---
title: "V729 Cyg"
url: "https://spacecatalog.org/object/hip-101341"
release: "DR1"
licence: "CC-BY-SA-4.0"
citation: "SpaceCatalog. V729 Cyg [catalogue entry]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hip-101341"
---

# V729 Cyg

V729 Cyg is an O7Iafep blue supergiant in the constellation [Cygnus](https://spacecatalog.org/constellation/cygnus), 2146 ly from Earth, shining at apparent magnitude 8.99 (V). Other catalogues list it as HIP 101341.

## At a glance

- **WHAT IT IS:** Blue supergiant
- **HOW FAR:** 2146 ly — The light arriving now left it that long ago.
- **HOW BRIGHT (V):** 8.99 — Binoculars reach it; the naked eye does not.
- **WHERE TO LOOK:** [Cygnus](https://spacecatalog.org/constellation/cygnus) — The patch of sky it sits in, as seen from Earth.

## Properties

| Quantity | Value |
| --- | --- |
| CLASS | O7Iafep blue supergiant |
| DISTANCE FROM EARTH | 2146 ly — by parallax |
| APPARENT MAGNITUDE (V) | 8.99 |
| ABSOLUTE MAGNITUDE (V) | −0.10 |
| CONSTELLATION | Cygnus |
| RIGHT ASCENSION (J2000) | 20h 32m 22.4s |
| DECLINATION (J2000) | +41° 18′ 19.0″ |

## Catalogue data

### WHAT KIND OF THING IT IS

What the object is in itself, rather than how it happens to look from here.

| Field | Value |
| --- | --- |
| Spectral type | O7Iafep |
| Luminosity | 95.5873 L☉ |
| Variability | Beta Lyrae-type eclipsing binary |
| Variability type (GCVS) | EB/D/GS |
| Variability period | 6.5977915 days |
| Reference epoch (HJD) | 2440413.7960 |

### 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.

| Field | Value |
| --- | --- |
| Colour index (B−V) | 1.408 |
| Variable magnitude, brightest | 8.88 |
| Variable magnitude, faintest | 9.15 |

### 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.

| Field | Value |
| --- | --- |
| Proper motion (RA) | −0.68 mas/yr |
| Proper motion (Dec) | −2.67 mas/yr |
| Radial velocity | 0 km/s |

### OTHER NAMES AND NUMBERS

The identifiers other catalogues file this object under, for anyone joining this data to theirs.

| Field | Value |
| --- | --- |
| Variable-star designation | V729 Cyg |
| Washington Double Star id | 20324+4118 |

### WHERE THESE FIGURES CAME FROM

Which catalogue, paper or model each of the fields above was read from, where the source named one.

| Field | Value |
| --- | --- |
| Spectral type from | SIMBAD (2011ApJS..193...24S, quality C) |

## Also known as

- HIP: HIP 101341
- Variable star: V729 Cyg

## Source

[HYG Database v4.1](https://github.com/astronexus/HYG-Database) — CC-BY-SA-4.0

The producer asks: HYG Database v4.1, Astronexus (github.com/astronexus/HYG-Database). Fields derived from it stay under CC BY-SA 4.0.

How this was made: https://spacecatalog.org/methods#source-hyg

## Cite this page

SpaceCatalog. V729 Cyg \[catalogue entry\]. Data release DR1 (2026-08-21). https://spacecatalog.org/object/hip-101341

```bibtex
@misc{spacecatalog_hip-101341,
  author       = {{SpaceCatalog}},
  title        = {{V729 Cyg}},
  howpublished = {SpaceCatalog, data release DR1 (2026-08-21)},
  year         = {2026},
  url          = {https://spacecatalog.org/object/hip-101341},
  note         = {Catalogue entry, data release DR1 (2026-08-21). Values from HYG Database v4.1.}
}
```

HYG Database v4.1 — CC-BY-SA-4.0

Acknowledgement the producer asks for: HYG Database v4.1, Astronexus (github.com/astronexus/HYG-Database). Fields derived from it stay under CC BY-SA 4.0.

The page itself, with its pictures, the sky map and the observing tools: https://spacecatalog.org/object/hip-101341