HD 715
ILLUSTRATION FROM MEASURED TEMPERATURE · 6070 K
OVERVIEW
] STARHD 715 is an F8 IV yellow-white star in the constellation Pisces, 545.5 from Earth, shining at apparent magnitude 8.70 ().
- WHAT IT IS
- IV yellow-white star
- HOW FAR
- 545.5
- HOW BRIGHT (V)
The light arriving now left it that long ago.
Binoculars reach it; the naked eye does not.
THE MODEL
] CATALOGUED RADIUSCALCULATED · NOT AN OBSERVATION · CATALOGUED RADIUS · MEASURED TEMPERATURE · 6070 K · SPOTS OVER 0.021% 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 HD 715 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 HD 715 is worth going out for.
THROUGH AN EYEPIECE
] 150 MM TELESCOPE · 25 MM EYEPIECEToo faint for your eyes alone. Binoculars reach 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 ()
- 8.70 · 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
- 22.5
- PROPER MOTION SINCE
- none published
Computed for 2026-09-22 00:00 UT. No proper motion is published for HD 715, 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. The catalogue it came from publishes no error for that position, so nothing here says how far this arithmetic can be trusted — the digits above are as precise as the place they were computed from, and no more. Aberration, parallax and refraction are left out. Aberration swings every position by up to twenty arcseconds over a year; parallax stays under an arcsecond for all but the nearest stars; refraction is nothing overhead and about half a degree at the horizon, where it answers to the air, not the sky. The same figure for any date.
SPECTRUM
] A SPECTRUM OF ITS TYPENo survey in this catalogue has measured HD 715’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, F8 IV. 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 HD 715.
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.
Pickles (1998) stellar spectral flux library. F8 IV — 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 10 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 5HD 715 is a subgiant: it has used up the hydrogen in its core, it has begun to swell and cool, and it is on its way off the main sequence. In about three hundred million years it will become a red giant, and end as a white dwarf.
- COLLAPSING CLOUDtook about twenty million years
- MAIN SEQUENCEat the end of itNOW
- RED GIANTabout three hundred million years of it, when it comes
- PLANETARY NEBULAgone in about twenty thousand years
- WHITE DWARFcooling from then on
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. This star is at the very end of that: its spectrum is classed as a subgiant, which is what a star is called in the short crossing between running out of core hydrogen and swelling into a giant.
NEXT 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.
EVERY STAGE ON THIS TRACK
- COLLAPSING CLOUDtook about twenty 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 SEQUENCEat the end of itNOW
- 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 GIANTabout three hundred million years of it, when it comes
- 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 NEBULAgone in about twenty thousand years
- 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 from then on
- 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 A subgiant is the hardest kind of star to place. It is between two stages rather than in one of them, it is the shortest stretch of a star's life, and the mass it started with is what decides how long the crossing takes — so the timing above is the least firm figure in this section.
Which stage HD 715 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 half again the Sun's mass, from a published model fit, 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
] 7 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
- 6070
- Radius
- 2.5
- Mass
- 1.6
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
- 2
- Planets in system
- 1
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
] 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.
- SIMBADHD 715
Cross-identifications, measured values and the reference behind each of them.
- ADSobject:"HD 715"
Papers indexed against this object rather than against the string, newest first.
- VizieR5″ around 2.8927 +4.7672
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. HD 715 [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hd-715
@misc{spacecatalog_hd-715,
author = {{SpaceCatalog}},
title = {{HD 715}},
howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
year = {2026},
url = {https://spacecatalog.org/object/hd-715},
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) — No licence stated; acknowledgement requested. Citing this page does not replace citing that catalogue.
That catalogue asks for this acknowledgement: This research has made use of the NASA Exoplanet Archive, which is operated by the California Institute of Technology, under contract with the National Aeronautics and Space Administration under the Exoplanet Exploration Program. Cite Christiansen et al. (2025), Planetary Science Journal (doi:10.3847/PSJ/ade3c2), and the literature reference given with each value.