Flare star

Source: Wikipedia, the free encyclopedia.
An M-type flare star stripping away the atmosphere of its planet

A flare star is a

UV Ceti, first observed to flare in 1948. Today similar flare stars are classified as UV Ceti type variable stars (using the abbreviation UV) in variable star catalogs such as the General Catalogue of Variable Stars
.

Most flare stars are dim red dwarfs, although recent research indicates that less massive brown dwarfs might also be capable of flaring.[citation needed] The more massive RS Canum Venaticorum variables (RS CVn) are also known to flare, but it is understood that these flares are induced by a companion star in a binary system which causes the magnetic field to become tangled. Additionally, nine stars similar to the Sun had also been seen to undergo flare events[2] prior to the flood of

Kepler
observatory. It has been proposed that the mechanism for this is similar to that of the RS CVn variables in that the flares are being induced by a companion, namely an unseen Jupiter-like planet in a close orbit.[3]

Nearby flare stars

A flare star with orbiting planet (artist's impression)

Flare stars are intrinsically faint, but have been found to distances of 1,000

Swift satellite detected the strongest, hottest, and longest-lasting sequence of stellar flares ever seen from a nearby red dwarf, DG Canum Venaticorum. The initial blast from this record-setting series of explosions was as much as 10,000 times more powerful than the largest solar flare ever recorded.[5]

Proxima Centauri

Proxima Centauri, with planet c in the foreground and the Alpha Centauri binary in the background

The Sun's nearest stellar neighbor Proxima Centauri is a flare star that undergoes occasional increases in brightness because of magnetic activity.[6] The star's magnetic field is created by convection throughout the stellar body, and the resulting flare activity generates a total X-ray emission similar to that produced by the Sun.[7]

Wolf 359

The flare star

UV Ceti flare star,[9]
and has a relatively high flare rate.

Artist's interpretation of Wolf 359

The mean magnetic field has a strength of about 2.2 

kG (0.2 T), but this varies significantly on time scales as short as six hours.[10] By comparison, the magnetic field of the Sun averages 1 G (100 μT), although it can rise as high as 3 kG (0.3 T) in active sunspot regions.[11]

Barnard's Star

Size comparison between Jupiter, Barnard's star and the Sun

stellar flare, showing that Barnard's Star is a flare star.[12][13]

EV Lacertae

Artist's conception of a flare explosion on EV Lacertae

EV Lacertae is located 16.5 light-years away, and is the nearest star in its constellation. It is a young star, about 300 million years old, and has a strong magnetic field. In 2008, it produced a record-setting flare that was thousands of times more powerful than the largest observed solar flare.[14]

TVLM513-46546

brown dwarfs. Data from Arecibo Observatory at radio wavelengths determined that the star flares every 7054 s with a precision of one one-hundredth of a second.[15]

2MASS J18352154-3123385 A

The more massive member of the binary star

2MASS J1835
, an M6.5 star, has strong X-ray activity indicative of a flare star, although it has never been directly observed to flare.

Record-setting flares

The most powerful stellar flare detected, as of December 2005, may have come from the active binary

solar flares
.

See also

  • Solar flare – Eruption of electromagnetic radiation
  • Superflare – Strong explosion observed on stars
  • Variable star – Star whose brightness fluctuates, as seen from Earth

References

  1. doi:10.1086/126639
    .
  2. S2CID 10586370
    .
  3. S2CID 15709625
    .
  4. S2CID 116948759
    .
  5. ^ NASA/Goddard Space Flight Center, "NASA's Swift mission observes mega flares from nearby red dwarf star", ScienceDaily, 30 September 2014
  6. hdl:10211.3/172067
    .
  7. S2CID 118537213
    .
  8. doi:10.1086/176149
    .
  9. S2CID 122101052
    .
  10. S2CID 17926213
    .
  11. ^ "Calling Dr. Frankenstein! : Interactive Binaries Show Signs of Induced Hyperactivity". National Optical Astronomy Observatory. 7 January 2007. Archived from the original on 2019-06-22. Retrieved 2006-05-24.
  12. ^ Croswell, Ken (November 2005). "A Flare for Barnard's Star". Astronomy Magazine. Kalmbach Publishing Co. Retrieved 2006-08-10.
  13. ^ "V2500 Oph". The International Variable Star Index. Retrieved 18 November 2015.
  14. ^ "Pipsqueak Star Unleashes Monster Flare". NASA. Retrieved December 28, 2023.
  15. S2CID 119114679
    .
  16. ^ Osten, Rachel; Drake, Steve; Tueller, Jack; Cameron, Brian; "Swift Observations of Stellar Flares", Swift Team Meeting, 1 May 2007

External links

Retrieved from "https://en.wikipedia.org/w/index.php?title=Flare_star&oldid=1194015089"