Astronomy:HD 190007

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Short description: Star in the constellation Aquila
HD 190007
HD190007LightCurve.png
Four representative light curves for HD 190007, adapted from Burt et al. (2020)[1]
Observation data
Equinox J2000.0]] (ICRS)
Constellation Aquila[2]
Right ascension  20h 02m 47.04569s[3]
Declination +03° 19′ 34.2658″[3]
Apparent magnitude (V) 7.46[1]
Characteristics
Evolutionary stage main sequence[4]
Spectral type K5 V[5]
U−B color index +1.09[6]
B−V color index +1.11[6]
Variable type BY Dra[7]
Astrometry
Radial velocity (Rv)−30.268±0.0013[8] km/s
Proper motion (μ) RA: −90.383[3] mas/yr
Dec.: 119.430[3] mas/yr
Parallax (π)78.6465 ± 0.0198[3] mas
Distance41.47 ± 0.01 ly
(12.715 ± 0.003 pc)
Absolute magnitude (MV)6.91[2]
Details
Mass0.77±0.02[1] M☉
Radius0.80[9] R☉
Luminosity0.24[9] L☉
Surface gravity (log g)4.50[10] cgs
Temperature4,610±20[1] K
Metallicity [Fe/H]0.16[10] dex
Rotation28.626±0.046 d[1]
Other designations
V1654 Aql, BD+02°4076, GJ 775, HD 190007, HIP 98698, SAO 125379[11]
Database references
SIMBADdata
ARICNSdata

HD 190007, also known as Gliese 775, is a star with a close orbiting exoplanet in the constellation of Aquila. Parallax measurements by Gaia put the star at a distance of 41.5 light-years (12.7 parsecs) away from the Sun. It is drifting closer with a radial velocity of −30.3 km/s,[8] and is predicted to come within 11.8 light-years in 375,000 years.[12] The star has an absolute magnitude of 6.91,[2] but at its present distance the apparent visual magnitude is 7.46,[1] which is too faint to be viewed with the naked eye.

The spectrum of HD 190007 matches a K-type main-sequence star with a stellar classification of K5 V.[5] It is classified as a BY Draconis variable, showing a moderate level of magnetic activity in its chromosphere[4] with a suspected activity cycle lasting 13.7 years.[13] The star displays a mild enhancement of metals and its age is uncertain. It has 77%[1] of the mass of the Sun, 80% of the Sun's radius,[9] and is spinning with a rotation period of 28.6 days.[1] HD 190007 is radiating 24%[9] of the luminosity of the Sun from its photosphere at an effective temperature of 4,610 K.[1]

Planetary system

The exoplanet HD 190007 b on a close orbit was first detected in 2020 by the radial-velocity method.[1] Between 2015 and 2019, the Roque de los Muchachos Observatory in the Canary Islands observed HD 190007 to accumulate 37 spectrographs. This, combined with 33 spectrographs from the W. M. Keck Observatory in Hawaii over 6 years (1998 to 2014), flux measurements from the Fairborn Observatory in Arizona over 20 years, and a two-minute cadence with the Transiting Exoplanet Survey Satellite in 2022 provided the data to update the exoplanetary parameters by M. Stalport and associates in 2023.[4]

As the inclination of the orbital plane is uncertain, only a lower bound on the exoplanet mass can be determined. It has at least 15.5 times the mass of the Earth. It is orbiting close to its parent star with a moderate eccentricity and a period of just 11.7 days.

The HD 190007 planetary system[1][4]
Companion
(in order from star) 		Mass Semimajor axis
(AU) 		Orbital period
(days) 		Eccentricity Inclination Radius
b ≥15.5+1.2
−1.3 M⊕ 		0.092±0.0008 11.724128(99) 0.136+0.085
−0.080 		— —

See also

References

  1. ↑ 1.00 1.01 1.02 1.03 1.04 1.05 1.06 1.07 1.08 1.09 1.10 Burt, Jennifer et al. (2021). "A Collage of Small Planets from the Lick–Carnegie Exoplanet Survey: Exploring the Super-Earth and Sub-Neptune Mass Regime". The Astronomical Journal 161 (1): 10. doi:10.3847/1538-3881/abc2d0. Bibcode: 2021AJ....161...10B. 
  2. ↑ 2.0 2.1 2.2 Anderson, E.; Francis, Ch. (2012). "XHIP: An extended hipparcos compilation". Astronomy Letters 38 (5): 331. doi:10.1134/S1063773712050015. Bibcode: 2012AstL...38..331A. 
  3. ↑ 3.0 3.1 3.2 3.3 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.
  4. ↑ 4.0 4.1 4.2 4.3 Stalport, M. et al. (August 2023). "A review of planetary systems around HD 99492, HD 147379 and HD 190007 with HARPS-N". Astronomy & Astrophysics 678. doi:10.1051/0004-6361/202346887. A90. Bibcode: 2023A&A...678A..90S. 
  5. ↑ 5.0 5.1 Kirkpatrick, J. D. et al. (1991). "A standard stellar spectral sequence in the red/near-infrared - Classes K5 to M9". Astrophysical Journal Supplement Series 77: 417. doi:10.1086/191611. Bibcode: 1991ApJS...77..417K. 
  6. ↑ 6.0 6.1 J.-C., Mermilliod (1986). "Compilation of Eggen's UBV data, transformed to UBV (unpublished)". Catalogue of Eggen's UBV Data. Bibcode: 1986EgUBV........0M. http://cdsads.u-strasbg.fr/cgi-bin/nph-bib_query?1986EgUBV........0M&db_key=AST&nosetcookie=1. 
  7. ↑ Samus, N. N. et al. (2009). "VizieR Online Data Catalog: General Catalogue of Variable Stars (Samus+ 2007-2013)". VizieR On-line Data Catalog: B/GCVS. Originally Published in: 2009yCat....102025S 1: B/gcvs. Bibcode: 2009yCat....102025S. 
  8. ↑ 8.0 8.1 Soubiran, C. et al. (2018). "Gaia Data Release 2. The catalogue of radial velocity standard stars". Astronomy and Astrophysics 616: A7. doi:10.1051/0004-6361/201832795. Bibcode: 2018A&A...616A...7S. 
  9. ↑ 9.0 9.1 9.2 9.3 Chandler, Colin Orion et al. (2016). "The Catalog of Earth-Like Exoplanet Survey Targets (CELESTA): A Database of Habitable Zones Around Nearby Stars". The Astronomical Journal 151 (3): 59. doi:10.3847/0004-6256/151/3/59. Bibcode: 2016AJ....151...59C. 
  10. ↑ 10.0 10.1 Mishenina, T. V. et al. (2013). "Abundances of neutron-capture elements in stars of the Galactic disk substructures". Astronomy & Astrophysics 552: A128. doi:10.1051/0004-6361/201220687. Bibcode: 2013A&A...552A.128M. 
  11. ↑ "HD 190007". SIMBAD. Centre de données astronomiques de Strasbourg. http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD+190007. 
  12. ↑ Bailer-Jones, C.A.L. et al. (2018). "New stellar encounters discovered in the second Gaia data release". Astronomy & Astrophysics 616: A37. doi:10.1051/0004-6361/201833456. Bibcode: 2018A&A...616A..37B. 
  13. ↑ Obridko, V. N. et al. (October 2022). "Solar and stellar activity cycles - no synchronization with exoplanets". Monthly Notices of the Royal Astronomical Society 516 (1): 1251–1255. doi:10.1093/mnras/stac2286. Bibcode: 2022MNRAS.516.1251O. 

External links



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