DT Virginis

DT Virginis, also known as Ross 458, is a binary star system in the constellation of Virgo. It has an apparent visual magnitude of 9.79[4] 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.

DT Virginis

A light curve for DT Virginis. The main plot, adapted from Shakhovskaya (1969),[1] shows the intensity of a flare relative to the star's quiescent intensity. The inset plot, adapted from Kiraga (2012),[2] shows the periodic variation.
Observation data
Epoch J2000      Equinox J2000
Constellation Virgo
Right ascension 13h 00m 46.5603s[3]
Declination +12° 22′ 32.7168″[3]
Apparent magnitude (V) 9.79[4]
Characteristics
Evolutionary stage Main sequence
Spectral type M0.5 + M7.0[5]
U−B color index 1.12[4]
B−V color index 1.44[4]
Astrometry
Radial velocity (Rv)−12.52[6] km/s
Proper motion (μ) RA: −632.151±0.502[3] mas/yr
Dec.: −36.019±0.187[3] mas/yr
Parallax (π)86.8570 ± 0.1515 mas[3]
Distance37.55 ± 0.07 ly
(11.51 ± 0.02 pc)
Orbit[7]
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[7] M☉
Radius0.473±0.021 R☉[8]
0.368±0.031[9] R☉
Luminosity0.044+0.016
−0.012[9] L☉
Temperature3,484±50[8] K
Metallicity [Fe/H]0.09±0.10[9] dex
Rotation2.89 d[10]
Rotational velocity (v sin i)9.6±0.9[6] km/s
Age400–800[5] Myr
Secondary (B)
Mass0.090±0.005[7] M☉
Other designations
DT Vir, BD+13° 2618, GJ 494, HIP 63510, LHS 2665, LTT 13752, Ross 458, Wolf 462[11]
Database references
SIMBADdata
ARICNSdata

This star was mentioned as a suspected variable by M. Petit in 1957.[12] In 1960, O. J. Eggen classified it as a member of the Hyades moving group based on the system's space motion;[13] it is now considered a likely member of the Carina Near Moving Group.[8] Two flares were reported from this star in 1969 by N. I. Shakhovskaya, confirming it as a flare star.[1] It was identified as an astrometric binary in 1994 by W. D. Heintz, who found a period of 14.5 years.[7] The pair were resolved using adaptive optics in 1999.[7] Early mass estimates placed the companion near the substellar limit, and it was initially proposed as a brown dwarf[14] but is now considered late-type red dwarf.[5]

The primary member, component A, is an M-type main-sequence star with a stellar classification of M0.5.[5] It is young, magnetically very active star with a high rate of rotation[14] and strong Hα emission.[5] The star experiences star spots that cover 10–15% of the surface[4] It is smaller and less massive than the Sun. The star is radiating just 4.4%[9] of the luminosity of the Sun from its photosphere at an effective temperature of 3,484 K.[8]

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.[5]

The DT Virginis planetary system[15]
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(years)		 Eccentricity Inclination Radius
C (unconfirmed) 11.3 ± 4.5 MJ 1,168.0 — — — —

See also

References
  1. Shakhovskaya, N. I. (July 1969). "Flares of BD +13 2618". Information Bulletin on Variable Stars. 361: 1. Bibcode:1969IBVS..361....1S.
  2. Kiraga, M. (March 2012). "ASAS Photometry of ROSAT Sources. I. Periodic Variable Stars Coincident with Bright Sources from the ROSAT All Sky Survey". Acta Astronmica. 62 (1): 67–95. Retrieved 2 May 2022.
  3. Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
  4. 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: 257–262. Retrieved 2021-11-30.
  5. 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. L15.
  6. 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.
  7. 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. A164.
  8. 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.
  9. 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.
  10. 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.
  11. "DT Virginis". SIMBAD. Centre de données astronomiques de Strasbourg. Retrieved 2019-09-07.
  12. Petit, M. (October 1957). "On the International Cooperation for the Study of Flare Variable Stars". Soviet Astronomy. 1: 783. Bibcode:1957SvA.....1..783P.
  13. 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.
  14. 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.
  15. Schneider, J. "Notes for Ross 458(AB)". The Extrasolar Planets Encyclopaedia. Archived from the original on 2011-10-06.
This article is issued from Wikipedia. The text is licensed under Creative Commons - Attribution - Sharealike. Additional terms may apply for the media files.