 Artist's impression of BX Trianguli. The planet is not represented here. | |
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Triangulum |
| Right ascension | 02 20 50.85419 |
| Declination | +33° 20′ 47.4683″ |
| Apparent magnitude (V) | 13.366±0.006 |
| Characteristics | |
| Evolutionary stage | Red dwarf |
| Spectral type | M2 |
| Variable type | Eclipsing binary + Flare star |
| Astrometry | |
| Proper motion (μ) | RA: +144.250 mas/yr Dec.: –111.210 mas/yr |
| Parallax (π) | 18.9896 ± 0.0259 mas |
| Distance | 171.8 ± 0.2 ly (52.66 ± 0.07 pc) |
| Orbit | |
| Primary | A |
| Companion | B |
| Period (P) | 0.1926 days (4.62 hours) |
| Semi-major axis (a) | 1.33±0.03 R☉ |
| Inclination (i) | 66.89±0.45° |
| Details | |
| A | |
| Mass | 0.578±0.04 M☉ |
| Radius | 0.59±0.01 R☉ |
| Luminosity | 0.053 L☉ |
| Temperature | 3,735 K |
| B | |
| Mass | 0.28±0.02 M☉ |
| Radius | 0.27±0.01 R☉ |
| Luminosity | 0.007 L☉ |
| Temperature | 3,359±28 K |
| Other designations | |
| BX Tri, LSPM J0220+3320, GSC 02314-00530, 2MASS J02205082+3320479, NSVS 6550671 | |
| Database references | |
| SIMBAD | data |
BX Trianguli is a binary system made up of two red dwarfs, in the constellation Triangulum. Both stars eclipse each other and have an orbital period of four hours and 40 minutes. They are located at around 170 light-years from Earth based upon parallax measurements.
Variability
This is an eclipsing binary variable, first identified by the Northern Sky Variability Survey survey in 2004 and given its variable-star designation BX Trianguli in 2010. Both stars in the system eclipse each other as seen from Earth, causing the brightness of the system to drop from a magnitude of 12.35 to 12.6/12.7 on the secondary/primary ecplise respectively.
The system has also been identified as a flare star. Six flares were recorded between 2014 and 2017, the strongest being identified in November 2014, four times stronger than a typical superflare. The large occurrence of flares on BX Trianguli is the highest among eclipsing binaries after Castor C (YY Geminorum) and might be related to rapid mass transfer between the components. These flares likely occur on BX Trianguli B.
BX Trianguli also has strong magnetic activity, manifested as starspots on the primary's surface and Hα emission.
Characteristics
This system is composed of two red dwarfs, which have an ultra-short period of just 4.6 hours and a separation of 1.33 solar radii, or two and a half times the distance to the Moon. This orbit is one of the shortest known among main sequence stars. The primary star, named BX Trianguli A, has a mass equivalent to 58% the solar mass and a radius equivalent to 60% of the solar radius, while the secondary BX Trianguli B is smaller, at 28% and 27% of the solar mass and radius respectively. BX Trianguli has a semi-detached configuration, with the "A" component being distorted due to gravitational interactions with its partner.
There is a star that could be bound to this system, called USNO-B1 1233−0046425, at roughly 3500 astronomical units of distance.
Planetary system
A circumbinary planet was discovered after analysis of eclipse timing variations by a high school student and his teacher. After rulling out alternative expanations for the eclipse timing variations, the two discoverers found that they are caused by a seven-Jupiter-mass planet at a separation of 4.5 astronomical units (670,000,000 km), with an orbital eccentricity of 0.4. The findings were published in 2024 at the American Association of Variable Star Observers's 113th Annual Meeting.
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | 7.5 MJ | 4.5 | — | 0.4 | — | — |
References
- ^ 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.
Gaia ID is acessible via the TESS Input Catalog - Zacharias, N.; Finch, C. T.; Girard, T. M.; Henden, A.; Bartlett, J. L.; Monet, D. G.; Zacharias, M. I. (2013-01-14). "The fourth US Naval Observatory CCD Astrograph Catalog (UCAC4)". The Astronomical Journal. 145 (2): 44. arXiv:1212.6182. Bibcode:2013AJ....145...44Z. doi:10.1088/0004-6256/145/2/44. ISSN 0004-6256.
- Bowler, Brendan P.; Hinkley, Sasha; Ziegler, Carl; Baranec, Christoph; Gizis, John E.; Law, Nicholas M.; Liu, Michael C.; Shah, Viyang S.; Shkolnik, Evgenya L.; Riaz, Basmah; Riddle, Reed (2019-05-01). "The Elusive Majority of Young Moving Groups. I. Young Binaries and Lithium-rich Stars in the Solar Neighborhood". The Astrophysical Journal. 877 (1): 60. arXiv:1903.06303. Bibcode:2019ApJ...877...60B. doi:10.3847/1538-4357/ab1018. ISSN 0004-637X. BX Trianguli's database entry at VizieR.
- ^ Zhang, Li-Yun; Pi, Qing-feng; Yang, Yuan-Gui (2014-08-01). "Magnetic activity and orbital periods of five low-mass eclipsing binaries". Monthly Notices of the Royal Astronomical Society. 442 (3): 2620–2636. Bibcode:2014MNRAS.442.2620Z. doi:10.1093/mnras/stu964. ISSN 0035-8711.
- ^ Luo, ChangQing; Zhang, XiaoBin; Wang, Kun; Liu, Chao; Fang, Xiangsong; Zhang, Chunguang; Deng, Licai; Nie, Jundan; Fox-Machado, Lester; Luo, Yangping; Niu, Hubiao (2019-02-01). "Frequent Flare Events on the Short-period M-type Eclipsing Binary BX Tri". The Astrophysical Journal. 871 (2): 203. arXiv:1901.06106. Bibcode:2019ApJ...871..203L. doi:10.3847/1538-4357/aafafa. ISSN 0004-637X.
- ^ Dimitrov, Dinko P.; Kjurkchieva, Diana P. (2010-06-07). "GSC 2314−0530: the shortest-period eclipsing system with dMe components". Monthly Notices of the Royal Astronomical Society. 406 (4): 2559–2568. arXiv:1005.0260. Bibcode:2010MNRAS.406.2559D. doi:10.1111/j.1365-2966.2010.16843.x. ISSN 0035-8711.
- Kazarovets, E. V.; Samus, N. N.; Durlevich, O. V.; Kireeva, N. N.; Pastukhova, E. N. (2011-01-01). "The 80th Name-List of Variable Stars. Part I - RA 0h to 6h". Information Bulletin on Variable Stars. 5969: 1. Bibcode:2011IBVS.5969....1K. ISSN 0374-0676. BX Trianguli's database entry at VizieR.
- ^ Perdelwitz, V.; Czesla, S.; Robrade, J.; Pribulla, T.; Schmitt, J. H. M. M. (November 2018). "X-ray and UV emission of the ultrashort-period, low-mass eclipsing binary system BX Trianguli". Astronomy & Astrophysics. 619: A138. arXiv:1809.00971. Bibcode:2018A&A...619A.138P. doi:10.1051/0004-6361/201834116. ISSN 0004-6361.
- ^ "AAVSO 113th Annual Meeting Abstracts | aavso". www.aavso.org. Retrieved 2024-12-09.