Zeta1 Scorpii
  | |
| Observation data Epoch J2000.0 Equinox J2000.0 (ICRS) | |
|---|---|
| Constellation | Scorpius |
| Right ascension | 16h 53m 59.72713s[1] |
| Declination | −42° 21′ 43.3073″[1] |
| Apparent magnitude (V) | 4.705[2] (4.66 to 4.86)[3] |
| Characteristics | |
| Spectral type | B1.5 Ia+[4] |
| U−B color index | −0.567[2] |
| B−V color index | +0.480[2] |
| Variable type | Luminous blue variable[5] |
| Astrometry | |
| Radial velocity (Rv) | −26.0[6] km/s |
| Proper motion (μ) | RA: −0.094 mas/yr[1] Dec.: −3.368 mas/yr[1] |
| Parallax (π) | 0.5855±0.1176 mas[1] |
| Distance | approx. 6,000 ly (approx. 1,700 pc) |
| Absolute magnitude (MV) | −8.5[4] |
| Details | |
| Mass | 36 to 53[4] M☉ |
| Radius | 159+83 −34[7] R☉ |
| Luminosity (bolometric) | (1.0–1.6)×106[7] L☉ |
| Surface gravity (log g) | 1.7[4] cgs |
| Temperature | 17,000–19,000[7] K |
| Rotational velocity (v sin i) | 60[8] km/s |
| Age | 6.5±0.1[9] Myr |
| Other designations | |
| ζ1 Sco, CD−42 11633, CPD−42 7545, GC 22730, HD 152236, HIP 82671, HR 6262, PPM 322342, SAO 227375.[10] | |
| Database references | |
| SIMBAD | data |
Zeta1 Scorpii (Zeta1 Sco, ζ1 Scorpii, ζ1 Sco) is a binary star[7] in the constellation of Scorpius, composed by an B-type hypergiant star as the primary, and a secondary of which little is known. It has an apparent visual magnitude which varies between 4.66 and 4.86.[3] It is a member of the Scorpius OB1 association, and potentially of the open star cluster NGC 6231,[11] also known as the "Northern jewel box" cluster.
Characteristics
[edit]
ζ1 Scorpii's primary is a luminous blue variable according to its luminosity and spectral appearance,[13] yet is has not shown the characteristic types of variability, hence is classified as a dormant LBV.[5] It has around 36 times as massive as the Sun[4] and is one of the most luminous stars known in the Galaxy, with an estimated bolometric luminosity between 1 and 1.6 million times that of the Sun and a radius around 160 times that of the Sun.[7] The stellar wind from this supergiant is expelling matter from the star at the rate of 1.55 × 10−6 solar masses per year, or roughly the equivalent to the Sun's mass every 640,000 years.[4]
The secondary has been detected using interferometry, and its discovery was announced in 2021. As of 2021[update], it has an angular separation of 11.54±0.10 mas along a position angle of 283.22°+0.76°
−0.34°. It is 6.3 magnitudes fainter than the primary.[7]
ζ1 Scorpii forms a naked eye double with ζ2 Scorpii, but the stars are merely coincidentally near in the line of sight from Earth. ζ2 is a mere 135 light-years distant and much less luminous in real terms. ζ1 Scorpii can also be distinguished from ζ2, due to the latter's orange hue especially in long-exposure photographs.
References
[edit]- ^ a b c d 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 c 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.
- ^ a b "Query= zet 1 Sco". General Catalogue of Variable Stars. Lomonosov Moscow State University. Archived from the original on 2012-03-07. Retrieved November 20, 2009.
- ^ a b c d e f Clark, J. S.; Najarro, F.; Negueruela, I.; Ritchie, B. W.; Urbaneja, M. A.; Howarth, I. D. (2012). "On the nature of the galactic early-B hypergiants". Astronomy & Astrophysics. 541: A145. arXiv:1202.3991. Bibcode:2012A&A...541A.145C. doi:10.1051/0004-6361/201117472. S2CID 11978733.
- ^ a b Spejcher, Becca; Richardson, Noel D.; Pablo, Herbert; Beltran, Marina; Butler, Payton; Avila, Eddie (January 1, 2025). "An Investigation into the Variability of Luminous Blue Variable Stars with TESS". The Astronomical Journal. 169 (3): 128. arXiv:2501.00240. doi:10.3847/1538-3881/ada561. ISSN 1538-3881.
- ^ 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.
- ^ a b c d e f Mahy, L.; Lanthermann, C.; Hutsemékers, D.; Kluska, J.; Lobel, A.; Manick, R.; Miszalski, B.; Reggiani, M.; Sana, H.; Gosset, E. (January 2022). "Multiplicity of Galactic luminous blue variable stars". Astronomy and Astrophysics. 657: A4. arXiv:2105.12380. Bibcode:2022A&A...657A...4M. doi:10.1051/0004-6361/202040062. ISSN 0004-6361.
- ^ Bernacca, P. L.; Perinotto, M. (1970). "A catalogue of stellar rotational velocities". Contributi Osservatorio Astronomico di Padova in Asiago. 239 (1): 1. Bibcode:1970CoAsi.239....1B.
- ^ 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.
- ^ HIP 82671 -- Emission-line Star, database entry, SIMBAD. Accessed on line November 20, 2009.
- ^ "Zeta-1 Sco". stars.astro.illinois.edu. Archived from the original on 2009-10-17. Retrieved November 20, 2009.
- ^ Sterken, C.; de Groot, M.; van Genderen, A. M. (October 1997). "Cyclicities in the light variations of LBVs I. The multi-periodic behaviour of the LBV candidate ζ1 Sco". Astronomy and Astrophysics. 326: 640–646. Bibcode:1997A&A...326..640S. Retrieved 20 October 2022.
- ^ Nazé, Y.; Rauw, G.; Hutsemékers, D. (2012). "The first X-ray survey of Galactic luminous blue variables". Astronomy & Astrophysics. 538: A47. arXiv:1111.6375. Bibcode:2012A&A...538A..47N. doi:10.1051/0004-6361/201118040. S2CID 43688343.
