<p><a href="http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD%2051684&amp;submit=SIMBAD%20search#lab_ident" rel="nofollow noreferrer">Simbad gives</a> a parallax of 4.0452 mas, which is equivalaent to 1/0.0040452 parsecs.</p>
<p>That is 247 parsecs or 805 light years  (but the error bars on that are quite high, 0.59 mas ie from 700 to  940 light years)</p>
<p>It is listed as in <a href="http://vizier.u-strasbg.fr/viz-bin/VizieR-S?HD%2051684" rel="nofollow noreferrer">spectral class F0</a>, which means up to about 1.5 times the mass of the sun.  It is also listed as a double star, so this refers to the major component.</p>

CC BY-SA 4.0
2021-03-20T12:56:10.577Z
Thank you very much
Elena Greg
CC BY-SA 4.0
2021-03-20T12:09:14.173Z
2021-03-20T12:09:14.173Z
James K
<p>HD 51684 is a magnetic Ap star. It has an entry in the recent catalogue of fundamental parameters for magnetic stars by <a href="https://ui.adsabs.harvard.edu/abs/2019AstBu..74...66G/abstract" rel="noreferrer">Glagolevskij (2019)</a>. This catalogue lists it as having <span class="math-container">$T_{\rm eff}=7800$</span> K, and a mass of <span class="math-container">$2.3 M_\odot$</span>.</p>
<p>These parameters are determined from the photometric properties of the star - i.e. they are not fundamental measurements of the temperature or mass.</p>
<p>The mass quoted by <a href="https://ui.adsabs.harvard.edu/abs/2019A%26A...623A..72K/abstract" rel="noreferrer">Kervella et al. (2019)</a>, in a study of binarity using Gaia data (HD 51684 is a known binary) is <span class="math-container">$2.195M_\odot$</span>. However this is spurious precision; this mass comes from matching the inferred luminosity and temperature to stellar evolutionary models, not from a measurement of the binary motion.</p>
<p>The distance has been most precisely and accurately determined by <a href="http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-ref=VIZ6055ed174eb0&amp;-out.add=.&amp;-source=I/350/gaiaedr3&amp;-c=104.12449018510%20-40.99022552020,eq=ICRS,rs=2&amp;-out.orig=o" rel="noreferrer">Gaia EDR3</a>
The parallax is <span class="math-container">$4.51 \pm 0.24$</span> arcsec. Roughly speaking, you can invert that to give a distance of <span class="math-container">$222 \pm 12$</span> pc.</p>

CC BY-SA 4.0
2021-03-20T12:56:21.990Z
Thank you very much
Elena Greg
CC BY-SA 4.0
2021-03-20T12:44:21.953Z
2021-03-20T12:44:21.953Z
ProfRob
<p>Where to find, if it is possible, values of the mass and the distance of HD 51684, please? Many thanks.</p>

CC BY-SA 4.0
2021-03-20T12:16:06.527Z
A very specific question.  Would you care to explain the significance of this star to you?
James K
CC BY-SA 4.0
2021-03-20T12:57:54.480Z
I was just looking for some parameters of several stars and this strikes me to be unclear. Many thanks for demonstrating other ways of searching.
Elena Greg
CC BY-SA 4.0
2021-03-21T23:21:42.863Z
Not every question has to be long or reveal "motive". This one is clear, concise and answerable as-is. The vote to close because it "should include more details and clarify the problem" **is unproductive, clutters the review queue and makes unnecessary work for others**
uhoh
<star>
HD 51684 - mass and distance
Elena Greg
# HD 51684 - mass and distance

(Asked by: username_0 on 2021-03-20)

Where to find, if it is possible, values of the mass and the distance of HD 51684, please? Many thanks.

**Tags:** star
> **Comments:**
> **username_1**: A very specific question.  Would you care to explain the significance of this star to you?  
> **username_0**: I was just looking for some parameters of several stars and this strikes me to be unclear. Many thanks for demonstrating other ways of searching.  
> **username_2**: Not every question has to be long or reveal "motive". This one is clear, concise and answerable as-is. The vote to close because it "should include more details and clarify the problem" **is unproductive, clutters the review queue and makes unnecessary work for others**  

---

## 2 answers

### Answer by username_3 on 2021-03-20. Score: 6 | Accepted answer

HD 51684 is a magnetic Ap star. It has an entry in the recent catalogue of fundamental parameters for magnetic stars by [Glagolevskij (2019)](https://ui.adsabs.harvard.edu/abs/2019AstBu..74...66G/abstract). This catalogue lists it as having $T\_{\rm eff}=7800$ K, and a mass of $2.3 M\_\odot$.

These parameters are determined from the photometric properties of the star - i.e. they are not fundamental measurements of the temperature or mass.

The mass quoted by [Kervella et al. (2019)](https://ui.adsabs.harvard.edu/abs/2019A%26A...623A..72K/abstract), in a study of binarity using Gaia data (HD 51684 is a known binary) is $2.195M\_\odot$. However this is spurious precision; this mass comes from matching the inferred luminosity and temperature to stellar evolutionary models, not from a measurement of the binary motion.

The distance has been most precisely and accurately determined by [Gaia EDR3](http://vizier.u-strasbg.fr/viz-bin/VizieR-5?-ref=VIZ6055ed174eb0&-out.add=.&-source=I/350/gaiaedr3&-c=104.12449018510%20-40.99022552020,eq=ICRS,rs=2&-out.orig=o)
The parallax is $4.51 \pm 0.24$ arcsec. Roughly speaking, you can invert that to give a distance of $222 \pm 12$ pc.

> **Comments:**
> **username_0**: Thank you very much  

---

### Answer by username_1 on 2021-03-20. Score: 3

[Simbad gives](http://simbad.u-strasbg.fr/simbad/sim-basic?Ident=HD%2051684&submit=SIMBAD%20search#lab_ident) a parallax of 4.0452 mas, which is equivalaent to 1/0.0040452 parsecs.

That is 247 parsecs or 805 light years (but the error bars on that are quite high, 0.59 mas ie from 700 to 940 light years)

It is listed as in [spectral class F0](http://vizier.u-strasbg.fr/viz-bin/VizieR-S?HD%2051684), which means up to about 1.5 times the mass of the sun. It is also listed as a double star, so this refers to the major component.

> **Comments:**
> **username_0**: Thank you very much  

---

