EQ Pegasi

{{Starbox begin

| name = EQ Pegasi

}}

{{Starbox image

|image={{Location map|100x100|AlternativeMap=Pegasus_constellation_map.svg

|alt=EQ Pegasi is located in the constellation Pegasus

|caption=Location of EQ Pegasi in the constellation Pegasus|border=infobox|mark=Red_pog.png|width=300

|label=EQ

|lat=50.8

|long=28.4

}}|caption=

}}

{{Starbox observe 2s

| epoch = J2000.0

| constell = Pegasus

| component1 = EQ Pegasi A

| ra1 = {{RA|23|31|52.17385}}

| dec1 = {{DEC|+19|56|14.1304}}

| appmag_v1 = 10.38 (min)

| component2 = EQ Pegasi B

| ra2 = {{RA|23|31|52.57534}}

| dec2 = {{DEC|+19|56|14.0050}}

| appmag_v2 = 12.58 (min)

}}

{{Starbox character

| component1 = EQ Pegasi A

| type = red dwarf

| class = M4Ve

| b-v =

| u-b =

| variable = Flare star

| component2 = EQ Pegasi B

| type2 = red dwarf

| class2 = M6Ve

| b-v2 =

| u-b2 =

| variable2 = Flare star

}}

{{Starbox astrometry

| component1 = EQ Pegasi A

| radial_v = {{val|-0.21|0.82}}

| prop_mo_ra = {{val|578.009|(35)}}

| prop_mo_dec = {{val|-59.769|(23)}}

| pm_footnote =

| parallax = 159.6634

| p_error = 0.0341

| parallax_footnote =

| absmag_v =

| component2 = EQ Pegasi B

| radial_v2 =

| prop_mo_ra2 = {{val|552.349|(55)}}

| prop_mo_dec2 = {{val|20.275|(36)}}

| pm_footnote2 =

| parallax2 = 159.9085

| p_error2 = 0.0513

| parallax_footnote2 =

| absmag_v2 =

}}

{{Starbox orbit

| reference =

| period_unitless = {{convert|83664.63|±|1.98|d|yr|lk=on}}

| axis = {{val|5.05797|0.00043}}

| axis_unitless = {{val|31.635|0.033|ul=AU}}

| eccentricity = {{val|0.108047|0.000053}}

| inclination = {{val|130.065|0.010}}

| node = {{val|255.0919|0.0034}}

| periastron = {{val|2401891.34|1.19|fmt=commas}}

| periarg = {{val|307.1416|0.0045}}

}}

{{Starbox detail

| component1 = A

| mass = {{val|0.43599|0.00092}}

| radius = 0.35

| temperature = 3,585{{cite DR2|2824770686019003904}}

| luminosity = 0.019

| rotation = 1.061 days

| component2 = B

| mass2 = {{val|0.16527|0.00025}}

| radius2 = 0.25

| temperature2 = 3,309{{cite DR2|2824770686019004032}}

| luminosity2 = 0.008

| rotation2 = 0.404 days

}}

{{Starbox catalog

|names = {{Odlist| V=EQ Peg | BD=+19°5116 | GJ=896 | LFT=1799 | LTT=16919 | G=68-24 | G2=129-19 | G3=128-71 | LHS=3965 | NLTT=57135 | WDS=J23317+1956AB | HIP=116132}}{{cite simbad|title=BD+19 5116|accessdate=18 August 2017}}

| component1 = EQ Peg A

| names1 = {{Odlist| TYC=1723-23-1 | 2MASS=J23315208+1956142}}{{cite simbad|title=BD+19 5116A|accessdate=18 August 2017}}

| component2 = EQ Peg B

| names2 = {{Odlist| TYC=1723-23-2 | 2MASS=J23315244+1956138 | LFT=1800 | LTT=16920 | LHS=3966 | NLTT=57136}}{{cite simbad|title=BD+19 5116A|accessdate=18 August 2017}}

}}

{{Starbox reference

| Simbad = EQ+Peg|sn=The system

| Simbad2 = GJ+896+A|sn2=A

| Simbad3 = GJ+896+B|sn3=B

| NSTED = GJ-896

}}

EQ Pegasi (also known as Gliese 896) is a nearby binary system of two red dwarfs. Both components are flare stars, with spectral types of M4Ve and M6Ve respectively, and a current separation between the components of 5.8 arcseconds. The system is at a distance of 20.4 light-years, and is 950 million years old. The primary star is orbited by one known exoplanet.

Discovery

EQ Pegasi was first noticed to be a binary star by Carl A. Wirtanen who in the course of a systematic survey of the McCormick Observatory photographic plates for M-type dwarfs, detected a companion about two magnitudes fainter at a separation of 3.5 arcseconds.

Both components were also thought to be single-lined spectroscopic binaries, with faint companions that have not been resolved in orbits of a few years, but this is no longer thought to be the case. A 2021 study of nearby stars states that "the spectroscopic binarity classification [...] is almost certainly due to activity".

Planetary system

In 2022, a Jovian planet was discovered in orbit around the system's primary star via radio astrometry. Along with the planet around TVLM 513-46546, this is the first confirmed exoplanet discovered entirely using astrometry.

{{Orbitbox planet begin

| name = Gliese 896 A

| table_ref =

}}

{{Orbitbox planet

| exoplanet = b

| mass = {{val|2.26|0.57}}

| radius =

| semimajor = {{val|0.64282|0.00068}}

| period = {{val|284.39|1.47}}

| eccentricity = {{val|0.35|0.19}}

| inclination = {{val|69.20|25.61}}

}}

In culture

In 1998, it was the basis of a hoax, as a telecommunications company claimed it had discovered "alien" signals originating from the star.

Gallery

{{gallery|align=center|width=240

|Image:EQPegALightCurve.png|A visual band light curve for EQ Pegasi A, adapted from Norton et al. (2007)

|Image:EQPegBLightCurve.png|An ultraviolet band light curve for a flare on EQ Pegasi B, adapted from Mathioudakis et al. (2006)

}}

References

{{Reflist|refs=

{{cite journal |last1=Mathioudakis |first1=M. |last2=Bloomfield |first2=D. S. |last3=Jess |first3=D. B. |last4=Dhillon |first4=V. S. |last5=Marsh |first5=T. R. |title=The periodic variations of a white-light flare observed with ULTRACAM |journal=Astronomy and Astrophysics |date=September 2006 |volume=456 |issue=1 |pages=323–327 |doi=10.1051/0004-6361:20054752 |arxiv=astro-ph/0605196 |bibcode=2006A&A...456..323M |s2cid=8572363 |url=https://ui.adsabs.harvard.edu/abs/2006A&A...456..323M |access-date=12 February 2022}}

{{cite journal |last1=Norton |first1=A. J. |last2=Wheatley |first2=P. J. |last3=West |first3=R. G. |last4=Haswell |first4=C. A. |last5=Street |first5=R. A. |last6=Collier Cameron |first6=A. |last7=Christian |first7=D. J. |last8=Clarkson |first8=W. I. |last9=Enoch |first9=B. |last10=Gallaway |first10=M. |last11=Hellier |first11=C. |last12=Horne |first12=K. |last13=Irwin |first13=J. |last14=Kane |first14=S. R. |last15=Lister |first15=T. A. |last16=Nicholas |first16=J. P. |last17=Parley |first17=N. |last18=Pollacco |first18=D. |last19=Ryans |first19=R. |last20=Skillen |first20=I. |last21=WilsonD. M. |title=New periodic variable stars coincident with ROSAT sources discovered using SuperWASP |journal=Astronomy and Astrophysics |date=May 2007 |volume=467 |issue=2 |pages=785–905 |doi=10.1051/0004-6361:20077084 |arxiv=astro-ph/0702631 |bibcode=2007A&A...467..785N |s2cid=16358048 |url=https://ui.adsabs.harvard.edu/abs/2007A&A...467..785N |access-date=11 February 2022}}

{{Cite web|url=http://news.bbc.co.uk/2/hi/science/nature/206845.stm|title=BBC News {{!}} Sci/Tech {{!}} Alien hoax dismays scientists|website=news.bbc.co.uk|access-date=2018-09-25}}

{{cite journal | title=Constraining Stellar Coronal Mass Ejections through Multi-wavelength Analysis of the Active M Dwarf EQ Peg | last1=Crosley | first1=M. K. | last2=Osten | first2=R. A. | journal=The Astrophysical Journal | volume=856 | issue=1 | at=39 | year=2018 | arxiv=1802.03440 | bibcode=2018ApJ...856...39C | doi=10.3847/1538-4357/aaaec2 | s2cid=55448675 | doi-access=free }}

{{cite journal | title=A New dMe Double Star | last1=Wirtanen | first1=C. A. | journal=Publications of the Astronomical Society of the Pacific | volume=53 | issue=316 | pages=340 | year=1941 | bibcode=1941PASP...53..340W | doi=10.1086/125371 | doi-access=free }}

{{cite journal|bibcode=2009yCat....102025S|title=VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)|journal=VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S|volume=1|pages=B/gcvs|display-authors=etal|last1=Samus|first1=N. N.|last2=Durlevich|first2=O. V.|year=2009}}

{{cite web |url=http://www.ctio.noirlab.edu/~atokovin/stars/stars.php?cat=HIP&number=116132 |title=Multiple Star Catalog |author=Tokovinin, A. |access-date=2019-08-12 }}

{{cite journal |bibcode=2008A&A...478..507M |title=The effect of activity on stellar temperatures and radii |journal=Astronomy and Astrophysics |volume=478 |issue=2 |pages=507 |last1=Morales |first1=J. C. |last2=Ribas |first2=I. |last3=Jordi |first3=C. |year=2008 |arxiv=0711.3523 |doi=10.1051/0004-6361:20078324 |s2cid=16238033 }}

{{cite journal |last1=Delfosse |first1=X. |last2=Forveille |first2=T. |display-authors=etal |date=April 1999 |title=New neighbours. I. 13 new companions to nearby M dwarfs |journal=Astronomy and Astrophysics |volume=344 |issue= |pages=897–910 |doi= |arxiv=astro-ph/9812008 |bibcode=1999A&A...344..897D}}

{{cite journal |last1=Morin |first1=J. |last2=Donati |first2=J.-F. |display-authors=etal |date=October 2008 |title=Large-scale magnetic topologies of mid M dwarfs |journal=Monthly Notices of the Royal Astronomical Society |volume=390 |issue=2 |pages=567–581 |doi=10.1111/j.1365-2966.2008.13809.x |doi-access=free |arxiv=0808.1423 |bibcode=2008MNRAS.390..567M |s2cid=11240756}}

{{cite journal |first1=Céline |last1=Reylé |first2=Kevin |last2=Jardine |first3=Pascal |last3=Fouqué |first4=Jose A. |last4=Caballero |first5=Richard L. |last5=Smart |first6=Alessandro |last6=Sozzetti |date=30 April 2021 |title=The 10 parsec sample in the Gaia era |journal=Astronomy & Astrophysics |volume=650 |issue= |pages=A201 |doi=10.1051/0004-6361/202140985 |arxiv=2104.14972 |bibcode=2021A&A...650A.201R |s2cid=233476431}} Data available at https://gruze.org/10pc/

{{cite journal |last1=Curiel |first1=Salvador |last2=Ortiz-León |first2=Gisela N. |last3=Mioduszewski |first3=Amy J. |last4=Sanchez-Bermudez |first4=Joel |date=September 2022 |title=3D Orbital Architecture of a Dwarf Binary System and Its Planetary Companion |journal=The Astronomical Journal |volume=164 |issue=3 |pages=93 |doi=10.3847/1538-3881/ac7c66 |arxiv=2208.14553 |bibcode=2022AJ....164...93C |s2cid=251953478 |doi-access=free}}

}}

Category:Pegasus (constellation)

Category:Binary stars

Category:M-type main-sequence stars

Category:Emission-line stars

Category:Planetary systems with one confirmed planet