WISEP J121756.91+162640.2 A
ILLUSTRATION FROM MEASURED TEMPERATURE · 1000 K · LUMINOSITY CLASS
OVERVIEW
] STARWISEP J121756.91+162640.2 A is a in the constellation Coma Berenices, 32.94 from Earth.
- WHAT IT IS
- Brown dwarf
- HOW FAR
- 32.94
The light arriving now left it that long ago.
THE MODEL
] CATALOGUED RADIUSCALCULATED · NOT AN OBSERVATION · CATALOGUED RADIUS · MEASURED TEMPERATURE · 1000 K · LUMINOSITY CLASS · 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 WISEP J121756.91+162640.2 A 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 WISEP J121756.91+162640.2 A is worth going out for.
THROUGH AN EYEPIECE
] 150 MM TELESCOPE · 25 MM EYEPIECEIts brightest companion sits 0.90″ away, which at 48× is blended into one star.
- 48×
- 1.08
- 1.25
- 13.0
- 0.90 · blended into one star
A is where the pair was the year it was measured — the ones above, in 2018, and a pair in a real orbit has moved since.
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
- 21.6
- PROPER MOTION SINCE
- none published
Computed for 2026-09-07 00:00 UT. No proper motion is published for WISEP J121756.91+162640.2 A, so nothing here moves the object; what separates this from the catalogued position above is the coordinate grid turning 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.
DOUBLE STAR
] 1 PAIR| COMPONENTS | SEPARATION | POSITION ANGLE | MAGNITUDE | MEASURED |
|---|---|---|---|---|
| — | 0.9″ | 9° | 21.1 | 2018 |
Separation and position angle are as measured in the year given; a position angle is measured from north, through east. Washington Double Star Catalog 12179+1627.
CATALOG DATA
] 8 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
- 575
- Radius
- 0.091
- Mass
- 0.029
THE ORBIT
The shape of the path, where the object sits on it, and the instant those figures were true of. An orbit is a fit to observations and drifts away from the real one either side of its epoch.
- Stars in system
- 1
- Planets in system
- 1
OTHER NAMES AND NUMBERS
The identifiers other catalogues file this object under, for anyone joining this data to theirs.
- Washington Double Star id
- 12179+1627
WHERE THESE FIGURES CAME FROM
Which catalogue, paper or model each of the fields above was read from, where the source named one.
- Stellar parameters from
- NASA Exoplanet Archive composite parameters
LOOK IT UP ELSEWHERE
] 1 SERVICEEach 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.
- VizieR5″ around 184.4871 +16.4445
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. WISEP J121756.91+162640.2 A [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/wisep-j121756-91-162640-2-a
@misc{spacecatalog_wisep-j121756-91-162640-2-a,
author = {{SpaceCatalog}},
title = {{WISEP J121756.91+162640.2 A}},
howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
year = {2026},
url = {https://spacecatalog.org/object/wisep-j121756-91-162640-2-a},
note = {Catalogue entry, data release DR1 (2026-08-21). Values from NASA Exoplanet Archive (Planetary Systems Composite Parameters).}
}The values above were taken from NASA Exoplanet Archive (Planetary Systems Composite Parameters) — Public domain (NASA). Citing this page does not replace citing that catalogue.