EV Lacertae

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Star in the constellation Lacerta

title: "EV Lacertae" type: doc version: 1 created: 2026-02-28 author: "Wikipedia contributors" status: active scope: public tags: ["lacerta", "m-type-main-sequence-stars", "objects-with-variable-star-designations", "flare-stars", "ursa-major-moving-group", "hipparcos-objects", "gliese-and-gj-objects"] description: "Star in the constellation Lacerta" topic_path: "science/astronomy" source: "https://en.wikipedia.org/wiki/EV_Lacertae" license: "CC BY-SA 4.0" wikipedia_page_id: 0 wikipedia_revision_id: 0

::summary Star in the constellation Lacerta ::

| name=EV Lacertae | image=[[Image:Nasa EV Lacertae 250408.jpg|300px]] | caption=Artist's conception of a flare explosion on EV Lacertae. | epoch=J2000 | constell=Lacerta | ra= | dec= | appmag_v=10.26 | class=M3.5 | b-v=+1.36 | u-b=+0.83 | variable=Flare star | radial_v= | prop_mo_ra=–706.216 | prop_mo_dec=–458.920 | pm_footnote= | parallax=197.9573 | p_error=0.0220 | parallax_footnote= | absmag_v= | mass= | radius= | luminosity= | temperature= | metal_fe=–0.01 ± 0.17 | rotation= | rotational_velocity=4.5 | gravity= | age_myr = 300 | names= |Simbad=EV+Lac |image={{Location map|100x100|AlternativeMap=Lacerta_constellation_map.svg |alt=EV Lacertae is located in the constellation Lacerta |caption=Location of EV Lacertae in the constellation Lacerta|border=infobox|mark=Red_pog.png|width=300 |label=EV |position=top |lat=45.6 |long=38.2

EV Lacertae (EV Lac, Gliese 873, HIP 112460) is a faint red dwarf star 16.48 light-years away in the constellation Lacerta. It is the nearest star to the Sun in that region of the sky, although with an apparent magnitude of 10, it is only barely visible with binoculars. EV Lacertae is a spectral type M3.5 flare star that emits X-rays.

::figure[src="https://upload.wikimedia.org/wikipedia/commons/e/e1/EVLacLightCurve.png" caption="ultraviolet band]] [[light curve]] for EV Lacertae, adapted from Abdul-Aziz ''et al.'' (1995)"] ::

On 25 April 2008, NASA's Swift satellite picked up a record-setting flare from EV Lacertae. This flare was thousands of times more powerful than the largest observed solar flare. Because EV Lacertae is much farther from Earth than the Sun, the flare did not appear as bright as a solar flare. The flare would have been visible to the naked eye if the star had been in an observable part of the night sky at the time. It was the brightest flare ever seen from a star other than the Sun.

EV Lacertae is much younger than that of the Sun. Its age is estimated at 300 million years, and it is still spinning rapidly. The fast spin, together with its convective interior, produces a magnetic field much more powerful than that of the Sun. This strong magnetic field is believed to play a role in the star's ability to produce such bright flares.

In October 2022, another stellar flare was observed in EV Lacertae by a group of scientists led by Shun Inoue of Kyoto University, after observing the star in near-ultraviolet and white-light curves. The finding was announced and detailed on December 31, 2023, in the pre-print server arXiv.

References

| title=The M-dwarf Ultraviolet Spectroscopic Sample. I. Determining Stellar Parameters for Field Stars | last1=Pineda | first1=J. Sebastian | last2=Youngblood | first2=Allison | last3=France | first3=Kevin | display-authors=1 | journal=The Astrophysical Journal | volume=918 | issue=1 | id=40 | pages=23 | date=September 2021 | doi=10.3847/1538-4357/ac0aea | arxiv=2106.07656 | bibcode=2021ApJ...918...40P | s2cid=235435757 | doi-access=free }}

References

  1. "New large stellar flare detected from EV Lacertae".
  2. {{Cite Gaia DR3. 1934263333784036736
  3. (Sep 1995). "The X-ray view of the low-mass stars in the solar neighborhood". Astrophysical Journal.
  4. (December 1995). "Coordinated observations of the red dwarf flare star EV Lacertae in 1992". Astronomy and Astrophysics Supplement Series.
  5. Dunbar, Brian. (May 20, 2008). "Pipsqueak Star Unleashes Monster Flare". [[NASA]].
  6. "V* EV Lac -- Flare Star". [[Centre de Données astronomiques de Strasbourg]].
  7. (November 2001). "Late-type members of young stellar kinematic groups - I. Single stars". [[Monthly Notices of the Royal Astronomical Society]].
  8. Erro, B. I.. (1971). "Infrared photometry of UV CET stars". Boletin del Instituto de Tonantzintla.
  9. (July 2006). "Magnetic Fields in M Dwarfs: Rapid Magnetic Field Variability in EV Lacertae". The Astrophysical Journal.
  10. (April 2012). "Metallicity and Temperature Indicators in M Dwarf K-band Spectra: Testing New and Updated Calibrations with Observations of 133 Solar Neighborhood M Dwarfs". The Astrophysical Journal.
  11. (October 2008). "Large-scale magnetic topologies of mid M dwarfs". [[Monthly Notices of the Royal Astronomical Society]].

::callout[type=info title="Wikipedia Source"] This article was imported from Wikipedia and is available under the Creative Commons Attribution-ShareAlike 4.0 License. Content has been adapted to SurfDoc format. Original contributors can be found on the article history page. ::

lacertam-type-main-sequence-starsobjects-with-variable-star-designationsflare-starsursa-major-moving-grouphipparcos-objectsgliese-and-gj-objects