View source for Astronomy:VB 10

{{Short description|Very small red dwarf star in the constellation Aquila}}
{{redirect|van Biesbroeck's star|his catalogue|van Biesbroeck's star catalog}}
{{Starbox begin
| name = VB 10
}}
{{Starbox image
| image = 250px
| caption = An animation of images taken with the {{convert|200|in|m|abbr=on}} [[Astronomy:Hale Telescope|Hale Telescope]] over a period of nine years showing the [[Astronomy:Proper motion|proper motion]] of VB 10.
}}
{{Starbox observe
| epoch = J2000
| constell = [[Astronomy:Aquila (constellation)|Aquila]]<ref>{{cite constellation|VB 10}}</ref>
| ra = {{RA|19|16|57.61}}<ref name=dr3/>
| dec = {{DEC|+05|09|01.6}}<ref name=dr3/>
| appmag_v = 17.30<ref name=jenkins2009>{{cite journal |bibcode=2009ApJ...704..975J |title=Rotational Velocities for M Dwarfs |last1=Jenkins |first1=J. S. |last2=Ramsey |first2=L. W. |last3=Jones |first3=H. R. A. |last4=Pavlenko |first4=Y. |last5=Gallardo |first5=J. |last6=Barnes |first6=J. R. |last7=Pinfield |first7=D. J. |journal=The Astrophysical Journal |date=2009 |volume=704 |issue=2 |page=975 |doi=10.1088/0004-637X/704/2/975 |arxiv=0908.4092 }}</ref>
}}
{{Starbox character
| class = M8.0V<ref name=jenkins2009/>
| appmag_1_passband = B
| appmag_1 = ~19.42<ref name="SIMBAD"/>
| appmag_2_passband = R
| appmag_2 = ~15.6<ref name="SIMBAD"/>
| appmag_3_passband = J
| appmag_3 = 9.908 ±0.025<ref name="SIMBAD"/>
| appmag_4_passband = H
| appmag_4 = 9.226 ±0.026<ref name="SIMBAD"/>
| appmag_5_passband = K
| appmag_5 = 8.765 ±0.022<ref name="SIMBAD"/>
| variable = [[Astronomy:Flare star|UV]]<ref name="flare-1"/>
}}
{{Starbox astrometry
| radial_v = <!--Radial velocity (in km/sec)-->
| prop_mo_ra = −599<ref name=dr3/>
| prop_mo_dec = −1,366<ref name=dr3/>
| parallax = 168.9537
| p_error = 0.0668
| parallax_footnote = <ref name=dr3>{{Cite Gaia DR3|4293315765165489536}}</ref>
| absmag_v = 18.7<ref name="Biesbroeck"/>
}}
{{Starbox detail
| source = 
| mass = {{val|0.0881|0.0026|0.0024}}<ref name="Pineda2021">{{cite journal | 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 | 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 }}</ref>
| radius = {{val|0.1183|0.0059|0.0057}}<ref name=Pineda2021/>
| gravity = 5.5<ref name=rajpurohit2013>{{cite journal |bibcode=2013A&A...556A..15R |title=The effective temperature scale of M dwarfs |last1=Rajpurohit |first1=A. S. |last2=Reylé |first2=C. |last3=Allard |first3=F. |last4=Homeier |first4=D. |last5=Schultheis |first5=M. |last6=Bessell |first6=M. S. |last7=Robin |first7=A. C. |journal=Astronomy and Astrophysics |date=2013 |volume=556 |pages=A15 |doi=10.1051/0004-6361/201321346 |arxiv=1304.4072 }}</ref>
| luminosity_bolometric = 0.000499{{±|0.000004}}<ref name=Pineda2021/>
| luminosity_visual = 0.000003<ref name=Pineda2021/>
| temperature = {{val|2508|63|60|fmt=commas}}<ref name=Pineda2021/>
| metal = ~0<ref name="disc"/>
| rotation = 23.6 days<ref name=ribas2023>{{cite journal |bibcode=2023A&A...670A.139R |title=The CARMENES search for exoplanets around M dwarfs. Guaranteed time observations Data Release 1 (2016-2020) |last1=Ribas |first1=I. |last2=Reiners |first2=A. |last3=Zechmeister |first3=M. |last4=Caballero |first4=J. A. |last5=Morales |first5=J. C. |last6=Sabotta |first6=S. |last7=Baroch |first7=D. |last8=Amado |first8=P. J. |last9=Quirrenbach |first9=A. |last10=Abril |first10=M. |last11=Aceituno |first11=J. |last12=Anglada-Escudé |first12=G. |last13=Azzaro |first13=M. |last14=Barrado |first14=D. |last15=Béjar |first15=V. J. S. |last16=Benítez De Haro |first16=D. |last17=Bergond |first17=G. |last18=Bluhm |first18=P. |last19=Calvo Ortega |first19=R. |last20=Cardona Guillén |first20=C. |last21=Chaturvedi |first21=P. |last22=Cifuentes |first22=C. |last23=Colomé |first23=J. |last24=Cont |first24=D. |last25=Cortés-Contreras |first25=M. |last26=Czesla |first26=S. |last27=Díez-Alonso |first27=E. |last28=Dreizler |first28=S. |last29=Duque-Arribas |first29=C. |last30=Espinoza |first30=N. |journal=Astronomy and Astrophysics |date=2023 |volume=670 |doi=10.1051/0004-6361/202244879 |arxiv=2302.10528 |display-authors=1 }}</ref>
| rotational_velocity = 6.5<ref name=jenkins2009/>
| age_gyr = ~1<ref name="disc"/>
}}
{{Starbox catalog
| names =
[[Astronomy:2MASS|2MASS]]&nbsp;J19165762+0509021, [[Astronomy:Variable star|V1298&nbsp;Aquilae]], {{nowrap|Gliese 752 B}}, {{nowrap|Van Biesbroeck's Star}}
}}
{{Starbox reference
| Simbad = Gl752B
| EPE = VB+10
| NSTED = VB 10
}}
{{Starbox end}}

'''VB 10''' or '''Van Biesbroeck's star''' {{IPAc-en|v|æ|n|'|b|iː|z|b|r|ʊ|k}}<ref>Charles Earle Funk (1936) ''What's the Name, Please?: A Guide to the Correct Pronunciation of Current Prominent Names'', p.161</ref> is a small and dim [[Astronomy:Red dwarf|red dwarf]]<ref name="flare-1">{{ cite web
| url=http://www.sai.msu.su/groups/cluster/gcvs/cgi-bin/search.cgi?search=V1298+Aql
| title=V1298 Aql
| work=[[Astronomy:General Catalogue of Variable Stars|General Catalogue of Variable Stars]], [[Organization:Sternberg Astronomical Institute|Sternberg Astronomical Institute]], [[Place:Moscow|Moscow]], Russia
| access-date=2009-05-28}}</ref> located in the [[Astronomy:Constellation|constellation]] [[Astronomy:Aquila (constellation)|Aquila]]. It is part of a [[Astronomy:Binary star|binary star]] system. VB 10 is historically notable as it was the least luminous and least massive known star from its discovery in 1944, until 1982 when [[Astronomy:LHS 2924|LHS 2924]] was shown to be less luminous.<ref>{{cite news |title=Van Biesbroeck's Star |url=https://www.oxfordreference.com/display/10.1093/oi/authority.20110803115142492 |access-date=16 October 2023 |work=Oxford Reference |language=en }}</ref> Although it is relatively close to Earth, at about 19 light years, VB 10 is a dim [[Astronomy:Apparent magnitude|magnitude]] 17, making it difficult to image with amateur telescopes as it can get lost in the glare of the primary star.<ref name="SIMBAD">{{cite simbad
 | title =V* V1298 Aql
 | access-date=2009-05-28}}</ref>
VB 10 is also the primary standard for the M8V spectral class.

==History==
VB 10 was discovered in 1944 by the astronomer George van Biesbroeck using the {{convert|82|in|m|abbr=on}} [[Astronomy:Otto Struve Telescope|Otto Struve reflector telescope]] at the McDonald Observatory. He found it while surveying the telescopic field of view of the high-[[Astronomy:Proper motion|proper-motion]] [[Astronomy:Red dwarf|red dwarf]] [[Astronomy:Gliese 752|Gliese 752]] (Wolf 1055), for companions. Wolf 1055 had been catalogued 25 years earlier by German astronomer [[Biography:Max Wolf|Max Wolf]] using similar [[Astrophotography|astrophotographic]] techniques. It is designated VB 10 in the 1961 publication of [[Astronomy:Van Biesbroeck's star catalog|Van Biesbroeck's star catalog]]. Later, other astronomers began referring to it as [[Astronomy:Stars named after people|Van Biesbroeck's star]] in honor of its discoverer. Because it is so dim and so close to its much brighter [[Astronomy:Binary star|primary star]], earlier astronomical surveys missed it even though its large [[Astronomy:Parallax|parallax]] and large [[Astronomy:Proper motion|proper motion]] should have made it stand out on photographic plates taken at different times.<ref name="Biesbroeck">{{ cite journal
| title=The star of lowest known luminosity
| author=van Biesbroeck, G.
| journal=[[Astronomy:The Astronomical Journal|The Astronomical Journal]]
| pages=61–62
| date=August 1944
| doi=10.1086/105801
| bibcode=1944AJ.....51...61V
| volume=51}}</ref>

==Characteristics==
VB 10 has an extremely low luminosity with a baseline [[Astronomy:Absolute magnitude|absolute magnitude]] of nearly 19 and an apparent magnitude of 17.3 (somewhat variable), making it very difficult to see.

Mathematical formulae<ref>{{Cite web|url=http://www.1728.org/magntudj.htm|title=ADVANCED MAGNITUDE CALCULATOR|website=www.1728.org|access-date=2016-04-03}}</ref> for calculating [[Astronomy:Apparent magnitude|apparent magnitude]] show that, if VB 10 occupied the place of the Sun, it would shine on Earth's sky at a magnitude of −12.87—approximately the same magnitude of that of the [[Astronomy:Full moon|full moon]].<ref>{{Cite web|url=http://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html|title=Moon Fact Sheet|website=nssdc.gsfc.nasa.gov|access-date=2016-04-03|archive-date=2010-03-23|archive-url=https://web.archive.org/web/20100323165650/http://nssdc.gsfc.nasa.gov/planetary/factsheet/moonfact.html|url-status=dead}}</ref>

Later researchers also noted that its mass, at 0.08 solar mass ({{Solar mass|link=y}}), is right at the lower limit needed to create internal pressures and temperatures high enough to initiate [[Physics:Nuclear fusion|nuclear fusion]] and actually be a [[Astronomy:Star|star]] rather than a [[Astronomy:Brown dwarf|brown dwarf]]. At the time of its discovery it was the lowest-mass star known. The previous record holder for the lowest mass was [[Astronomy:Wolf 359|Wolf 359]] at {{Solar mass|0.09}}.<ref name="Linsky">{{cite journal
| title=Stellar Activity at the End of the Main Sequence: GHRS Observations of the M8 Ve Star VB 10
| author=Linsky
| journal=The Astrophysical Journal
| date= December 20, 1995 | volume=455
| pages=670–676
| doi=10.1086/176614
| last2=Wood
| first2=Brian E.
| last3=Brown
| first3=Alexander
| last4=Giampapa
| first4=Mark S.
| last5=Ambruster
| first5=Carol
| bibcode=1995ApJ...455..670L| hdl=2060/19970022983
| hdl-access=free
}}</ref>

VB 10 is also notable by its very large [[Astronomy:Proper motion|proper motion]], moving more than one [[Arc second|arc second]] a year through the sky as seen from Earth.<ref name="SIMBAD"/>

===Flare star===
VB 10 is a [[Astronomy:Variable star|variable star]] and is identified in the [[Astronomy:General Catalogue of Variable Stars|General Catalogue of Variable Stars]] as V1298 Aquilae. It is a UV Ceti-type variable star and is known to be subject to frequent [[Astronomy:Flare star|flare events]].<ref name="flare-1"/> Its dynamics were studied from the [[Astronomy:Hubble Space Telescope|Hubble Space Telescope]] in the mid-1990s. Although VB 10 has a normal low surface temperature of 2600 [[Kelvin|K]] it was found to produce violent flares of up to 100,000 K.<ref name="Linsky"/> This came as a surprise to astronomers. It had previously been assumed that low mass red dwarfs would have insignificant or nonexistent magnetic fields, which are necessary for the production of solar flares. The dwarfs were believed to lack the radiative zone just outside the star's core that powers the [[Engineering:Dynamo|dynamo]] of stars like the [[Astronomy:Sun|Sun]]. Nevertheless, the detection of solar flares indicates some as yet unknown process allows the solely convective cores of low mass stars to produce sufficient magnetic fields to power such outbursts.<ref>{{cite web| title = Red Dwarf Dynamo Raises Puzzle over Interiors of Lowest Mass Stars | url = http://hubblesite.org/newscenter/archive/releases/1995/03/text/| access-date = 2009-08-03| date = 1995-01-10| publisher = hubblesite|archive-url=https://web.archive.org/web/20100125212616/http://hubblesite.org/newscenter/archive/releases/1995/03/text/|archive-date=25 January 2010}}</ref>

==Binary star==
{{Main|Astronomy:Gliese 752}}
VB 10 is the [[Astronomy:Binary star|secondary star]] of a bound [[Astronomy:Binary star|binary star]] system. The primary is called Gliese 752, and hence VB 10 is also referred to as Gliese 752 B. The primary star is much larger and brighter. The two stars are separated by about 74 arc seconds (~434 AU).<ref name="Biesbroeck"/>

==Claims of a planetary system==
<!-- The redirects VB 10b and VB 10 b point to this section: if you rename it please update these redirects accordingly -->
In May 2009, astronomers from [[Organization:NASA|NASA]]'s [[Organization:Jet Propulsion Laboratory|Jet Propulsion Laboratory]], Pasadena, California, announced that they had found evidence of a planet orbiting VB 10, which they designated VB 10b. The {{convert|200|in|m|abbr=on}} [[Astronomy:Hale Telescope|Hale Telescope]] at the [[Organization:Palomar Observatory|Palomar Observatory]] was used to detect evidence of this planet using the astrometry method.<ref name="disc">{{cite journal
 |title           = An Ultracool Star's Candidate Planet
 |doi             = 10.1088/0004-637X/700/1/623
 |date            = June 2009
 |journal         = [[Astronomy:The Astrophysical Journal|The Astrophysical Journal]]
 |first1=Steven H. |last1=Pravdo |first2=Stuart B. |last2=Shaklan
 |arxiv           = 0906.0544
 |bibcode         = 2009ApJ...700..623P
 |volume          = 700
 |issue = 1
 |pages           = 623–632
 |s2cid = 119239022
}}</ref><ref name="announce">{{cite web
| title=Planet-Hunting Method Succeeds at Last
| url=http://www.nasa.gov/topics/universe/features/exoplanet-20090528.html
| work=NASA NEWS, NEWS RELEASE: 2009-090
| access-date=2009-05-28
| archive-date=2021-04-15
| archive-url=https://web.archive.org/web/20210415175136/https://www.nasa.gov/topics/universe/features/exoplanet-20090528.html
| url-status=dead
}}</ref> The new planet was claimed to have a mass 6 times that of [[Astronomy:Jupiter|Jupiter]] and an orbital period of 270 days. However, subsequent studies using [[Astronomy:Doppler spectroscopy|Doppler spectroscopy]] failed to detect the radial velocity variations that would be expected if such a planet was orbiting this small star.<ref name="bean2010">{{cite journal
|title=The Proposed Giant Planet Orbiting VB 10 Does Not Exist|author=Bean, Jacob L.|author2=Seifahrt, Andreas|author3=Hartman, Henrik|author4=Nilsson, Hampus|author5=Reiners, Ansgar|author6=Dreizler, Stefan|author7=Henry, Todd J.|author8=Wiedemann, Günter
|date=2010|journal=The Astrophysical Journal Letters|volume=711|issue=1|pages=L19–L23|doi=10.1088/2041-8205/711/1/L19|bibcode=2010ApJ...711L..19B|arxiv=0912.0003 |s2cid=122135256 }}</ref><ref>{{cite journal|title=Strong Constraints to the Putative Planet Candidate around VB 10 Using Doppler Spectroscopy|author=Anglada-Escudé, Guillem|display-authors=4|author2=Shkolnik, Evgenya L.|author3=Weinberger, Alycia J.|author4=Thompson, Ian B.|author5=Osip, David J.|author6=Debes, John H.|date=2010|journal=The Astrophysical Journal Letters|volume=711|issue=1|pages=L24–L29|doi=10.1088/2041-8205/711/1/L24|bibcode=2010ApJ...711L..24A|arxiv = 1001.0043 |s2cid=119210331}}</ref> The claimants of VB 10b note that these Doppler measurements only rule out planets more massive than 3 times the mass of Jupiter, but this limit is only half the reported best-fit mass of the planet as originally claimed.<ref>{{Cite journal |last=Sanderson |first=Katharine |date=2009-12-10 |title=Exoplanet claim bites the dust |journal=Nature |language=en |volume=462 |issue=7274 |pages=705 |doi=10.1038/462705a |pmid=20010655 |issn=0028-0836}}</ref> The claims for this planet thus fall into a long history of claimed astrometric extrasolar planet detections that were subsequently refuted.<ref name="bean2010"/>

By 2016, it was suspected that the asymmetric debris disk signal was mistaken for the long-period planet.<ref>{{citation|arxiv=1605.04908|year=2016|title=Effects of disc asymmetries on astrometric measurements|doi=10.1051/0004-6361/201628298 |last1=Kral |first1=Q. |last2=Schneider |first2=J. |last3=Kennedy |first3=G. |last4=Souami |first4=D. |journal=Astronomy & Astrophysics |volume=592 |pages=A39 |s2cid=119245922 }}</ref>

==See also==
* [[Astronomy:List of smallest stars|List of smallest stars]]
* List of stars named after people

==References==
{{reflist}}

==External links==
* {{cite web |title=A movie of the proper motion of VB 10 across the sky |url=http://www.nasa.gov/mov/352427main_C-vb10motion200905-640.mov |format=.mov file / 323 KB |access-date=28 July 2009 |archive-date=14 May 2017 |archive-url=https://web.archive.org/web/20170514122205/https://www.nasa.gov/mov/352427main_C-vb10motion200905-640.mov |url-status=dead }}

{{Sky|19|16|58|+|05|09|02|19.85}}
{{Nearest star systems|4}}
{{Stars of Aquila}}

{{DEFAULTSORT:Vb 10}}
[[Category:Aquila (constellation)]]
[[Category:M-type main-sequence stars]]
[[Category:Binary stars]]
[[Category:Flare stars]]
[[Category:Gliese and GJ objects|0752]]
[[Category:Objects with variable star designations|Aquilae, V1298]]
[[Category:Hypothetical planetary systems]]
[[Category:2MASS objects|J19165762+0509021]]

{{Sourceattribution|VB 10}}