HIP 66578
ILLUSTRATION FROM SPECTRAL TYPE DA2.4 · 21 000 K · 0.00455 L☉ · VARIABLE, MAG 12.59–12.99 · TIMING NOT TO SCALE
OVERVIEW
] STARHIP 66578 is a in the constellation Ursa Minor, 85.18 from Earth, shining at apparent magnitude 12.79 ().
- WHAT IT IS
- White dwarf
- HOW FAR
- 85.18
- HOW BRIGHT (V)
The light arriving now left it that long ago.
A small telescope reaches it.
THE MODEL
] RADIUS FROM THE LUMINOSITY AND THE TEMPERATURECALCULATED · NOT AN OBSERVATION · RADIUS FROM THE LUMINOSITY AND THE TEMPERATURE · SPECTRAL TYPE DA2.4 · 21 000 K · 0.00455 L☉ · VARIABLE, MAG 12.59–12.99
Drawn from the radius from the luminosity and the temperature and from the same properties the picture at the top of this page uses, at the distance a flight to it would stop. 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 HIP 66578 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 HIP 66578 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 ()
- 12.79 · 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
- 8.9
- PROPER MOTION SINCE
- 10.8
Computed for 2026-08-27 00:00 UT. Two things separate it from the catalogued position above: HIP 66578 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.
LIFE OF THIS STAR
] STAGE 5 OF 5HIP 66578 is a white dwarf: the bare core of a star that has already finished, about the size of the Earth, with no fuel left to burn and nothing to do from here but cool.
- COLLAPSING CLOUD—
- MAIN SEQUENCE—
- RED GIANT—
- PLANETARY NEBULA—
- WHITE DWARFcooling, with nothing to stop itNOW
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.
EVERY STAGE ON THIS TRACK
- COLLAPSING CLOUD
- 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 SEQUENCE
- 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.
- RED GIANT
- With the core out of hydrogen, the star swells enormously and its surface cools to red. It burns helium in the core and hydrogen in a shell around it, and it loses mass from its surface the whole time.
- PLANETARY NEBULA
- The outer layers drift away and the exposed core lights them from inside. It is one of the shortest things a star does and one of the most visible — most of the glowing shells in this catalogue are this stage of some star.
- WHITE DWARFcooling, with nothing to stop itNOW
- 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 Which star this core came from is not recoverable from the core: the envelope that would have said is gone. What the white dwarf itself establishes is that the star was under the mass where a supernova becomes possible, because a heavier one would not have left one of these.
Which stage HIP 66578 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 not recoverable, and the track is the one every star that leaves a white dwarf behind was on. Every span of time here comes from the standard relation between a star’s mass and how long its fuel lasts, and is rounded to a single figure: they are orders of magnitude and none of them is a date.
CATALOG DATA
] 9 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
- Luminosity
- 0.00454988
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)
- −403.8
- Proper motion (Dec)
- −26.15
- Radial velocity
- 0
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 (2011ApJ...743..138G, quality C)
ALSO KNOWN AS
] 1 DESIGNATIONS- HIP HIP 66578
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 66578
Cross-identifications, measured values and the reference behind each of them.
- ADSobject:"HIP 66578"
Papers indexed against this object rather than against the string, newest first.
- VizieR5″ around 204.7122 +70.2854
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. HIP 66578 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hip-66578
@misc{spacecatalog_hip-66578,
author = {{SpaceCatalog}},
title = {{HIP 66578}},
howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
year = {2026},
url = {https://spacecatalog.org/object/hip-66578},
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.