HD 98800
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Crater |
| HD 98800 A | |
| Right ascension | 11h 22m 05.287s |
| Declination | −24° 46′ 39.78″ |
| Apparent magnitude (V) | 9.59 |
| HD 98800 B | |
| Right ascension | 11h 22m 05.288s |
| Declination | −24° 46′ 39.05″ |
| Apparent magnitude (V) | 10.06 (10.4 / 11.5) |
| Characteristics | |
| HD 98800 A | |
| Spectral type | K5V / ? |
| B−V color index | 1.17 / ? |
| HD 98800 B | |
| Spectral type | K7V / M1V |
| B−V color index | 1.37 / 1.41 |
| Variable type | T Tau / RS CVn? |
| Astrometry | |
| Proper motion (μ) | RA: -85.40 mas/yr Dec.: -33.10 mas/yr |
| Parallax (π) | 22.27±2.31 mas |
| Distance | approx. 150 ly (approx. 45 pc) |
| Absolute magnitude (MV) | 6.06 (Aa) 6.91±0.26 8.02±0.27 |
| Orbit | |
| Primary | HD 98800 A |
| Companion | HD 98800 B |
| Period (P) | 246±5 yr |
| Semi-major axis (a) | 1.471″ |
| Eccentricity (e) | 0.5 |
| Inclination (i) | 88.4±2° |
| Longitude of the node (Ω) | 184.8° |
| Periastron epoch (T) | 2025 |
| Argument of periastron (ω) (secondary) | 224.6° |
| Orbit | |
| Primary | HD 98800 Aa |
| Companion | HD 98800 Ab |
| Period (P) | 264.51±0.02 d |
| Semi-major axis (a) | 0.86±0.02 AU |
| Eccentricity (e) | 0.4808±0.0008 |
| Inclination (i) | 135.6±0.1° |
| Longitude of the node (Ω) | 170.2±0.1° |
| Periastron epoch (T) | MJD 48742.5±0.8 |
| Argument of periastron (ω) (primary) | 68.7±0.1° |
| Semi-amplitude (K1) (primary) | 6.7±0.2 km/s |
| Orbit | |
| Primary | HD 98800 Ba |
| Companion | HD 98800 Bb |
| Period (P) | 314.86±0.02 d |
| Semi-major axis (a) | 1.01±0.01 AU |
| Inclination (i) | 66.3±0.5° |
| Longitude of the node (Ω) | 342.7±0.4° |
| Periastron epoch (T) | MJD 48707.5±0.2 |
| Argument of periastron (ω) (primary) | 104.5±0.3° |
| Semi-amplitude (K1) (primary) | 24.0±0.3 km/s |
| Semi-amplitude (K2) (secondary) | 29.9±0.6 km/s |
| Details | |
| HD 98800 Aa | |
| Mass | 0.93±0.09 M☉ |
| Radius | 1.75 R☉ |
| Surface gravity (log g) | 4.25 cgs |
| Temperature | 4500 K |
| Rotational velocity (v sin i) | 5.0 km/s |
| Age | 7±5 Myr |
| HD 98800 Ab | |
| Mass | 0.29±0.02 M☉ |
| HD 98800 Ba | |
| Mass | 0.77±0.04 M☉ |
| Radius | 1.09±0.14 R☉ |
| Luminosity | 0.330±0.075 L☉ |
| Surface gravity (log g) | 4.21±0.12 cgs |
| Temperature | 4,200±150 K |
| Rotational velocity (v sin i) | 3.0 km/s |
| HD 98800 Bb | |
| Mass | 0.62±0.02 M☉ |
| Radius | 0.85±0.11 R☉ |
| Luminosity | 0.167±0.038 L☉ |
| Surface gravity (log g) | 4.34±0.12 cgs |
| Temperature | 4,000±150 K |
| Rotational velocity (v sin i) | 0.0 km/s |
| Other designations | |
| TV Crt, CD−24°9706, GJ 2084, HD 98800, HIP 55505, SAO 179815, ADS 8141 AB, CCDM J11221-2447AB | |
| Database references | |
| SIMBAD | HD 98800 |
| HD 98800A | |
| HD 98800B | |
| ARICNS | HD 98800A |
| HD 98800B | |
HD 98800, also catalogued as TV Crateris (TV Crt), is a quadruple star system in the constellation of Crater (the cup). Parallax measurements made by the Hipparcos spacecraft put it at a distance of about 150 light-years (45 parsecs) away. The system is located within the TW Hydrae association (TWA), and has received the designation TWA 4.
The system consists of HD 98800 A and HD 98800 B each of which contains two stars. In 2007, a debris disk was discovered orbiting HD 98800 B consisting of two rings which indicates there may be an extrasolar planet orbiting within a distance of 1.5 to 2 astronomical units.