Astronomy:BD−07 436
| Observation data {{#ifeq:J2000|J2000.0 (ICRS)|Epoch J2000.0 Equinox J2000.0 (ICRS)| Epoch J2000 [[Astronomy:Equinox (celestial coordinates)|Equinox J2000}} | |
|---|---|
| Constellation | Cetus[1] |
| A | |
| Right ascension | 02h 28m 37.228s[2] |
| Declination | −07° 03′ 38.38″[2] |
| Apparent magnitude (V) | 10.29[3] |
| B | |
| Right ascension | 02h 28m 37.324s[4] |
| Declination | −07° 03′ 41.28″[4] |
| Apparent magnitude (V) | 13.4[3] |
| Characteristics | |
| A | |
| Evolutionary stage | main-sequence star[5] |
| Spectral type | G8V[6] |
| B | |
| Evolutionary stage | main-sequence star[5] |
| Spectral type | K5[6] |
| Astrometry | |
| A | |
| Radial velocity (Rv) | +1.44±0.17[2] km/s |
| Proper motion (μ) | RA: +93.708[2] mas/yr Dec.: −1.717[2] mas/yr |
| Parallax (π) | 9.4629 ± 0.0183[2] mas |
| Distance | 344.7 ± 0.7 ly (105.7 ± 0.2 pc) |
| B | |
| Radial velocity (Rv) | +3.22±1.63[4] km/s |
| Proper motion (μ) | RA: +94.240[4] mas/yr Dec.: −3.787[4] mas/yr |
| Parallax (π) | 9.5080 ± 0.0183[4] mas |
| Distance | 343.0 ± 0.7 ly (105.2 ± 0.2 pc) |
| Absolute magnitude (MV) | 7.2[5] |
| Orbit[6][7] | |
| Primary | BD−07 436A |
| Companion | BD−07 436B |
| Semi-major axis (a) | 3.3" (461+200−140 AU) |
| Eccentricity (e) | 0.51+0.26−0.22 |
| Inclination (i) | 77+5−7° |
| Details[8] | |
| BD−07 436A | |
| Mass | 0.903+0.066−0.059 M☉ |
| Radius | 0.910+0.025−0.023 R☉ |
| Luminosity | 0.743+0.065−0.058 L☉ |
| Surface gravity (log g) | 4.476+0.014−0.015 cgs |
| Temperature | 5617±72 K |
| Metallicity [Fe/H] | −0.10+0.10−0.11 dex |
| Rotation | 15.4±0.5[9] |
| Rotational velocity (v sin i) | 4.0±0.2 km/s |
| Age | 7.99+1.90 −1.71[10] Gyr |
| BD−07 436B | |
| Mass | 0.71±0.06[5] M☉ |
| Radius | 0.69±0.12[5] R☉ |
| Surface gravity (log g) | 4.6±0.15[5] cgs |
| Temperature | 5570±240[7] K |
| Rotational velocity (v sin i) | 2.8±0.5[5] km/s |
| Age | 7.3+4.4 −4.6[10] Gyr |
| Other designations | |
| A: TYC 4697-201-1 | |
| B: | |
| Database references | |
| SIMBAD | data |
| A | |
| B | |
BD−07 436, also known as WASP-77 since 2012,[5] is a binary star system about 344 light-years away. The BD−07 436 system's concentration of heavy elements is similar to the Sun. Its stars display moderate chromospheric activity, including x-ray flares.[6]
The primary is a G-type main-sequence star, BD−07 436A (WASP-77A). The star is rotating rapidly, being spun up by the tides raised by the giant planet WASP-77Ab on its close orbit.[9] The secondary is a K-type main-sequence star BD−07 436B orbiting at a distance of 461+200−140 AU.[7]
When calculated using spin rates, the two components appear to have different ages, with the secondary one billion years old, while the primary's age is 0.4 billion years.[5] When calculated from X-ray luminosity, the ages are radically different and even more inconsistent at 4.5 and >8.9 billion years respectively. [6] These ages may be unreliable, with the spin rates and X-ray luminosities affected by binary evolution, and ages inferred from the stars' positions in the H-R diagram are 7.99 and 7.3 billion years respectively.[10]
Planetary system
In 2012 a transiting hot Jupiter planet b was detected on a very tight, circular orbit.[5] The planet may have an extended gaseous envelope and is losing mass.[6] Its equilibrium temperature is 1715+26−25 K,[8] the nightside temperature is 1786±84 K,[12] and dayside planetary temperature is 1842+34−33 K.[13]
Water vapour was detected on the planetary dayside of WASP-77Ab, indicating C/O ratio similar to solar or even lower.[14]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| Ab | 1.667+0.068−0.064 MJ | 0.02335+0.00045−0.00043 | 1.36002854±0.00000062 | 0.0074+0.0069−0.0049 | 88.91+0.74−0.95° | 1.230+0.031−0.029 RJ |
References
- ↑ Roman, Nancy G. (1987). "Identification of a constellation from a position". Publications of the Astronomical Society of the Pacific 99 (617): 695. doi:10.1086/132034. Bibcode: 1987PASP...99..695R Constellation record for this object at VizieR.
- ↑ 2.0 2.1 2.2 2.3 2.4 2.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 3.0 3.1 Trifonov, Trifon; Tal-Or, Lev; Zechmeister, Mathias; Kaminski, Adrian; Zucker, Shay; Mazeh, Tsevi (2020). "Public HARPS radial velocity database corrected for systematic errors". Astronomy and Astrophysics 636: A74. doi:10.1051/0004-6361/201936686. Bibcode: 2020A&A...636A..74T.
- ↑ 4.0 4.1 4.2 4.3 4.4 4.5 Vallenari, A. et al. (2022). "Gaia Data Release 3. Summary of the content and survey properties". Astronomy & Astrophysics. doi:10.1051/0004-6361/202243940 Gaia DR3 record for this source at VizieR.
- ↑ 5.00 5.01 5.02 5.03 5.04 5.05 5.06 5.07 5.08 5.09 Maxted, P. F. L.; Anderson, D. R.; Collier Cameron, A.; Doyle, A. P.; Fumel, A.; Gillon, M.; Hellier, C.; Jehin, E. et al. (2012), "WASP-77 Ab: A transiting hot Jupiter planet in a wide binary system", Publications of the Astronomical Society of the Pacific 125 (923): 48–55, doi:10.1086/669231
- ↑ 6.0 6.1 6.2 6.3 6.4 6.5 Salz, M.; Schneider, P. C.; Czesla, S.; Schmitt, J. H. M. M. (2015), "High-energy irradiation and mass loss rates of hot Jupiters in the solar neighborhood", Astronomy & Astrophysics 576: A42, doi:10.1051/0004-6361/201425243, Bibcode: 2015A&A...576A..42S
- ↑ 7.0 7.1 7.2 Evans, D. F.; Southworth, J.; Smalley, B.; Jørgensen, U. G.; Dominik, M.; Andersen, M. I.; Bozza, V.; Bramich, D. M. et al. (2018), "High-resolution Imaging of Transiting Extrasolar Planetary systems (HITEP). II. Lucky Imaging results from 2015 and 2016", Astronomy & Astrophysics 610: A20, doi:10.1051/0004-6361/201731855, Bibcode: 2018A&A...610A..20E
- ↑ 8.0 8.1 8.2 Cortes-Zuleta, Pia; Rojo, Patricio; Wang, Songhu; Hinse, Tobias C.; Hoyer, Sergio; Sanhueza, Bastian; Correa-Amaro, Patricio; Albornoz, Julio (2020), "TraMoS V. Updated ephemeris and multi-epoch monitoring of the hot Jupiters WASP-18Ab, WASP-19b, and WASP-77Ab", Astronomy & Astrophysics A98: 636, doi:10.1051/0004-6361/201936279, Bibcode: 2020A&A...636A..98C
- ↑ 9.0 9.1 Gallet, F.; Gallet (2020), "TATOO: Tidal-chronology standalone tool to estimate the age of massive close-in planetary systems", Astronomy & Astrophysics 641: A38, doi:10.1051/0004-6361/202038058, Bibcode: 2020A&A...641A..38G
- ↑ 10.0 10.1 10.2 Reggiani, Henrique; Schlaufman, Kevin C.; Healy, Brian F.; Lothringer, Joshua D.; Sing, David K. (2022). "Evidence that the Hot Jupiter WASP-77 a b Formed Beyond Its Parent Protoplanetary Disk's H2O Ice Line". The Astronomical Journal 163 (4): 159. doi:10.3847/1538-3881/ac4d9f. Bibcode: 2022AJ....163..159R.
- ↑ "BD−07 436". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=BD%E2%88%9207+436.
- ↑ Garhart, Emily; Deming, Drake; Mandell, Avi; Knutson, Heather A.; Wallack, Nicole; Burrows, Adam; Fortney, Jonathan J.; Hood, Callie et al. (2020), "Statistical Characterization of Hot Jupiter Atmospheres Using Spitzer's Secondary Eclipses", The Astronomical Journal 159 (4): 137, doi:10.3847/1538-3881/ab6cff, Bibcode: 2020AJ....159..137G
- ↑ Wong, Ian; Shporer, Avi; Daylan, Tansu; Benneke, Björn; Fetherolf, Tara; Kane, Stephen R.; Ricker, George R.; Vanderspek, Roland et al. (2020), "Systematic phase curve study of known transiting systems from year one of the TESS mission", The Astronomical Journal 160 (4): 155, doi:10.3847/1538-3881/ababad, Bibcode: 2020AJ....160..155W
- ↑ Mansfield, Megan; Wiser, Lindsey; Stevenson, Kevin B.; Smith, Peter; Line, Michael R.; Bean, Jacob L.; Fortney, Jonathan J.; Parmentier, Vivien et al. (2022), "Confirmation of Water Absorption in the Thermal Emission Spectrum of the Hot Jupiter WASP-77Ab with HST/WFC3", The Astronomical Journal 163 (6): 261, doi:10.3847/1538-3881/ac658f, Bibcode: 2022AJ....163..261M
Coordinates: 
02h 28m 37.226s, −07° 03′ 38.39″
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