LkCa 15

Last updated
LkCa 15
LkCa 15 disk protoplanetare Scheibe cropped.jpg
LkCa 15 protoplanetary disk
Observation data
Epoch J2000.0        Equinox J2000.0
Constellation Taurus
Right ascension 04h 39m 17.796s [1]
Declination +22° 21′ 03.48″ [1]
Apparent magnitude  (V)+11.91 [2]
Characteristics
Spectral type K5V [2]
Variable type T Tauri [1]
Astrometry
Proper motion (μ)RA: 10.572 [3]   mas/yr
Dec.: -17.527 [3]   mas/yr
Parallax (π)6.3619 ± 0.0264  mas [3]
Distance 513 ± 2  ly
(157.2 ± 0.7  pc)
Details
Mass 0.97 ± 0.03 [2]   M☉
Radius 1.2 [4]   R☉
Luminosity 1.22 [5]   L☉
Temperature 4730 [4]   K
Age 2 [2]   Myr
Other designations
V1079 Tau, GSC 01278-00193, TYC 1278-193-1, 2MASS J04391779+2221034 [1]
Database references
SIMBAD data
A light curve for V1079 Tauri, adapted from Alencar et al. (2018) V1079TauLightCurve.png
A light curve for V1079 Tauri, adapted from Alencar et al. (2018)

LkCa 15 is a T Tauri star in the Taurus Molecular Cloud. These types of stars are relatively young pre-main-sequence stars that show irregular variations in brightness. [7] It has a mass that is about 97% of the Sun, [2] an effective temperature of 4370 K, [5] and is slightly cooler than the Sun. Its apparent magnitude is 11.91, [2] meaning it is not visible to the naked eye.

Planetary system

LkCa 15 is surrounded by a protoplanetary disk, typical of many T Tauri stars. [7] The disk around the star is about 55 times more massive than Jupiter, [8] and consists of three major belts (components). [4] Small changes in the observed brightness of the disk may be due to a planetary companion; the star was believed to have a protoplanetary object or exoplanet orbiting it, known as LkCa 15 b [9] [10] This name stems from an older survey. [11] Later, the existence of up to three planets was suspected. The planets' existence was refuted in 2019 as higher resolution imaging became available. [4]

The LkCa 15 planetary system
Companion
(in order from star)		 Mass Semimajor axis
(AU)		 Orbital period
(days)		 Eccentricity Inclination Radius
Protoplanetary disk component 10.12–3 [4] AU 50 [4] ° —
b(unconfirmed)6±1 MJ 15.7±2.140000———
Protoplanetary disk component 220–40 [4] AU 51.5 [4] ° —
Protoplanetary disk component 355–160 [4] AU 50 [4] ° —

LkCa 15 b is a candidate protoplanetary object in orbit around LkCa 15, a star in the Taurus-Auriga Star Forming Region. Its potential discovery was effected by direct imaging techniques using the Keck II telescope in 2011 by Adam Kraus and Michael Ireland. [9] A 2015 study of observations from the Magellan Telescopes and the Large Binocular Telescope argued that the planet is forming through accretion. [10] It would be the first observed exoplanet seen in the process of active accretion. [12] The planet’s existence was refuted in 2019 as higher resolution imaging became available. [4]

Related Research Articles

<span class="mw-page-title-main">Protoplanet</span> Large planetary embryo

A protoplanet is a large planetary embryo that originated within a protoplanetary disk and has undergone internal melting to produce a differentiated interior. Protoplanets are thought to form out of kilometer-sized planetesimals that gravitationally perturb each other's orbits and collide, gradually coalescing into the dominant planets.

<span class="mw-page-title-main">HD 100546</span> Star in the constellation Musca

HD 100546, also known as KR Muscae, is a pre-main sequence star of spectral type B8 to A0 located 353 light-years from Earth in the southern constellation of Musca. The star is surrounded by a circumstellar disk from a distance of 0.2 to 4 AU, and again from 13 AU out to a few hundred AU, with evidence for a protoplanet forming at a distance of around 47 AU.

<span class="mw-page-title-main">SU Aurigae</span> Star in the constellation Auriga

SU Aurigae is a T Tauri-type variable star in the constellation Auriga. It is located about 500 light-years away in the Taurus-Auriga Star Forming Region. Its apparent magnitude is 9.30, which is dim enough that it cannot be seen with the unaided eye.

<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

AA Tauri is a young variable star in the equatorial constellation of Taurus, located in the Taurus-Auriga star-forming region. It is too faint to view with the naked eye, having an apparent visual magnitude that varies from 12.2 down to 16.1. The star is located approximately 439 light-years away from the Sun based on parallax, and is drifting further away with a radial velocity of +17 km/s.

<span class="mw-page-title-main">Taurus molecular cloud</span> Interstellar molecular cloud in the constellations Taurus and Auriga

The Taurus molecular cloud (TMC-1) is an interstellar molecular cloud in the constellations Taurus and Auriga. This cloud hosts a stellar nursery containing hundreds of newly formed stars. The Taurus molecular cloud is only 140 pc away from Earth, making it possibly the nearest large star formation region. It has been important in star formation studies at all wavelengths.

<span class="mw-page-title-main">AB Aurigae</span> Star in the constellation Auriga

AB Aurigae is a young Herbig Ae star in the Auriga constellation. It is located at a distance of approximately 531 light years from the Sun based on stellar parallax. This pre-main-sequence star has a stellar classification of A0Ve, matching an A-type main-sequence star with emission lines in the spectrum. It has 2.4 times the mass of the Sun and is radiating 38 times the Sun's luminosity from its photosphere at an effective temperature of 9,772 K. The radio emission from the system suggests the presence of a thermal jet originating from the star with a velocity of 300 km s−1. This is causing an estimated mass loss of 1.7×10−8 M☉ yr−1.

<span class="mw-page-title-main">HD 142527</span> Young star in the constellation of Lupus

HD 142527 is a binary star system in the constellation of Lupus. The primary star belongs to the Herbig Ae/Be star class, while the companion, discovered in 2012, is a red dwarf star or accreting protoplanet with a projected separation of less than 0.1″. The system is notable for its circumbinary protoplanetary disk and its discovery has helped refine models of planet formation. The orbit of companion is strongly inclined to the circumbinary protoplanetary disk.

<span class="mw-page-title-main">MWC 480</span> Star in the Taurus-Auriga star forming region of the constellation Auriga

MWC 480 is a single star, about 500 light-years away in the constellation of Auriga. It is located in the Taurus-Auriga Star-Forming Region. The name refers to the Mount Wilson Catalog of B and A stars with bright hydrogen lines in their spectra. With an apparent magnitude of 7.62, it is too faint to be seen with the naked eye.

<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">PDS 70</span> T Tauri-type star in the constellation Centaurus

PDS 70 is a very young T Tauri star in the constellation Centaurus. Located 370 light-years from Earth, it has a mass of 0.76 M☉ and is approximately 5.4 million years old. The star has a protoplanetary disk containing two nascent exoplanets, named PDS 70b and PDS 70c, which have been directly imaged by the European Southern Observatory's Very Large Telescope. PDS 70b was the first confirmed protoplanet to be directly imaged.

<span class="mw-page-title-main">HD 36112</span> Star in the constellation Taurus

HD 36112, also known as MWC 758, is a young Herbig Ae star located in the constellation Taurus, surrounded by irregular rings of cosmic dust. The system is about 3.5 million years old. The disk has a cavity at 50 astronomical units and two spiral arms at 30-75 au that are seen in near-infrared scattered light, but only one spiral arm is seen in ALMA images.

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

CI Tauri is a young star, about 2 million years old, located approximately 500 light years away in the constellation Taurus. It is still accreting material from a debris disk at an unsteady pace, possibly modulated by the eccentric orbital motion of the inner planet. The spectral signatures of compounds of sulfur were detected from the disk.

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

DH Tauri, also known as DH Tau, is a type M star, located 140 parsecs away. It forms a binary system with DI Tauri 15″ away, and has a substellar companion, either a brown dwarf or massive exoplanet.

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

RY Tauri is a young T Tauri star in the constellation of Taurus about 450 light years away, belonging to the Taurus Molecular Cloud. It is more massive than typical T Tauri stars, and may be an intermediate between this class and the Herbig Ae/Be star type.

<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">HK Tauri</span> Young binary star system in the constellation of Taurus

HK Tauri is a young binary star system in the constellation of Taurus about 434 light-years away, belonging to the Taurus Molecular Cloud.

<span class="mw-page-title-main">GI Tauri and GK Tauri</span> Binary star system in the constellation of Taurus

GK Tauri is a young T Tauri-type pre-main sequence star in the constellation of Taurus about 421 light years away, belonging to the Taurus Molecular Cloud.

<span class="mw-page-title-main">DL Tauri</span> Protostar system with planetary system in the constellation of Taurus

DL Tauri is a young T Tauri-type pre-main sequence stars in the constellation of Taurus about 522 light years away, belonging to the Taurus Molecular Cloud. It is partially obscured by the foreground gas cloud rich in carbon monoxide, and is still accreting mass, producing 0.14 L☉ due to release of accretion energy. The stellar spectrum shows the lines of ionized oxygen, nitrogen, sulfur and iron.

<span class="mw-page-title-main">HD 283572</span> Young star in constellation Taurus

HD 283572 is a young T Tauri-type pre-main sequence star in the constellation of Taurus about 414 light years away, belonging to the Taurus Molecular Cloud. It is a rather evolved protostar which already dispersed its birth shroud. The star emits a very high X-ray flux of 1031 ergs/s. That radiation flux associated with the magnetic activity induced a high coronal temperature of 3 kEv and regular flares. HD 283572 will eventually evolve to an A-type main-sequence star when on the main sequence. It is no longer accreting mass, and is magnetically decoupled from the remnants of the protoplanetary disk, belonging to the terminal, 3rd phase of the disk evolution.

References

  1. 1 2 3 4 "EM* LkCa 15". SIMBAD . Centre de données astronomiques de Strasbourg.
  2. 1 2 3 4 5 6 "Notes on LKCA 15 b". Extrasolar Planets Encyclopaedia . 1995. Retrieved 26 December 2016.
  3. 1 2 3 Brown, A. G. A.; et al. (Gaia collaboration) (2021). "Gaia Early Data Release 3: Summary of the contents and survey properties". Astronomy & Astrophysics . 649: A1. arXiv: 2012.01533 . Bibcode:2021A&A...649A...1G. doi: 10.1051/0004-6361/202039657 . S2CID   227254300. (Erratum:  doi:10.1051/0004-6361/202039657e). Gaia EDR3 record for this source at VizieR.
  4. 1 2 3 4 5 6 7 8 9 10 11 Currie, Thayne; et al. (2019), "No Clear, Direct Evidence for Multiple Protoplanets Orbiting Lk Ca 15: Lk Ca 15 BCD are Likely Inner Disk Signals", The Astrophysical Journal, 877 (1): L3, arXiv: 1905.04322 , Bibcode:2019ApJ...877L...3C, doi: 10.3847/2041-8213/ab1b42 , S2CID   152282903
  5. 1 2 Thalmann, C.; Mulders, G. D.; Hodapp, K.; Janson, M.; Grady, C. A.; Min, M.; De Juan Ovelar, M.; Carson, J.; Brandt, T.; Bonnefoy, M.; McElwain, M. W.; Leisenring, J.; Dominik, C.; Henning, T.; Tamura, M. (2014). "The architecture of the Lk Ca 15 transitional disk revealed by high-contrast imaging". Astronomy & Astrophysics. 566: A51. arXiv: 1402.1766 . Bibcode:2014A&A...566A..51T. doi:10.1051/0004-6361/201322915. S2CID   34485844.
  6. ↑ Alencar, S. H. P.; Bouvier, J.; Donati, J.-F.; Alecian, E.; Folsom, C. P.; Grankin, K.; Hussain, G. A. J.; Hill, C.; Cody, A.-M.; Carmona, A.; Dougados, C.; Gregory, S. G.; Herczeg, G.; Ménard, F.; Moutou, C.; Malo, L.; Takami, M.; collaboration, MaTYSSE (December 2018). "Inner disk structure of the classical T Tauri star LkCa 15". Astronomy and Astrophysics. 620: A195. arXiv: 1811.04806 . Bibcode:2018A&A...620A.195A. doi: 10.1051/0004-6361/201834263 .
  7. 1 2 "Encyclopedia of Science: T Tauri star". Archived from the original on 27 January 2021. Retrieved 17 January 2017.
  8. ↑ Andrews, Sean M.; Williams, Jonathan P. (2005). "Circumstellar Dust Disks in Taurus-Auriga: The Submillimeter Perspective". The Astrophysical Journal. 631 (2): 1134–1160. arXiv: astro-ph/0506187 . Bibcode:2005ApJ...631.1134A. doi:10.1086/432712. S2CID   17583379.
  9. 1 2 Kraus, Adam L.; Ireland, Michael J. (2012). "LkCa 15: A Young Exoplanet Caught at Formation?". The Astrophysical Journal. 745 (1): 5. arXiv: 1110.3808 . Bibcode:2012ApJ...745....5K. doi:10.1088/0004-637x/745/1/5. S2CID   73598684.
  10. 1 2 Sallum, S.; Follette, K. B.; Eisner, J. A.; Close, L. M.; Hinz, P.; Kratter, K.; Males, J.; Skemer, A.; MacIntosh, B.; Tuthill, P.; Bailey, V.; Defrère, D.; Morzinski, K.; Rodigas, T.; Spalding, E.; Vaz, A.; Weinberger, A. J. (2015). "Accreting protoplanets in the Lk Ca 15 transition disk". Nature. 527 (7578): 342–4. arXiv: 1511.07456 . Bibcode:2015Natur.527..342S. doi:10.1038/nature15761. PMID   26581290. S2CID   916170.
  11. ↑ Herbig, G. H.; Vrba, F. J.; Rydgren, A. E. (1986). "A spectroscopic survey of the Taurus-Auriga dark clouds for pre-main-sequence stars having CA II H, K emission". The Astronomical Journal. 91: 575. Bibcode:1986AJ.....91..575H. doi: 10.1086/114039 .
  12. ↑ Irene Klotz (18 November 2015). "Astronomers see planet still growing in its stellar womb". News Daily. Reuters. Archived from the original on 19 November 2015. Retrieved 20 November 2015.
This page is based on this Wikipedia article
Text is available under the CC BY-SA 4.0 license; additional terms may apply.
Images, videos and audio are available under their respective licenses.