Langbahn Team – Weltmeisterschaft

Ross 458

Ross 458

Image of Ross 458 with the legacy surveys. The companion is the red object marked with an crosshair in the lower right.
Observation data
Epoch J2000      Equinox J2000
Constellation Virgo
Right ascension 13h 00m 46.557s[1]
Declination +12° 22′ 32.677″[1]
Apparent magnitude (V) 9.79[2]
Characteristics
Evolutionary stage Main sequence
Spectral type M0.5 + M7.0[3]
U−B color index 1.12[2]
B−V color index 1.44[2]
Astrometry
Radial velocity (Rv)−12.33±0.32[1] km/s
Proper motion (μ) RA: −628.7±0.184 mas/yr[1]
Dec.: −33.5±0.133 mas/yr[1]
Parallax (π)86.9010 ± 0.1170 mas[1]
Distance37.53 ± 0.05 ly
(11.51 ± 0.02 pc)
Orbit[4]
Period (P)13.63±0.03 yr
Semi-major axis (a)4.93±0.01 AU
Eccentricity (e)0.245±0.001
Inclination (i)130.3±0.3°
Longitude of the node (Ω)56.25±0.17°
Periastron epoch (T)2007.67±0.02
Argument of periastron (ω)
(secondary)		157.5±0.6°
Details
Primary (A)
Mass0.553±0.007[4] M☉
Radius0.473±0.021 R☉[5]
0.368±0.031[6] R☉
Luminosity0.044+0.016
−0.012[6] L☉
Temperature3,484±50[5] K
Metallicity [Fe/H]0.09±0.10[6] dex
Rotation2.89 d[7]
Rotational velocity (v sin i)9.6±0.9[8] km/s
Age400–800[3] Myr
Secondary (B)
Mass88.918+1.836
−2.844[9] MJup
C
Mass11.7+3.6
−3[10] MJup
Radius1.1±0.05[10] RJup
Luminosity2.51×10−6[10] L☉
Surface gravity (log g)4.38+0.16
−0.17[10] cgs
Temperature682+16
−17[10] K
Other designations
DT Vir, BD+13° 2618, GJ 494, HIP 63510, LHS 2665, LTT 13752, Ross 458, Wolf 462[11]
Database references
SIMBADdata
ARICNSdata

Ross 458, also referred to as DT Virginis, is a binary star system in the constellation of Virgo. It has an apparent visual magnitude of 9.79[2] and is located at a distance of 37.6 light-years from the Sun. Both of the stars are low-mass red dwarfs with at least one of them being a flare star. This binary system has a circumbinary sub-stellar companion.

A light curve for Ross 458. The main plot, adapted from Shakhovskaya (1969),[12] shows the intensity of a flare relative to the star's quiescent intensity. The inset plot, adapted from Kiraga (2012),[13] shows the periodic variation.

This star was mentioned as a suspected variable by M. Petit in 1957.[14] In 1960, O. J. Eggen classified it as a member of the Hyades moving group based on the system's space motion;[15] it is now considered a likely member of the Carina Near Moving Group.[5] Two flares were reported from this star in 1969 by N. I. Shakhovskaya, confirming it as a flare star.[12] It was identified as an astrometric binary in 1994 by W. D. Heintz, who found a period of 14.5 years.[4] The pair were resolved using adaptive optics in 1999.[4] Early mass estimates placed the companion near the substellar limit, and it was initially proposed as a brown dwarf[16] but is now considered late-type red dwarf.[3]

The primary member, component A, is an M-type main-sequence star with a stellar classification of M0.5.[3] It is young, magnetically very active star with a high rate of rotation[16] and strong Hα emission.[3] The star experiences star spots that cover 10–15% of the surface[2] It is smaller and less massive than the Sun. The star is radiating just 4.4%[6] of the luminosity of the Sun from its photosphere at an effective temperature of 3,484 K.[5]

Planetary system

A distant sub-stellar companion to the binary star system was discovered in 2010 as part of a deep infrared sky survey. This is most likely a T8 spectral type brown dwarf with an estimated rotation period of 6.75±1.58 h. The object varies slightly in brightness, which may be due to patchy clouds.[3] The companion lacks a detectable oxygen in the atmosphere, implying its formation from sequestrated source or peculiar atmospheric chemistry.[17]

The Ross 458 planetary system[10][18]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(years) 		Eccentricity Inclination Radius
C 11.7 MJ 1,110 — — — 1.1 RJ

See also

References

  1. ^ a b c d e 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.
  2. ^ a b c d e Alekseev, I. Y.; Bondar, N. I. (1997). "Spottedness of the emission-line dwarf stars BF CVn, DT Vir, EQ Vir, and V1396 Cyg from photoelectric and photographic observations". Astronomy Letters. 23 (2): 257–262. Bibcode:1997AstL...23..257A. Retrieved 2021-11-30.
  3. ^ a b c d e f Manjavacas, Elena; et al. (April 2019). "Cloud Atlas: Rotational Spectral Modulations and Potential Sulfide Clouds in the Planetary-mass, Late T-type Companion Ross 458C". The Astrophysical Journal Letters. 875 (2): 7. arXiv:1903.10702. Bibcode:2019ApJ...875L..15M. doi:10.3847/2041-8213/ab13b9. S2CID 85518395. L15.
  4. ^ a b c d Laugier, R.; et al. (March 2019). "Recovering saturated images for high dynamic kernel-phase analysis. Application to the determination of dynamical masses for the system Gl 494AB". Astronomy & Astrophysics. 623: 8. arXiv:1901.02824. Bibcode:2019A&A...623A.164L. doi:10.1051/0004-6361/201834387. S2CID 119495214. A164.
  5. ^ a b c d Houdebine, E. R. (September 2010). "Observation and modelling of main-sequence star chromospheres - XIV. Rotation of dM1 stars". Monthly Notices of the Royal Astronomical Society. 407 (3): 1657–1673. Bibcode:2010MNRAS.407.1657H. doi:10.1111/j.1365-2966.2010.16827.x.
  6. ^ a b c d Khata, Dhrimadri; et al. (April 2020). "Understanding the physical properties of young M dwarfs: NIR spectroscopic studies". Monthly Notices of the Royal Astronomical Society. 493 (3): 4533–4550. arXiv:2002.05762. Bibcode:2020MNRAS.493.4533K. doi:10.1093/mnras/staa427.
  7. ^ Küker, M.; et al. (2019). "Cycle period, differential rotation and meridional flow for early M dwarf stars". Astronomy & Astrophysics. 622: A40. arXiv:1804.02925. Bibcode:2019A&A...622A..40K. doi:10.1051/0004-6361/201833173. S2CID 118842388.
  8. ^ Fouqué, Pascal; et al. (April 2018). "SPIRou Input Catalogue: global properties of 440 M dwarfs observed with ESPaDOnS at CFHT". Monthly Notices of the Royal Astronomical Society. 475 (2): 1960–1986. arXiv:1712.04490. Bibcode:2018MNRAS.475.1960F. doi:10.1093/mnras/stx3246.
  9. ^ Feng, Fabo; Butler, R. Paul; et al. (August 2022). "3D Selection of 167 Substellar Companions to Nearby Stars". The Astrophysical Journal Supplement Series. 262 (21): 21. arXiv:2208.12720. Bibcode:2022ApJS..262...21F. doi:10.3847/1538-4365/ac7e57. S2CID 251864022.
  10. ^ a b c d e f Zhang, Zhoujian; Liu, Michael C.; Marley, Mark S.; Line, Michael R.; Best, William M. J. (2021-07-01). "Uniform Forward-Modeling Analysis of Ultracool Dwarfs. I. Methodology and Benchmarking". The Astrophysical Journal. 916 (1): 53. arXiv:2011.12294. Bibcode:2021ApJ...916...53Z. doi:10.3847/1538-4357/abf8b2. ISSN 0004-637X.
  11. ^ "DT Virginis". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-07.
  12. ^ a b Shakhovskaya, N. I. (July 1969). "Flares of BD +13 2618". Information Bulletin on Variable Stars. 361: 1. Bibcode:1969IBVS..361....1S.
  13. ^ Kiraga, M. (March 2012). "ASAS Photometry of ROSAT Sources. I. Periodic Variable Stars Coincident with Bright Sources from the ROSAT All Sky Survey". Acta Astronomica. 62 (1): 67–95. arXiv:1204.3825. Bibcode:2012AcA....62...67K. Retrieved 2 May 2022.
  14. ^ Petit, M. (October 1957). "On the International Cooperation for the Study of Flare Variable Stars". Soviet Astronomy. 1: 783. Bibcode:1957SvA.....1..783P.
  15. ^ Eggen, Olin J. (1960). "Stellar Groups, VII. The Structure of the Hyades Group". Monthly Notices of the Royal Astronomical Society. 120 (6): 540–62. Bibcode:1960MNRAS.120..540E. doi:10.1093/mnras/120.6.540.
  16. ^ a b Beuzit, J. -L.; et al. (October 2004). "New neighbours. III. 21 new companions to nearby dwarfs, discovered with adaptive optics". Astronomy and Astrophysics. 425: 997–1008. arXiv:astro-ph/0106277. Bibcode:2004A&A...425..997B. doi:10.1051/0004-6361:20048006. S2CID 15398860.
  17. ^ Gaarn, Josefine; Burningham, Ben; Faherty, Jacqueline K.; Visscher, Channon; Marley, Mark S.; Gonzales, Eileen C.; Calamari, Emily; Bardalez Gagliuffi, Daniella; Lupu, Roxana; Freedman, Richard (2023), "The puzzle of the formation of T8 dwarf Ross 458c", Monthly Notices of the Royal Astronomical Society, 521 (4): 5761–5775, arXiv:2303.16863, doi:10.1093/mnras/stad753
  18. ^ "Ross 458 Overview". NASA Exoplanet Archive.
Quelle: https://en.wikipedia.org/wiki/Ross_458