of stellar parameters", Astronomy and Astrophysics, 515: A111, arXiv: 1004.1069 , Bibcode:2010A&A...515A.111S, doi:10.1051/0004-6361/201014247, S2CID   118362423.
  9. 1 2 3 4 Jilinski, E.; et al. (September 2010), "A Dynamical Study of Suspected Runaway Stars as Traces of Past Supernova Explosions in the Region of the Scorpius–Centaurus OB Association", The Astrophysical Journal, 721 (1): 469–477, Bibcode:2010ApJ...721..469J, doi: 10.1088/0004-637X/721/1/469 .
  10. 1 2 Tetzlaff, N.; Neuhäuser, R.; Hohle, M. M. (January 2011), "A catalogue of young runaway Hipparcos stars within 3 kpc from the Sun", Monthly Notices of the Royal Astronomical Society , 410 (1): 190–200, arXiv: 1007.4883 , Bibcode:2011MNRAS.410..190T, doi: 10.1111/j.1365-2966.2010.17434.x , S2CID   118629873.
  11. ↑ "rho01 Ara", SIMBAD , Centre de données astronomiques de Strasbourg , retrieved 2012-08-01.
  12. ↑ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, retrieved 8 December 2021.
  13. ↑ Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Frolov, M. S.; Antipin, S. V.; Kireeva, N. N.; Pastukhova, E. N. (January 1999), "The 74th Special Name-list of Variable Stars", Information Bulletin on Variable Stars, 4659: 1, Bibcode:1999IBVS.4659....1K.
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