| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Corona Australis[1] |
| Right ascension | 18h 24m 18.23949s[2] |
| Declination | −44° 06′ 36.9186″[2] |
| Apparent magnitude (V) | 5.24[1] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | B3 V[3] |
| B−V color index | −0.163±0.004[1] |
| Astrometry | |
| Radial velocity (Rv) | +0.00±7.40[1] km/s |
| Proper motion (μ) | RA: −1.659[2] mas/yr Dec.: −22,022[2] mas/yr |
| Parallax (π) | 5.5671±0.1134 mas[2] |
| Distance | 590 ± 10 ly (180 ± 4 pc) |
| Absolute magnitude (MV) | −0.63[1] |
| Details | |
| Mass | 4.5[4] M☉ |
| Radius | 3.9[2] R☉ |
| Luminosity | 389[4] L☉ |
| Surface gravity (log g) | 4.43[5] cgs |
| Temperature | 15,803[5] K |
| Rotation | 27.2 days[6] |
| Rotational velocity (v sin i) | 248±12[7] km/s |
| Age | 103[8] Myr |
| Other designations | |
| CD−44°12569, FK5 3461, HD 168905, HIP 90200, HR 6875, SAO 228982, WDS J18243-4407A[9] | |
| Database references | |
| SIMBAD | data |
HR 6875, previously known as Sigma Telescopii, is a single[10] star in the constellation Corona Australis. It has a blue-white hue and is dimly visible to the naked eye with an apparent visual magnitude of 5.24.[1] This object is located at a distance of approximately 590 light years from the Sun based on parallax.[2] It is listed as a member of the Sco OB2 association.[7]
This is a hot B-type main-sequence star with a stellar classification of B3 V.[3] It is around 103[8] million years old and is spinning rapidly with a projected rotational velocity of 248 km/s or perhaps higher.[7] The star has 4.5 times the mass of the Sun[4] and about four times the Sun's radius.[2] It is radiating nearly 400 the luminosity of the Sun[4] from its photosphere at an effective temperature of 15,803 K[5]
A magnitude 10.13 visual companion is located at an angular separation of 74″ along a position angle of 162°.[11]
References
- ^ a b c d e f 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. XHIP record for this object at VizieR.
- ^ a b c d e f g h i 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.
- ^ a b Houk, Nancy (1978), Michigan catalogue of two-dimensional spectral types for the HD stars, vol. 2, Ann Arbor: Dept. of Astronomy, University of Michigan, Bibcode:1978mcts.book.....H.
- ^ a b c d Quintana, Alexis L.; Wright, Nicholas J.; Martínez García, Juan (2025). "A census of OB stars within 1 KPC and the star formation and core collapse supernova rates of the Milky Way". Monthly Notices of the Royal Astronomical Society. 538 (3): 1367. arXiv:2503.08286. Bibcode:2025MNRAS.538.1367Q. doi:10.1093/mnras/staf083.
- ^ a b c Cardiel, Nicolás; Zamorano, Jaime; Bará, Salvador; Sánchez De Miguel, Alejandro; Cabello, Cristina; Gallego, Jesús; García, Lucía; González, Rafael; Izquierdo, Jaime; Pascual, Sergio; Robles, José; Sánchez, Ainhoa; Tapia, Carlos (2021). "Synthetic RGB photometry of bright stars: Definition of the standard photometric system and UCM library of spectrophotometric spectra". Monthly Notices of the Royal Astronomical Society. 504 (3): 3730. arXiv:2103.17009. Bibcode:2021MNRAS.504.3730C. doi:10.1093/mnras/stab997.
- ^ Oelkers, Ryan J.; Rodriguez, Joseph E.; Stassun, Keivan G.; Pepper, Joshua; Somers, Garrett; Kafka, Stella; Stevens, Daniel J.; Beatty, Thomas G.; Siverd, Robert J.; Lund, Michael B.; Kuhn, Rudolf B.; James, David; Gaudi, B. Scott (2018). "Variability Properties of Four Million Sources in the TESS Input Catalog Observed with the Kilodegree Extremely Little Telescope Survey". The Astronomical Journal. 155 (1): 39. arXiv:1711.03608. Bibcode:2018AJ....155...39O. doi:10.3847/1538-3881/aa9bf4.
- ^ a b c Brown, A. G. A.; Verschueren, W. (1997), "High S/N Echelle spectroscopy in young stellar groups. II. Rotational velocities of early-type stars in SCO OB2", Astronomy and Astrophysics, 319: 811, arXiv:astro-ph/9608089, Bibcode:1997A&A...319..811B.
- ^ a b Gontcharov, G. A. (November 2012), "Spatial distribution and kinematics of OB stars", Astronomy Letters, 38 (11): 694–706, arXiv:1606.09028, Bibcode:2012AstL...38..694G, doi:10.1134/S1063773712110035, S2CID 119108982.
- ^ "HD 168905". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2018-07-14.
- ^ 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.
- ^ Mason, B. D.; et al. (2014), "The Washington Visual Double Star Catalog", The Astronomical Journal, 122 (6): 3466, Bibcode:2001AJ....122.3466M, doi:10.1086/323920, retrieved 2015-07-22
