HD 98649
HD 98649 is a G-type yellow dwarf star, classified as a G4V, that has the same mass and diameter as the Sun, but has only 86% of its luminosity. HD 98649 is about 138 light years from earth. HD 98649 is found in the Crater constellation. [2]
| Observation data Epoch J2000.0 Equinox J2000.0 | |
|---|---|
| Constellation | Crater |
| Right ascension | 11h 20m 51.769s[1] |
| Declination | –23° 13′ 02.43″[1] |
| Apparent magnitude (V) | +8.00[2] |
| Characteristics | |
| Spectral type | G4V |
| B−V color index | +0.658 ± 0.003[1] |
| Astrometry | |
| Proper motion (μ) | RA: –199.28 ± 0.57[1] mas/yr Dec.: –177.51 ± 0.48[1] mas/yr |
| Parallax (π) | 23.6832 ± 0.0489[3] mas |
| Distance | 137.7 ± 0.3 ly (42.22 ± 0.09 pc) |
| Absolute magnitude (MV) | +4.91[2] |
| Details | |
| Mass | 1 ± 0.03[2] M☉ |
| Radius | ~1[2] R☉ |
| Luminosity (bolometric) | 0.86[2] L☉ |
| Luminosity (visual, LV) | 0.83[note 1] L☉ |
| Surface gravity (log g) | 4.38 ± 0.08[2] cgs |
| Temperature | 5759 ± 35[2] K |
| Metallicity [Fe/H] | –0.02 ± 0.03[2] dex |
| Rotation | 27 ± 4.0 days[2] |
| Rotational velocity (v sin i) | 1.19[2] km/s |
| Age | 2.3 ± 2.0[2] Gyr |
| Other designations | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
| Extrasolar Planets Encyclopaedia | data |
Planetary system
From 1998 to 2012, the star was under observance from "the CORALIE echelle spectrograph at La Silla Observatory".
In 2012, a long-period, wide-orbiting planet was deduced by radial velocity. This was published in November.
The discoverers noted, "HD 98649b is in the top five of the most eccentric planetary orbit and the most eccentric planet known with a period larger than 600 days." The reason for this eccentricity is unknown. They also submit it as a "candidate for direct imaging", once it gets out to "10.4 AU at apoastron" and 250 milliarcseconds of separation relative to Earth.[2]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b | >6.8 ± 0.5 MJ | 5.6 ± 0.4 | 4951+607 −465 |
0.85 ± 0.05 | — | — |
Sun comparison
Chart compares the Sun to HD 98649.
| Identifier | J2000 Coordinates | Distance (ly) |
Stellar Class |
Temperature (K) |
Metallicity (dex) |
Age (Gyr) |
Notes | |
|---|---|---|---|---|---|---|---|---|
| Right ascension | Declination | |||||||
| Sun | — | — | 0.00 | G2V | 5,778 | +0.00 | 4.6 | [5] |
| HD 98649 [6] | 11h 20m 51.769s | –23° 13′ 02″ | 135 | G4V | 5,770 | −0.02 | 2.3 | |
References
- van Leeuwen, F. (2007). "Validation of the new Hipparcos reduction". Astronomy and Astrophysics. 474 (2): 653–664. arXiv:0708.1752. Bibcode:2007A&A...474..653V. doi:10.1051/0004-6361:20078357. S2CID 18759600.Vizier catalog entry
- Marmier, M.; et al. (2013). "The CORALIE survey for southern extrasolar planets XVII. New and updated long period and massive planets". Astronomy and Astrophysics. 551. A90. arXiv:1211.6444. Bibcode:2013A&A...551A..90M. doi:10.1051/0004-6361/201219639. S2CID 59467665.
- Brown, A. G. A.; et al. (Gaia collaboration) (August 2018). "Gaia Data Release 2: Summary of the contents and survey properties". Astronomy & Astrophysics. 616. A1. arXiv:1804.09365. Bibcode:2018A&A...616A...1G. doi:10.1051/0004-6361/201833051. Gaia DR2 record for this source at VizieR.
- "hd_98649_b".
- Williams, D.R. (2004). "Sun Fact Sheet". NASA. Retrieved 2009-06-23.
- HD 98649 at SIMBAD - Ids - Bibliography - Image.
Notes
- Taking the absolute visual magnitude of HD 98649 and the absolute visual magnitude of the Sun , the visual luminosity can be calculated by
