DF Tauri

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DF Tauri
Observation data
Epoch J2000.0       Equinox J2000.0
Constellation Taurus [1]
Right ascension 04h 27m 02.793s [2]
Declination +25° 42′ 22.45″ [2]
Apparent magnitude  (V)11.96 [1] (12.62±0.40 + 13.51±0.06) [3]
Characteristics
Evolutionary stage Pre-main-sequence
Spectral type M3Ve [4]
B−V color index 1.47±0.51 [1]
Variable type T Tau [5]
Astrometry
Radial velocity (Rv)17.964±0.008 [6]  km/s
Proper motion (μ)RA: 2.207  mas/yr [2]
Dec.: −26.458  mas/yr [2]
Parallax (π)5.6672 ± 0.4998  mas [2]
Distance 580 ± 50  ly
(180 ± 20  pc)
Orbit [7]
Period (P)48.1±2.1 yr
Semi-major axis (a)97.0±3.2  mas (~14  au )
Eccentricity (e)0.196±0.024
Inclination (i)54.3±2.4°
Longitude of the node (Ω)38.4±2.5°
Periastron epoch (T)1977.7{{±}2.7}}
Argument of periastron (ω)
(secondary)		310.6±9.2°
Details [7]
Primary
Mass 0.56  M☉
Radius 1.8  R☉
Surface gravity (log g)3.7±0.2  cgs
Temperature 3,638±109 K  K
Rotational velocity (v sin i)16.4±2.1 km/s
Age 2  Myr
Secondary
Mass 0.42  M☉
Radius 1.6  R☉
Surface gravity (log g)3.9±0.2  cgs
Temperature 3,433±84 K  K
Rotational velocity (v sin i)46.2±2.8 km/s
Other designations
DF Tau, HD  283654, HIP  20777, WDS J04271+2542AB, GCRV  55076, IRAS F04239+2535 [8]
Database references
SIMBAD data

DF Tauri is a young binary star system in the constellation of Taurus, abbreviated DF Tau. It is one of the most active T Tauri stars in the star-forming region of Taurus and has been frequently studied. [9] [10] The system has a combined apparent visual magnitude of 11.96, [1] which requires a telescope to observe. Based on parallax measurements, it is located at a distance of approximately 580 light years from the Sun. The system is drifting further away with a heliocentric radial velocity of 18 km/s. [6]

Contents

Observations

Light curves for DF Tauri. The upper panel shows the short term variability as seen by TESS, and the lower panel shows the longer term variability seen in the ASAS-SN data. DFTauLightCurve.png
Light curves for DF Tauri. The upper panel shows the short term variability as seen by TESS , and the lower panel shows the longer term variability seen in the ASAS-SN data.

In a 1949 study of stars in the Taurus dark clouds, A. H. Joy found this star (identified as MHα 259–11) had its spectrum cloaked by continuous emission, but he chose not to group it with T Tauri-like stars. [13] It showed a spectrum type of dM0e, which matched a small red dwarf star with emission lines. [14] By 1961 it had been classified as a T Tauri star, being of low luminosity with a spectrum of variable emission lines and an association with a dark nebula. [15] These types of objects were later found to be young, low mass stellar objects at the pre-main-sequence stage. [10]

Observations taken between 1967 and 1975 showed a visual brightness variation of about one magnitude with changes in color due to temperature fluctuations. The variations were thought due to flares lasting 2 to 5 d with energies of about 1038 erg. Shorter flares lasting 1–2 h were observed. [16] These flares appeared to come from an opaque region near the stellar surface with an estimated temperature of about 9,000 K. [17]

On October 21, 1986, a lunar occultation of this star was observed from the Mauna Kea Observatories in Hawaii. Data from the observation showed that DF Tau consists of two components, forming a binary system. [9] Evidence for orbital motion was reported in 1995 using speckle interferometry. This provided an early estimate for an orbital period of 82±12 years. However, only 10% of the orbital motion had been observed at this point, so the early solution had a high error level. [18]

By 1993, DF Tau was known to be a very active star displaying an unusually large and highly variable veiling of its stellar absorption lines. It showed significant temperature differences in the veiling material. [10] DF Tau displayed periodic variation of its light curve, which suggests there is a hot spot. However, this is variable over time, indicating the accretion inflow is not to a specific section of the star. [19]

Measurements of absorption lines strongly indicated the presence of hot spots with temperatures over 5,000 K. These are likely caused by mass infall creating a shock wave near the stellar surface. [20] This was confirmed via ultraviolet measurements in 2001, and the mean accretion rate was measured at 3×10−9  M☉ /yr. [21] Historical light curve data indicated that the accretion rate from the primary circumstellar disk was modulated by the orbital motion of the secondary companion. [22]

Resolved components

In 2019, instruments on the Keck II were able to resolve the individual components of the system, allowing a more precise orbital solution to be computed. The two components are of nearly equal mass but with distinct circumstellar properties. The primary star, component A, shows strong indicators of accretion from a circumstellar disk, while similar data from the secondary, component B, is weak or absent. The secondary star appears to be rotating around three times as rapidly as the primary, which suggests its disk has begun to dissipate while the primary rotation is still disk-locked. The orbital period was found to be closer to 46.1±1.9 years with an orbital eccentricity of 0.233±0.038. [23]

Outflow from a jet (and counter-jet) were detected from observations taken in 1998, extending out to 60  au from the primary. The outflow is accelerated out to a radius of up to 12 au, reaching a steady velocity thereafter of at least 150 to 200 km/s. The jets are being powered by gravitational energy generated during the accretion process. [24]

In 2024, observations with the Atacama Large Millimeter Array demonstrated that the secondary component does indeed have a circumstellar disk. To reconcile the observations, it was proposed that there is a small cavity in the disk of component B with a radius of ~1 au. Infrared measurements with the JWST found the disks show a rich emission from molecules of CO, C2H2, HCN, OH, and H2. [25] The circumstellar disk around component A has an estimated radius of 3.7+0.3
−0.2  au and an inclination of 41°+13°
−7° to the plane of the sky. The dust in the disk has a mass of 1.4±0.10 times the mass of the Earth. The disk for component B has 1.17±1.11 Earth masses with a radius of 3.6+0.8
−0.6 au and an inclination of 46°±9°. Each disk appears to have been tidally truncated by its companion star. There is no evidence for a circumbinary disk. [7]

Related Research Articles

<span class="mw-page-title-main">Protoplanetary disk</span> Gas and dust surrounding a newly formed star

A protoplanetary disk is a rotating circumstellar disc of dense gas and dust surrounding a young newly formed star, a T Tauri star, or Herbig Ae/Be star. The protoplanetary disk may not be considered an accretion disk; while the two are similar, an accretion disk is hotter and spins much faster. It is also found on black holes, not stars. This process should not be confused with the accretion process thought to build up the planets themselves. Externally illuminated photo-evaporating protoplanetary disks are called proplyds.

<span class="mw-page-title-main">Zeta Tauri</span> Binary star in the constellation Taurus

Zeta Tauri is a binary star in the zodiac constellation of Taurus, the Bull. It has an apparent visual magnitude of about 3.0, which is bright enough to be seen with the naked eye. Parallax measurements place it at a distance of roughly 440 light-years from the Sun.

Kappa Tauri is a double star in the constellation Taurus, the two components κ1 Tauri and κ2 Tauri both members of the Hyades open cluster. The pair are approximately 150 light years from Earth and are separated from each other by about six light years.

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<span class="mw-page-title-main">XZ Tauri</span> Star in the constellation Taurus

XZ Tauri is a binary system approximately 460 light-years away in the constellation Taurus. The system consists of two T Tauri stars orbiting each other about 6 billion kilometers apart. The system made news in 2000 when a superflare was observed in the system.

<span class="mw-page-title-main">AA Tauri</span> Star in the constellation Taurus

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Scott Jay Kenyon is an American astrophysicist. His work has included advances in symbiotic and other types of interacting binary stars, the formation and evolution of stars, and the formation of planetary systems.

<span class="mw-page-title-main">Pulsed accretion</span>

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<span class="mw-page-title-main">Circumstellar disc</span> Accumulation of matter around a star

A circumstellar disc is a torus, pancake or ring-shaped accretion disk of matter composed of gas, dust, planetesimals, asteroids, or collision fragments in orbit around a star. Around the youngest stars, they are the reservoirs of material out of which planets may form. Around mature stars, they indicate that planetesimal formation has taken place, and around white dwarfs, they indicate that planetary material survived the whole of stellar evolution. Such a disc can manifest itself in various ways.

<span class="mw-page-title-main">LkCa 15</span> Star system in the constellation Taurus

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<span class="mw-page-title-main">GG Tauri</span> Star in the constellation Taurus

GG Tauri, often abbreviated as GG Tau, is a quintuple star system in the constellation Taurus. At a distance of about 450 light years away, it is located within the Taurus-Auriga Star Forming Region. The system comprises three stars orbiting each other in a hierarchical triple system, known as GG Tauri A, and another binary star system more distant from the central system, known as GG Tauri B.

<span class="mw-page-title-main">GW Orionis</span> Star in the constellation Orion

GW Orionis is a T Tauri type pre-main sequence hierarchical triple star system. It is associated with the Lambda Orionis star-forming region and has an extended circumtrinary protoplanetary disk.

<span class="mw-page-title-main">KH 15D</span> Binary star system in the constellation Monoceros

KH 15D, described as a winking star because of its unusual dips in brightness, is a binary T Tauri star system embedded in a circumbinary disk. It is a member of the young open cluster NGC 2264, located about 2,500 light-years (770 pc) from the Sun in the constellation of Monoceros.

<span class="mw-page-title-main">Circumplanetary disk</span> Accumulation of matter around a planet

A circumplanetary disk is a torus, pancake or ring-shaped accumulation of matter composed of gas, dust, planetesimals, asteroids or collision fragments in orbit around a planet. They are reservoirs of material out of which moons may form. Such a disk can manifest itself in various ways.

<span class="mw-page-title-main">BP Tauri</span> Star in the constellation Taurus

BP Tauri is a young T Tauri star in the constellation of Taurus about 416 light years away, belonging to the Taurus Molecular Cloud.

<span class="mw-page-title-main">GV Tauri</span> Young binary star system in the constellation of Taurus

GK Tauri is a young binary system composed of T Tauri-type pre-main sequence stars in the constellation of Taurus about 466 light years away, belonging to the Taurus Molecular Cloud.

<span class="mw-page-title-main">EX Lupi</span>

EX Lupi is a young, single T-Tauri star in the southern constellation of Lupus. An irregular variable, it is the prototype of young, low-mass eruptive stars named EXors, with EX Lupi being this object's variable star designation. At its minimal activity level, EX Lupi resembles a classical T-Tauri star of the M0 dwarf type. The low latitude of this star, at a declination of −40°, makes it difficult for northern observers to view. Based on parallax measurements, it is located at a distance of about 505 light years from the Sun. The star lies next to a gap in the Lupus cloud complex, a star forming region.

<span class="mw-page-title-main">RW Tauri</span> Eclipsing binary star in the constellation Taurus

RW Tauri is a binary star system in the equatorial constellation of Taurus. It has the designation HD 25487 in the Henry Draper Catalogue, while RW Tauri is the variable star designation. With a peak apparent visual magnitude of 8.05, it is too faint to be visible to the naked eye. The distance to this system is approximately 940 light years based on parallax measurements.

<span class="mw-page-title-main">CQ Tauri</span> Star in the constellation Taurus

CQ Tauri is a young variable star in the equatorial constellation of Taurus. It is too faint to be visible to the naked eye with an apparent visual magnitude that ranges from 8.7 to 12.25. The distance to this star is approximately 487 light years based on parallax measurements, and it is drifting further away with a radial velocity of ~23 km/s. It appears to be part of the T-association Tau 4. CQ Tauri lies close enough to the ecliptic to undergo lunar occultations.

<span class="mw-page-title-main">V773 Tauri</span> Star system in the constellation Taurus

V773 Tauri is a young, multiple star system in the central region of Taurus, an equatorial constellation. This is a T Tauri-type variable star that ranges in apparent visual magnitude from 10.59 down to 10.95, which is too faint to be viewed with the naked eye. Based on various estimates, the system is located at a distance of approximately 433 light years from the Sun. It lies near the dark cloud Lynds 1495.

References

  1. 1 2 3 4 Anderson, E.; Francis, Ch. (2012), "XHIP: An extended hipparcos compilation", Astronomy Letters, 38 (5): 331, arXiv: 1108.4971 , Bibcode:2012AstL...38..331A, doi:10.1134/S1063773712050015, S2CID   119257644.
  2. 1 2 3 4 5 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.
  3. ↑ Schaefer, G. H.; et al. (June 2014), "Orbital Motion in Pre-main Sequence Binaries", The Astronomical Journal, 147 (6), id. 157, arXiv: 1405.0225 , Bibcode:2014AJ....147..157S, doi:10.1088/0004-6256/147/6/157.
  4. ↑ Herbig, G. H. (1977), "Radial velocities and spectral types of T Tauri stars", Astrophysical Journal, 214: 747–758, Bibcode:1977ApJ...214..747H, doi: 10.1086/155304 .
  5. ↑ Samus, N. N.; et al. (2017), "General Catalogue of Variable Stars", Astronomy Reports, GCVS 5.1, 61 (1): 80–88, Bibcode:2017ARep...61...80S, doi:10.1134/S1063772917010085, S2CID   255195566.
  6. 1 2 Jönsson, Henrik; et al. (August 17, 2020), "APOGEE Data and Spectral Analysis from SDSS Data Release 16: Seven Years of Observations Including First Results from APOGEE-South", The Astronomical Journal, 160 (3), American Astronomical Society: 120, arXiv: 2007.05537 , Bibcode:2020AJ....160..120J, doi: 10.3847/1538-3881/aba592 , ISSN   0004-6256.
  7. 1 2 3 Kutra, Taylor; et al. (January 2025), "Sites of Planet Formation in Binary Systems. II. Double the Disks in DF Tau", The Astronomical Journal, 169 (1), id. 20, arXiv: 2411.05203 , Bibcode:2025AJ....169...20K, doi: 10.3847/1538-3881/ad900a .
  8. ↑ "DF Tau", SIMBAD , Centre de données astronomiques de Strasbourg , retrieved 2025-01-27.
  9. 1 2 Chen, W. P.; et al. (July 1990), "Discovery of Five Pre-Main-Sequence Binaries in Taurus", Astrophysical Journal, 357: 224, Bibcode:1990ApJ...357..224C, doi:10.1086/168908.
  10. 1 2 3 Guenther, Eike; Hessman, Frederic V. (February 1993), "The spectral variability of DR Tauri", Astronomy and Astrophysics, 268: 192–200, Bibcode:1993A&A...268..192G.
  11. ↑ MAST: Barbara A. Mikulski Archive for Space Telescopes, Space Telescope Science Institute, retrieved 29 January 2025.
  12. ↑ "ASAS-SN Variable Stars Database", ASAS-SN Variable Stars Database, ASAS-SN, retrieved 29 January 2025.
  13. ↑ Joy, Alfred H. (November 1949), "Bright-Line Stars among the Taurus Dark Clouds", Astrophysical Journal, 110: 424, Bibcode:1949ApJ...110..424J, doi:10.1086/145217.
  14. ↑ Bidelman, William P. (November 1954), "Catalogue and Bibliography of Emission-Line Stars of Types Later than B", Astrophysical Journal Supplement, 1: 175, Bibcode:1954ApJS....1..175B, doi:10.1086/190007. See p. 210.
  15. ↑ Bonsack, Walter K. (January 1961), "The Abundance of Lithium in T Tauri Stars : Further Observations", Astrophysical Journal, 133: 340, Bibcode:1961ApJ...133..340B, doi:10.1086/147034.
  16. ↑ Zajtseva, G. V.; Lyutyj, V. M. (1976), "Light variations and additional radiation in the spectrum of DF Tauri", Peremennye Zvezdy, 20: 255–265, Bibcode:1976PZ.....20..255Z.
  17. ↑ Rydgren, A. E.; et al. (July 1984), "UBVRI monitoring of five late-type pre-main-sequence stars.", Astronomical Journal, 89: 1015–1021, Bibcode:1984AJ.....89.1015R, doi:10.1086/113597.
  18. ↑ Thiebaut, E.; et al. (December 1995), "Orbital motion of DF Tauri from speckle interferometry", Astronomy and Astrophysics, 304: L17, Bibcode:1995A&A...304L..17T.
  19. ↑ Johns-Krull, Christopher M.; Basri, Gibor (January 1997), "The Spectral Variability of the T Tauri Star DF Tauri", The Astrophysical Journal, 474 (1): 433–454, Bibcode:1997ApJ...474..433J, doi:10.1086/303460.
  20. ↑ Unruh, Y. C.; et al. (April 1998), "Surface inhomogeneities and line variability on DF Tau", Monthly Notices of the Royal Astronomical Society, 295 (4): 781–798, Bibcode:1998MNRAS.295..781U, doi: 10.1046/j.1365-8711.1998.01275.x .
  21. ↑ Lamzin, S. A.; et al. (May 2001), "Analysis of HST and IUE Ultraviolet Spectra for T Tauri Stars: DF Tau", Astronomy Letters, 27 (5): 313–323, Bibcode:2001AstL...27..313L, doi:10.1134/1.1368701.
  22. ↑ Lamzin, S. A.; et al. (June 2001), "A possible dependence of DF Tauri's photometric activity on the relative orbital positions of the binary components", Astronomy and Astrophysics, 372 (3): 922–924, Bibcode:2001A&A...372..922L, doi:10.1051/0004-6361:20010564.
  23. ↑ Allen, T. S.; et al. (August 2017), "Properties of the Closest Young Binaries. I. DF Tau's Unequal Circumstellar Disk Evolution", The Astrophysical Journal, 845 (2), id. 161, Bibcode:2017ApJ...845..161A, doi: 10.3847/1538-4357/aa8094 .
  24. ↑ Uvarova, Anastasiia V.; et al. (July 2020), "Spatially Resolved Velocity Structures in Jets of DF Tau and UY Aur A", The Astronomical Journal, 160 (1), id. 39, arXiv: 2003.01179 , Bibcode:2020AJ....160...39U, doi: 10.3847/1538-3881/ab91a3 .
  25. ↑ Grant, Sierra L.; et al. (September 2024), "MINDS: A multi-instrument investigation into the molecule-rich JWST-MIRI spectrum of the DF Tau binary system", Astronomy & Astrophysics, 689, id. A85, arXiv: 2406.10217 , Bibcode:2024A&A...689A..85G, doi:10.1051/0004-6361/202450768.

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