Barnard's Star
ILLUSTRATION FROM MEASURED TEMPERATURE · 3100 K · 0.000443 L☉ · VARIABLE, MAG 9.49–9.59 · TIMING NOT TO SCALE
OVERVIEW
] STARBarnard's Star is an in the constellation Ophiuchus, 5.948 from Earth, shining at apparent magnitude 9.54 (). Other catalogues list it as Gl 699, HIP 87937 and V2500 Oph. It was discovered in 1916.
The fastest-moving star in our sky, crossing the width of the full Moon every 180 , and the closest single star to the Sun.
- WHAT IT IS
- Red dwarf
- HOW FAR
- 5.948
- HOW BRIGHT (V)
The light arriving now left it that long ago.
A small telescope reaches it.
THE MODEL
] CATALOGUED RADIUSCALCULATED · NOT AN OBSERVATION · CATALOGUED RADIUS · MEASURED TEMPERATURE · 3100 K · 0.000443 L☉ · VARIABLE, MAG 9.49–9.59 · SPOTS OVER 17% OF IT · WITH A CORONA
Drawn from the catalogued radius and from the same properties the picture at the top of this page uses, at the distance a flight to it would stop. It is cool enough to convect at the surface, so it has a magnetic field wound by that convection, and the field is what everything else here comes from: the dark patches are places where it is strong enough to stop the heat arriving, so they are cooler rather than merely darker, and they are drawn at the fraction of the surface a star this active is measured to cover. The bright web between them is the same field swept to the edges of the larger convection cells, and the brighter patches beside the spots are that web bundled up — both of them brighter towards the limb, because what makes them bright is seeing down the wall of a magnetic tube rather than into its mouth. The fringe standing off the edge is the chromosphere, a forest of jets a few hundred kilometres wide, and the flames leaning out of it are prominences: chromospheric gas held up by the field, drawn at the height one reaches and the width one has. A flare is a second, far hotter thing radiating on top of the photosphere rather than the photosphere brightening, which is why the same flare is barely visible on a hot star and doubles a cool one. The streamers reaching out past the limb are the corona, which is a millionth of the disc's brightness and drawn far brighter than that, since at its own contrast nothing short of hiding the disc reveals it. Drag it, or use the arrow keys, to look from another direction. The stars behind are the 498,631 this catalogue holds real distances for, at their real positions and drawn from where the camera actually is — so the constellations are wrong, and that is the point. This is the sky from there, not the sky from here.
OBSERVING
] FROM WHERE YOU AREWhat it takes to see Barnard's Star for yourself. Everything in this part of the page is worked out for a real horizon, a real night and the equipment you say you have.
Say where you are, and this line says when Barnard's Star is worth going out for.
THROUGH AN EYEPIECE
] 150 MM TELESCOPE · 25 MM EYEPIECEOut of reach of binoculars; a 150 mm telescope reaches it. It will be a point of light in anything: a star is far enough away that no aperture on Earth gives it a width, and all the equipment changes is how easily you find it.
- 48×
- 1.08
- 1.25
- 13.0
- APPARENT MAGNITUDE ()
- 9.54 · within reach
APPARENT PLACE
] EQUINOX J2026.7Where a telescope has to be pointed today, which is not quite where the catalogue records the object: the coordinate grid itself has turned since the year 2000 the catalogue is referred to.
- RIGHT ASCENSION
- DECLINATION
- GRID TURNED SINCE
- 19.8
- PROPER MOTION SINCE
- 4.6
Computed for 2026-09-06 00:00 UT. Two things separate it from the catalogued position above: Barnard's Star has moved under its own proper motion, and the coordinate grid has turned under it — about fifty arcseconds a year of precession since 2000, and the small nodding of the Earth’s axis on top of that. Aberration and refraction are not included, and neither is parallax; each is under an arcminute, which is also about as well as the catalogued position is known. The same figure for any date.
VARIABILITY
] BY DRACONIS SPOTTED ROTATING VARIABLE- RANGE, AS SAMPLED
- 9.49 – 9.59
No period is published for this star, so there is no cycle to count. The catalogue records that it varies and by how much, and not how often.
The range is the spread the Hipparcos satellite measured, converted to the visual scale. It is approximate: the satellite sampled the star on a schedule of its own, and where a star spends little of its cycle at an extreme — the floor of an eclipse, most obviously — the sampling can miss it altogether. The classification is the General Catalogue of Variable Stars’s. These elements as data.
SPECTRUM
] A SPECTRUM OF ITS TYPENo survey in this catalogue has measured Barnard's Star’s own spectrum: the one that reaches deepest saturates on the brightest stars, and no spectrograph has been pointed at the whole sky. What is drawn below is the average of several real stars of the same class, M4 V. It shows what a star like this one shows, and every line named on it is a line of the type rather than a measurement of Barnard's Star.
A star gives out light at every wavelength at once. The dark gaps are atoms in the thin gas above its surface, each one removing the single colour it is able to absorb — which is how a list of ingredients is read off something nobody will ever touch.
Point at a labelled line — or an element above — to see which atom makes it and where it falls.
- HEAVY ELEMENTS The catalogued iron figure for Barnard's Star is -0.14, which puts it at about two thirds of the Sun's share of the elements heavier than helium. The figure is a logarithm: nought is the Sun, and every whole step is a factor of ten. It comes from published measurements of the star itself, not from the spectrum above — which belongs to the type.
Pickles (1998) stellar spectral flux library. M4 V — the average of several real stars of this type, not an observation of any one star. Sampled every 5 angstroms; 1,895 points rebinned onto 1,024 log-spaced display points and normalised to the median flux. Brightness is scaled to this spectrum’s own middle value, so the shape is the measurement and the height is not. The 3 lines named above are the ones that stand clear of the scatter and of the features around them; a spectrum at this sampling holds many more that it cannot separate. The samples themselves, as JSON, CSV or VOTable.
LIFE OF THIS STAR
] STAGE 2 OF 3Barnard's Star is a red dwarf on the main sequence, and it will stay there for four hundred billion years — many times longer than the universe has so far existed — before fading to a white dwarf without ever becoming a giant.
- COLLAPSING CLOUDtook about five hundred million years
- MAIN SEQUENCEabout four hundred billion years in allNOW
- WHITE DWARFlong after the universe as it is now
NOW Hydrogen fuses to helium in the core, and the outward push of that exactly balances the star's own weight. This is the long, steady stretch — nine-tenths of a star's life — and it ends when the core's hydrogen is gone.
NEXT The bare core, about the size of the Earth, held up by nothing but the resistance of its own crushed electrons. No fusion, no fuel, nothing left to do but cool.
EVERY STAGE ON THIS TRACK
- COLLAPSING CLOUDtook about five hundred million years
- A cold clump of gas and dust falls in on itself and heats as it falls. It stops being a cloud and starts being a star at the moment its core is hot enough to fuse hydrogen.
- MAIN SEQUENCEabout four hundred billion years in allNOW
- Hydrogen fuses to helium in the core, and the outward push of that exactly balances the star's own weight. This is the long, steady stretch — nine-tenths of a star's life — and it ends when the core's hydrogen is gone.
- WHITE DWARFlong after the universe as it is now
- The bare core, about the size of the Earth, held up by nothing but the resistance of its own crushed electrons. No fusion, no fuel, nothing left to do but cool.
- HOW FIRM No mass has been measured for this star. The figure above is inferred from its temperature by way of the main-sequence relation between the two, which is tight enough to be worth stating and is still an inference.
Which stage Barnard's Star is in was read from its catalogued class, its temperature and its total output at every wavelength — not from its brightness in visible light alone, which understates a cool star by a factor of several. The mass it started with is about a quarter of the Sun's mass, from its temperature, and that mass is what chooses the track. Every span of time here comes from the standard relation between a star’s mass and how long its fuel lasts, rounded to a single figure. They are orders of magnitude and none of them is a date.
CATALOG DATA
] 19 FIELDSThe raw catalogue values, as the source published them, with the error bars where one was published — sorted by what each set of figures is about rather than by the order they happened to be stored in.
WHAT KIND OF THING IT IS
What the object is in itself, rather than how it happens to look from here.
- Spectral type
- Surface temperature
- 3100
- Luminosity
- 0.000442588
- Luminosity (bolometric)
- 0.0034
- Radius
- 0.207
- Surface gravity (log g)
- Metallicity ([Fe/H])
- ±0.01
- Variability
- BY Draconis spotted rotating variable
- Variability type ()
- BY
HOW BRIGHT IT IS
What the light adds up to, measured through one filter at a time. A magnitude is a brightness on a backwards scale — the smaller the number, the brighter the object.
- Colour index (B−V)
- Variable magnitude, brightest
- Variable magnitude, faintest
WHERE IT IS AND HOW IT MOVES
Position, motion across the sky and the size it covers on it. These are measurements of the object as seen from here, so every one of them depends on where here is.
- Proper motion (RA)
- −801.551
- Proper motion (Dec)
- 10 362.394
- −111
OTHER NAMES AND NUMBERS
The identifiers other catalogues file this object under, for anyone joining this data to theirs.
- Variable-star designation
- V2500 Oph
WHERE THESE FIGURES CAME FROM
Which catalogue, paper or model each of the fields above was read from, where the source named one.
- Spectral type from
- SIMBAD (1991ApJS...77..417K, quality B)
- Stellar parameters from
- Gaia DR3 model fit (GSP-Phot, FLAME; RUWE ≤ 1.4)
- Metallicity from
- Median of 2 spectroscopic determinations in 4 papers, compiled from the literature (PASTEL, Soubiran+ 2016); the error bar is the scatter between them
ALSO KNOWN AS
] 4 DESIGNATIONS- Common name Barnard's Star
- Gliese Gl 699
- HIP HIP 87937
- Variable star V2500 Oph
LOOK IT UP ELSEWHERE
] 3 SERVICESEach link carries the identifier printed beside it. Nothing on this page is a measurement of our own, so a number that disagrees with one of these is worth reporting — and a service that has never catalogued this object under this name will say so plainly.
- SIMBADHIP 87937
Cross-identifications, measured values and the reference behind each of them.
- ADSobject:"HIP 87937"
Papers indexed against this object rather than against the string, newest first.
- VizieR5″ around 269.4521 +4.6934
Every published table with a row at this position, searched by coordinates rather than by name.
CITE THIS PAGE
] DR1This page is live and its numbers move when an upstream refreshes, so the citation names the release the rows belong to rather than the day you read them. The release itself is frozen, republished as a bundle, and is what a data-availability statement should point at.
SpaceCatalog. Barnard's Star [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/barnard-s-star
@misc{spacecatalog_barnard-s-star,
author = {{SpaceCatalog}},
title = {{Barnard's Star}},
howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
year = {2026},
url = {https://spacecatalog.org/object/barnard-s-star},
note = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}
}The values above were taken from HYG Database v4.1 — CC-BY-SA-4.0. Citing this page does not replace citing that catalogue, and its licence is share-alike: the terms reach whatever you build from these rows.