 HST image of B90, the star can be seen near the centre. | |
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Dorado |
| Right ascension | 05 24 19.3095 |
| Declination | −69° 38′ 49.374″ |
| Apparent magnitude (V) | 14.271±0.194 |
| Characteristics | |
| Evolutionary stage | Red supergiant |
| Spectral type | M3−4 I |
| Apparent magnitude (U) | 19.519 |
| Apparent magnitude (B) | 16.688 |
| Apparent magnitude (R) | 11 |
| Apparent magnitude (G) | 12.135779±0.004246 |
| Apparent magnitude (I) | 10.804±0.105 |
| Apparent magnitude (J) | 8.360±0.018 |
| Apparent magnitude (H) | 7.375±0.038 |
| Apparent magnitude (K) | 6.809±0.023 |
| Variable type | SRc |
| Astrometry | |
| Radial velocity (Rv) | 263.49±1.02 km/s |
| Proper motion (μ) | RA: 1.913±0.037 mas/yr Dec.: 0.411±0.034 mas/yr |
| Parallax (π) | 0.0457 ± 0.027 mas |
| Distance | 45,590 pc |
| Details | |
| Mass | 25 (initial) M☉ |
| Radius | 1,000+70 −80 – 1,210 R☉ |
| Luminosity | 209,000±5,000 L☉ |
| Surface gravity (log g) | −0.2+0.20 −0.30 cgs |
| Temperature | 3,550±40 – 3,900+150 −100 K |
| Metallicity | 0.0+0.2 −0.1 dex |
| Other designations | |
| WOH S264, LI-LMC 976, MSX LMC 461, RM 1-339, SP77 47-10 | |
| Database references | |
| SIMBAD | data |
B90 (often referred to as B90) is a large, highly luminous red supergiant star similar to Betelgeuse in the Large Magellanic Cloud.
Discovery
B90 was discovered in 1956 by Karl Gordon Henize in a catalogue of H-alpha emission stars and nebulae in the Large Magellanic Cloud. He designated it LHA 120-N 132E, indicating emission line nebula 132E on plate 120. The LHA is originally LHα, standing for H-alpha emission objects identified at the Lamont-Hussey Observatory.
Properties
B90 is believed to be one of the largest, most luminous red supergiants in the Large Magellanic Cloud. Its luminosity was first measured to be of more than 280,000 solar luminosities and a radius of around 1,390 solar radii, although a more detailed study put it at 209,000 L☉ and 1,210 R☉.
Mass-loss
The star has episodic mass-loss with a high rate of 4.4+5.1
−1.7×10 M☉ yr and a nebula of ~1 pc (~3 ly) surrounding the star. This nebula could indicate that the star has a bow shock, which supplies evidence that the star does undergo episodic mass-loss, which makes it more likely that this is the case for almost all red supergiants.
The variability of the star and possible "great dimming" events are also consistent with episodic mass-loss, similar to those of Betelgeuse and RW Cephei. The rebrightening of B90, just like RW Cephei, took twice as long as that of Betelgeuse which could indicate a relation between the time taken and the radius of red supergiants, where B90 is 1,000 R☉ – 1,210 R☉.
Velocity
B90 has a very high velocity of (19 – 27) ± 11 km s towards its nebular bar, therefore proving that it is a "walkaway" star. This potentially makes the possibility that it has a bow shock more likely.
See also
Notes
- Discrepancy in radius is caused by possible underestimation of the effective temperature measured using Titanium(II) oxide bands.
References
- ^ "[W60] B90". Université de Strasbourg.
- Ulaczyk, K.; Szymański, M. K.; Udalski, A.; Kubiak, M.; Pietrzyński, G.; Soszyński, I.; Wyrzykowski, Ł.; Poleski, R.; Gieren, W.; Walker, A. R.; Garcia-Varela, A. (20 June 2013). "Variable Stars from the OGLE-III Shallow Survey in the Large Magellanic Cloud". Acta Astronomica. 63 (2): 159–179. arXiv:1306.4802. Bibcode:2013AcA....63..159U.
- ^ Munoz-Sanchez, G.; de Wit, S.; Bonanos, A. Z.; Antoniadis, K.; Boutsia, K.; Boumis, P.; Christodoulou, E.; Kalitsounaki, M.; Udalski, A. (21 May 2024). "Episodic mass loss in the very luminous red supergiant B90 in the Large Magellanic Cloud". arXiv:2405.11019 .
- ^ Kamath, D.; Wood, P. R.; Van Winckel, H. (4 August 2015). "Optically visible post-AGB stars, post-RGB stars and young stellar objects in the Large Magellanic Cloud". The Royal Astronomical Society. 454 (2): 1468–1502. arXiv:1508.00670. Bibcode:2015MNRAS.454.1468K. doi:10.1093/mnras/stv1202.
- ^ Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics. 649: A1. arXiv:2012.01533. Bibcode:2021A&A...649A...1G. doi:10.1051/0004-6361/202039657. S2CID 227254300. (Erratum: doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
- ^ 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.
- Pietrzyński, G.; Graczyk, D.; Gallenne, A.; Gieren, W.; Thompson, I. B.; Pilecki, B.; Karczmarek, P.; Górski, M.; Suchomska, K.; Taormina, M.; Zgirski, B.; Wielgórski, P.; Kołaczkowski, Z.; Konorski, P.; Villanova, S.; Nardetto, N.; Kervella, P.; Bresolin, F.; Kudritzki, R. P.; Storm, J.; Smolec, R.; Narloch, W. (2019). "A distance to the Large Magellanic Cloud that is precise to one per cent". Nature. 567 (7747): 200–203. arXiv:1903.08096. Bibcode:2019Natur.567..200P. doi:10.1038/s41586-019-0999-4. PMID 30867610. S2CID 76660316.
- ^ de Wit, S.; Bonanos, A.Z.; Tramper, F.; Yang, M.; Maravelias, G.; Boutsia, K.; Britavskiy, N.; Zapartas, E. (2023). "Properties of luminous red supergiant stars in the Magellanic Clouds". Astronomy and Astrophysics. 669: 17. arXiv:2209.11239. Bibcode:2023A&A...669A..86D. doi:10.1051/0004-6361/202243394. S2CID 252519285.
- Henize, Karl G. (1956-05-05). "Catalogues of Hα-emission Stars and Nebulae in the Magellanic Clouds". Astrophysical Journal. 2: 315. Bibcode:1956ApJS....2..315H. doi:10.1086/190025.
