In this article, we will address the topic of HD 17156, exploring its many facets and its relevance today. HD 17156 is a topic that has aroused interest and curiosity over time, sparks debate and opinion in various areas and has left its mark on society. Along these lines, we will analyze different perspectives on HD 17156, delving into its origins, evolution and impact on contemporary culture. From its impact on daily life to its implications in the professional field, HD 17156 is a vital topic that deserves to be explored in detail and that encourages us to reflect on its influence on our lives.
| Observation data Epoch J2000 Equinox J2000 | |
|---|---|
| Constellation | Cassiopeia[1] |
| Right ascension | 02h 49m 44.48710s[2] |
| Declination | +71° 45′ 11.6292″[2] |
| Apparent magnitude (V) | 8.16[3] |
| Characteristics | |
| Evolutionary stage | main sequence[2] |
| Spectral type | F9V[4] |
| Astrometry | |
| Radial velocity (Rv) | −3.29±0.13[2] km/s |
| Proper motion (μ) | RA: +90.848[2] mas/yr Dec.: −33.013[2] mas/yr |
| Parallax (π) | 12.9142±0.0177 mas[2] |
| Distance | 252.6 ± 0.3 ly (77.4 ± 0.1 pc) |
| Absolute magnitude (MV) | 3.80[1] |
| Details | |
| Mass | 1.275±0.018[5] M☉ |
| Radius | 1.5007±0.0076[5] R☉ |
| Luminosity | 2.76+0.19 −0.13[6] L☉ |
| Surface gravity (log g) | 4.184±0.024[6] cgs |
| Temperature | 6,046+76 −72[6] K |
| Metallicity | +0.208±0.058[6] dex |
| Rotation | ~12.8 d[7] |
| Rotational velocity (v sin i) | 2.8±0.5[8] km/s |
| Age | 3.37+0.20 −0.47[5] Gyr |
| Other designations | |
| Nushagak, AG+71 95, BD+71 171, HD 17156, HIP 13192, SAO 4737, PPM 5099, TOI-1573, TIC 302773669, TYC 4321-1320-1, GSC 04321-01320[9] | |
| Database references | |
| SIMBAD | data |
| Exoplanet Archive | data |
HD 17156, named Nushagak by the IAU,[10] is a yellow subgiant star approximately 253 light-years away in the constellation of Cassiopeia. The apparent magnitude is 8.16, which means it is not visible to the naked eye but can be seen with good binoculars.[9] It hosts one known exoplanet, HD 17156 b. A search for a binary companion star using adaptive optics at the MMT Observatory was negative.[11]
The designation HD 17156 comes from the Henry Draper Catalogue.
This was one of the systems selected to be named in the 2019 NameExoWorlds campaign during the 100th anniversary of the IAU, which assigned each country a star and planet to be named. This system was assigned to the United States. The star was given the name Nushagak, with the comment that "Nushagak is a regional river near Dillingham, Alaska, which is famous for its wild salmon that sustain local Indigenous communities."[10] The planet HD 17156 b was given the name Mulchatna, after a tributary of the Nushagak river.
The star is more massive and larger than the Sun, while its absolute magnitude of 3.70 and spectral type of G0 show that it is both hotter and more luminous. Based on asteroseismic density constraints and stellar isochrones, it was found that the age is 3.37 +0.20
−0.47 billion years making it about two thirds as old as the Sun. Spectral observations show that the star is metal-rich.[7][5]
An exoplanet, HD 17156 b (later named Mulchatna), was discovered with the radial velocity method in 2007,[7] and subsequently was observed to transit the star. At the time it was the transiting planet with the longest period.[12] It is a gas giant more massive than Jupiter with a close-in, eccentric orbit.[12] HD 17156 is the first star in Cassiopeia around which an orbiting planet was discovered.[citation needed]
Observations have ruled out the presence of any additional Jupiter-mass planets within 10 AU of the star.[6]
| Companion (in order from star) |
Mass | Semimajor axis (AU) |
Orbital period (days) |
Eccentricity | Inclination | Radius |
|---|---|---|---|---|---|---|
| b / Mulchatna | 3.26±0.11 MJ | 0.1632±0.0027 | 21.2164294(61) | 0.6772+0.0045 −0.0044 |
86.51+0.37 −0.34° |
1.094+0.031 −0.030 RJ |