Σ 2398
Both stars are small red dwarfs, with each having around a third the Sun's mass and radius. They each display the type of variability common to flare stars, and their active surfaces are sources of X-ray emission. They are orbiting with period of about 295 years, at a separation of about 56 astronomical units with an orbital eccentricity of 0.70.
The pair has a relatively high proper motion of 2.2 arc seconds per year. The system is on an orbit through the Milky Way that has an eccentricity of 0.05, carrying them as close as 8 kpc and as far as 9 kpc from the Galactic Center. The plane of their galactic orbit carries them as far as 463−489 pc away from the galactic plane.
Planetary system
In 2016, a planet candidate on a 2.7-day orbit was proposed around Struve 2398 B, although the signal was found to be comparable with an instrumental noise floor. In 2019, two candidate planets were detected in orbit around component B using the radial velocity method, without detection of the previous candidate.
Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
---|---|---|---|---|---|---|
b (unconfirmed) | ≥15.7±5.7 M🜨 | 0.261+0.022 −0.028 |
91.29+0.31 −0.24 |
0.06+0.26 −0.06 |
— | — |
c (unconfirmed) | ≥13.1+8.1 −6.4 M🜨 |
0.428+0.037 −0.045 |
192.4+2.2 −1.9 |
0.03+0.22 −0.03 |
— | — |
See also
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.
- ^ Rojas-Ayala, Bárbara; et al. (April 2012). "Metallicity and Temperature Indicators in M Dwarf K-band Spectra: Testing New and Updated Calibrations with Observations of 133 Solar Neighborhood M Dwarfs". The Astrophysical Journal. 748 (2): 93. arXiv:1112.4567. Bibcode:2012ApJ...748...93R. doi:10.1088/0004-637X/748/2/93. S2CID 41902340. See Table 3.
- ^ 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.
- ^ Mann, Andrew W.; et al. (May 2015), "How to Constrain Your M Dwarf: Measuring Effective Temperature, Bolometric Luminosity, Mass, and Radius", The Astrophysical Journal, 804 (1): 38, arXiv:1501.01635, Bibcode:2015ApJ...804...64M, doi:10.1088/0004-637X/804/1/64, S2CID 19269312, 64.
- ^ Pineda, J. Sebastian; Youngblood, Allison; France, Kevin (September 2021). "The M-dwarf Ultraviolet Spectroscopic Sample. I. Determining Stellar Parameters for Field Stars". The Astrophysical Journal. 918 (1): 23. arXiv:2106.07656. Bibcode:2021ApJ...918...40P. doi:10.3847/1538-4357/ac0aea. S2CID 235435757. 40.
- ^ Reiners, Ansgar; et al. (April 2012), "A Catalog of Rotation and Activity in Early-M Stars", The Astronomical Journal, 143 (4): 15, arXiv:1201.5774, Bibcode:2012AJ....143...93R, doi:10.1088/0004-6256/143/4/93, S2CID 118425326, 93.
- ^ Baize, P. (October 1976). "Orbital elements of eighteen visual double stars". Astronomy and Astrophysics Supplement Series. 26: 177–193. Bibcode:1976A&AS...26..177B. Listed as ADS 11632.
- ^ Pettersen, B. R. (1991), "The nearby flare stars", Società Astronomica Italiana, Memorie, 62: 217–242, Bibcode:1991MmSAI..62..217P.
- ^ Schmitt, J. H. M. M.; Fleming, T. A.; Giampapa, M. S. (September 1995). "The X-ray view of the low-mass stars in the solar neighborhood". The Astrophysical Journal. 450 (9): 392–400. Bibcode:1995ApJ...450..392S. doi:10.1086/176149.
- ^ "Struve 2398 AB". Retrieved 2010-10-22.
- ^ Allen, C.; Herrera, M. A. (1998), "The galactic orbits of nearby UV Ceti stars", Revista Mexicana de Astronomía y Astrofísica, 34: 37–46, Bibcode:1998RMxAA..34...37A.
- ^ Berdiñas, Z. M.; Amado, P. J.; Anglada-Escudé, G.; Rodríguez-López, C.; Barnes, J. (2016), "High-cadence spectroscopy of M dwarfs – I. Analysis of systematic effects in HARPS-N line profile measurements on the bright binary GJ 725A+B", Monthly Notices of the Royal Astronomical Society, 459 (4): 3551–3564, arXiv:1604.05312, doi:10.1093/mnras/stw906
- ^ Barnes, J. R.; et al. (2019-06-11), Frequency of planets orbiting M dwarfs in the Solar neighbourhood, arXiv:1906.04644v1