HAT-P-4

HAT-P-4 is a wide binary star consisting of a pair of G-type main-sequence stars[5] in the constellation of Boötes.[1] It is also designated BD+36°2593.

HAT-P-4

Observation data Epoch J2000      Equinox J2000
Constellation	Boötes[1]
HAT-P-4A
Right ascension	15^h 19^m 57.9205^s[2]
Declination	+36° 13′ 46.7380″[2]
Apparent magnitude (V)	11.159±0.010[3]
HAT-P-4B
Right ascension	15^h 20^m 00.0129^s[4]
Declination	+36° 12′ 18.5209″[4]
Apparent magnitude (V)	11.534±0.01[3]
Characteristics
Spectral type	G0V/G2V[5]
B−V color index	0.771
Astrometry
HAT-P-4A
Proper motion (μ)	RA: −21.661±0.035[2] mas/yr Dec.: −24.250±0.058[2] mas/yr
Parallax (π)	3.0919 ± 0.0273[2] mas
Distance	1,055 ± 9 ly (323 ± 3 pc)
HAT-P-4B
Proper motion (μ)	RA: −21.536±0.032[4] mas/yr Dec.: −24.229±0.056[4] mas/yr
Parallax (π)	3.0739 ± 0.0272[4]> mas
Distance	1,061 ± 9 ly (325 ± 3 pc)
Details
HAT-P-4A
Mass	~ 1.26 M☉
Radius	1.59 ± 0.07 R☉
Luminosity	0.41 L☉
Surface gravity (log g)	4.33±0.13[6] cgs
Temperature	6036±46[6] K
Metallicity [Fe/H]	0.277±0.007[6] dex
Rotational velocity (v sin i)	5.6 ± 0.9[7] km/s
Age	~4.2 Gyr
HAT-P-4B
Surface gravity (log g)	4.38±0.14[6] cgs
Temperature	6037±37[6] K
Metallicity [Fe/H]	0.175±0.006[6] dex
Position (relative to HAT-P-4A)[5]
Component	HAT-P-4B
Epoch of observation	1999/02/07
Angular distance	91.760±0.099″
Position angle	163.97±0.06°
Observed separation (projected)	28446 AU
Other designations
BD+36°2593, SAO 64638, AG+36° 1339, GSC 02569-01599, PPM 78511, TYC 2569-1599-1
Database references
SIMBAD	data
Extrasolar Planets Encyclopaedia	data
Data sources:
Hipparcos Catalogue, CCDM (2002), Bright Star Catalogue (5th rev. ed.)

The star exhibits an infrared excess noise of unknown origin.[8]

Planetary System

The primary star is home to the transiting extrasolar planet HAT-P-4b.[9]

The HAT-P-4A planetary system[10][11]

Companion (in order from star)	Mass	Semimajor axis (AU)	Orbital period (days)	Eccentricity	Inclination	Radius
b	0.651+0.033 −0.037 MJ	0.04449+0.00083 −0.0012	3.0565254±0.0000012	<0.0073	—	—

See also

• HATNet Project

References

1. Roman, Nancy G. (1987). "Identification of a Constellation From a Position". Publications of the Astronomical Society of the Pacific. 99 (617): 695–699. Bibcode:1987PASP...99..695R. doi:10.1086/132034. Vizier query form
2. 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.
3. Henden, A. A.; et al. (2016). "VizieR Online Data Catalog: AAVSO Photometric All Sky Survey (APASS) DR9 (Henden+, 2016)". VizieR On-line Data Catalog: II/336. Originally Published in: 2015AAS...22533616H. 2336. Bibcode:2016yCat.2336....0H. Vizier catalog entry for component A Vizier catalog entry for component B
4. 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.
5. Mugrauer, M.; Ginski, C.; Seeliger, M. (2014). "New wide stellar companions of exoplanet host stars". Monthly Notices of the Royal Astronomical Society. 439 (1): 1063–1070. Bibcode:2014MNRAS.439.1063M. doi:10.1093/mnras/stu044.
6. Saffe, C.; et al. (2017). "Signatures of rocky planet engulfment in HAT-P-4. Implications for chemical tagging studies". Astronomy and Astrophysics Letters. 604. L4. arXiv:1707.02180. Bibcode:2017A&A...604L...4S. doi:10.1051/0004-6361/201731430.
7. Torres, Guillermo; et al. (2012). "Improved Spectroscopic Parameters for Transiting Planet Hosts". The Astrophysical Journal. 757 (2). 161. arXiv:1208.1268. Bibcode:2012ApJ...757..161T. doi:10.1088/0004-637X/757/2/161.
8. EXTRASOLAR PLANET TRANSITS OBSERVED AT KITT PEAK NATIONAL OBSERVATORY, 2012, arXiv:1202.2799
9. Kovács, G.; et al. (2007). "HAT-P-4b: A Metal-rich Low-Density Transiting Hot Jupiter". The Astrophysical Journal Letters. 670 (1): L41–L44. arXiv:0710.0602. Bibcode:2007ApJ...670L..41K. doi:10.1086/524058.
10. Bonomo, A. S.; et al. (2017). "The GAPS Programme with HARPS-N at TNG. XIV. Investigating giant planet migration history via improved eccentricity and mass determination for 231 transiting planets". Astronomy and Astrophysics. 602. A107. arXiv:1704.00373. Bibcode:2017A&A...602A.107B. doi:10.1051/0004-6361/201629882.
11. Sada, Pedro V.; et al. (2012). "Extrasolar Planet Transits Observed at Kitt Peak National Observatory". Publications of the Astronomical Society of the Pacific. 124 (913): 212–229. arXiv:1202.2799. Bibcode:2012PASP..124..212S. doi:10.1086/665043.

External links

• Image HAT-P-4
• "HAT-P-4". Exoplanets. Archived from the original on 2016-03-03. Retrieved 2009-05-10.